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Health Literacy: A Prescription to End Confusion (2004)

Chapter: 3 Extent and Associations of Limited Health Literacy

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Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

3
The Extent and Associations of Limited Health Literacy

This report has already noted that an individuals’ health literacy level is the product of a complex set of skills and interactions on the part of the individual, the health-care system, the education system, and the cultural and societal context. It has also been noted that most individuals will encounter health literacy barriers at some point. High educational attainment may not be sufficient to negotiate medical and technical language and meanings. The following chapters discuss in more detail some of the barriers and potential approaches to health literacy in the various contexts. Here, the focus is on the individual, and particularly, on the individual who has limited literacy skills. This chapter provides an overview of how limited health literacy may restrict an individual’s participation in health contexts and activities. Look at Figure 3-1 on the following page and put yourself in the shoes of a patient with limited literacy skills. How would you feel, what would you do, where would you go, to whom would you turn if this medication is prescribed for you by your doctor? How compliant could you be about taking your medications correctly?

Navigating modern life in America with very limited literacy can be like trying to find a hotel in another land, armed with a map of the city but unable to decipher the letters on the street signs. Everyone—not just those with limited literacy skills—is increasingly faced with difficult and confusing text at work, at home, in institutional settings such as schools, banks, social service organizations, and within health-care settings. People of all literacy levels might be able to manage texts that they frequently encounter

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

FIGURE 3-1 Mock-up prescription medication instructions in Bahasa Malaysia, the written language of Malaysia.

SOURCE: Shinagawa and Foong (2003). Reprinted with permission.

and use for everyday activities, but will often face problems with unfamiliar types of text. For example, a woman who has never lived near a public transportation system may find herself unable to interpret a bus schedule. Directions for operating a particle accelerator, filing income tax returns, or choosing between health insurance plans may be similarly indecipherable for most adults, regardless of literacy skills in other contexts.

As discussed in detail in Chapter 2, current measures of health literacy rely primarily on print in the health context and not on the broad array of skills needed for true health literacy. However, since skills with the written word are linked to skills with the spoken word, we can use information from these measures as a starting point to make reasonable assumptions about the average health literacy skill level of adults in the United States. The following section examines the extent of the problem of health literacy, estimated from existing measures of literacy based on the National Adult Literacy Survey (NALS) and from assessments of health literacy.

LITERACY IN AMERICA

About 90 million (47 percent) U.S. adults cannot accurately and consistently locate, match, and integrate information from newspapers, advertisements, or forms (Kirsch et al., 1993). These adults can perform a variety of

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

straightforward tasks using printed materials; however, they are unlikely to perform, with accuracy and consistency, more challenging tasks using long or dense texts. These findings have been compared to those in 22 industrialized nations that participated in the International Adult Literacy Surveys. The U.S. scores are very similar to those in Canada, higher than those in England or Ireland, but lower than those in the Scandinavian countries (Organization for Economic Co-operation and Development and Statistics Canada, 2000). U.S. and international education and workforce researchers note that the average skill levels are barely sufficient for full participation in the civic and economic sectors of current industrialized societies (Sum et al., 2002). About 90 million adults have skills that are inadequate for many needed tasks.

Of the 90 million adults with limited literacy skills, about 42 million demonstrated skills in NALS Level 1. Of these, a small percentage had such limited English literacy skills that they were unable to respond to much of the survey. Most people performing at Level 1 can perform simple and routine tasks using uncomplicated materials. They can, for example, locate a single piece of information in a short and simple piece of text. However, they have trouble with tasks requiring them to locate or match several pieces of information in moderately complicated texts. Adults performing at NALS Level 1 can solve simple math problems when the numbers and the operations are provided but find it difficult to solve the same problems when they must locate the numbers and the operations in a piece of text (Kirsch, 2001; Kirsch et al., 1993). A package of over-the-counter pediatric cold medicine can be used as an example. An adult performing at NALS Level 1 would likely be able to locate the words child, children, pediatric on a package of cold medicine for children. However, one would not expect an adult with NALS Level 1 skills to be able to read a chart in order to identify “how much … syrup is recommended for a child who is 10 years old and weighs 50 pounds?” What makes this task so much more complex and difficult is the fact that the structure of the chart is in columns starting with age, then typical weights associated with age, then dosage by type including drops, syrup, chewable 80 mg, and chewable 160 mg. The typical reader would look down the column to find the age of the child and then over the row to the column for syrup. In very small print outside the chart itself there is a conditional statement that tells the reader “if child is significantly under- or overweight, dosage may need to be adjusted accordingly….” This level task would fall at NALS level 4 or 5 (Rudd et al., 2003).

Of the 90 million adults with limited literacy skills, 50 million adults nationwide demonstrated skills at NALS Level 2. Those adults who scored at NALS Level 2 can locate information in moderately complicated text, make low-level inferences using print materials, and integrate easily identifiable pieces of information. They can solve simple math problems when

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

the numbers and operations are found in familiar and uncomplicated materials. However, adults at Level 2 find it difficult to perform these operations in difficult text and to perform operations that are complicated by distracting information and complex texts (Morse, 2002). In addition, they will find the demands of the chart to determine dosage for children’s cold medicine difficult and, according to studies assessing informed consent documents, will find the process of informed consent arduous and most likely not possible.

Most of the adults in NALS Levels 1 and 2 are “literate”; however, adults in Level 1 are at a severe disadvantage and adults in Level 2 are disadvantaged, in relation to the demands of twenty-first century life. These findings have serious implications for the health sectors. Rudd, Kirsch, and Yamamoto, in a reanalysis of the NALS with a focus on health-related tasks only, report similar findings (Rudd et al., 2003). The 1992 NALS survey provides the most recent nationally representative population survey data on literacy skills of adults in the United States. The committee believes that levels of American literacy have not improved over the past decade and that health systems have become more complex. The committee looks forward to the publication of the National Assessment of Adult Literacy1 (NAAL), conducted in 2003, which contains health-related literacy tasks. The committee believes that the NAAL will significantly expand our understanding of literacy and health literacy in America, and regrets that the data are not yet available. In addition, a representative sample of American adults is included in the new international Adult Literacy & Lifeskills Survey (ALL).2 Linked to the NAAL framework, the ALL also contains health-related literacy tasks. These two surveys have the potential to provide detailed information on the extent of limited health literacy in America.

Demographic Associations with Limited Literacy

The largest proportion of American adults with limited literacy are native-born Caucasian speakers of English. Over half of the people with NALS Level 1 skills are Caucasians, and about 57 million Caucasian Americans have limited literacy skills (NALS Levels 1 and 2) (Kirsch et al., 1993). However, many groups with higher rates of limited literacy than would be predicted from population estimates alone were identified by the NALS. Groups with lower average proficiency scores include those who are poor, members of ethnic and cultural minorities, those who live in the southern

1  

For more information, see the NAAL on the National Center for Education Statistics web site: http://nces.ed.gov/naal/.

2  

For more information, see ALL on the Educational Testing Service web site: http://www.ets.org/all.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

and western regions of the United States, those with less than a high school degree or GED, and those who are above the age of 65. It is important to keep in mind that the NALS was performed only in English, and that clear differentials for literacy proficiencies can be seen within each population group on the basis of nativity, education, and access to economic resources (Kirsch et al., 1993). Table 3-1 displays the percentage of persons overall and various demographic groups that have NALS Level 1 or 2 literacy skills, the lowest of five skill levels. Each of these groups is discussed briefly below in order to highlight those that could potentially benefit from interventions aimed at improving health literacy.3

Adults over the age of 65 have more limited literacy proficiency than younger, working adults, according to the NALS data. However, cross-tabulations indicate that scores for elders vary by education level and access to financial resources (Kirsch et al., 1993). Hispanics, African Americans, Pacific Islanders, and Native Americans are also (including Alaska Natives) over-represented in the numbers of adults with lower literacy proficiency scores, as indicated by the NALS data (Kirsch et al., 1993). These populations have increased in number since 1992, when the NALS was performed, and as a group represent a larger proportion of the U.S. population (U.S. Census Bureau, 2002). Hispanic and Asian populations in particular have increased at a greater rate than other U.S. populations. While more recent literacy data is not yet available, these population increases may represent an increase in the number of individuals, and the percentage of American adults, affected by limited health literacy.

Individuals without a high school diploma or GED have lower levels of literacy proficiency than do those with a high school diploma or education beyond high school. Nearly all adults who did not finish eighth grade scored at Level 1 or 2 on the NALS, and 77 percent of these individuals scored at Level 1. Similarly, among individuals who entered high school but did not graduate, 81 percent scored at NALS Levels 1 or 2, while only 55 percent of high school graduates scored at those levels (Kirsch et al., 1993). Since between 400,000 and 500,000 students drop out of high school each year in the United States (Young, 2002), high school dropouts constitute a large population likely living without adequate literacy skills.

Overall, more than 70 percent of immigrants tested on the NALS scored at Levels 1 or 2. The NALS was conducted in English only. Thus the finding that 25 percent of those scoring in the lowest levels of literacy proficiency were immigrants to the United States might be expected, since many of

3  

The information in this section is drawn in part from the background paper “Outside the Clinician-Patient Relationship: A Call to Action For Health Literacy,” commissioned by the committee from Barry D. Weiss, M.D. The committee appreciates his contributions. The full text of the paper can be found in Appendix B.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

TABLE 3-1 Percentage of Adult Population Groups with Literacy Skills at NALS Levels 1, 2, or 3–4

 

Percent Respondents at Skill Level

Group

Level 1

Level 2

Levels 3–4

All NALS Respondents

22

28

50

Age

16–54 years

15

28

57

55–64 years

28

33

39

65 years and older

49

32

19

Highest Education Level Completed

0–8 years

77

19

4

9–12 years (no high school graduation)

44

37

19

High school diploma/GED (no college study)

18

37

45

Racial/Ethnic Group

White

15

26

59

American Indian/Alaska Native

26

38

36

Asian/Pacific Islander

35

25

40

Black

41

36

23

Hispanic (all groups)

52

26

22

Immigrants to US (various countries of origin)

0–8 years of education prior to arrival in US

60

31

9

9+ years of education prior to arrival in US

44

27

29

Disability

Any mental or emotional condition

48

26

27

Learning disability

59

22

19

Hearing difficulty

35

34

32

Speech disability

54

27

19

Visual difficulty

55

26

19

 

SOURCE: Unadjusted averages of prose and document literacy scores on the NALS as reported on Tables 1.1A, 1.1B, 1.2A, 1.2B, 1.8, and Figure 1.10 in Kirsch et al. (1993) and on Table B3.13 in the U.S. Department of Education’s report English Literacy and Language Minorities in the United States (2001).

those immigrants might have just begun to learn English. In addition, 91 percent of those who did not complete a high school education in their country of origin scored at the lowest levels of proficiency (see Table 3-1). A high proportion of people entering the United States from non-English-speaking nations come from non-industrialized areas of the world in which there are limited educational opportunities. For example, more than half of adults who emigrate to the United States from Spanish-speaking countries

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

had not finished high school in their country of origin (Greenberg et al., 2001).

Individuals who described themselves as having a physical or mental condition which prevented them from participating fully in normal activities tended to score at the lowest levels of proficiency. More than half the individuals with vision, speech, or learning disabilities performed at NALS Level 1, as did 48 percent of individuals reporting a mental or emotional condition. In contrast, 35 percent of individuals reporting a hearing difficulty performed at NALS Level 1.

Approximately 7 of 10 prisoners surveyed by the NALS demonstrated limited literacy proficiency. Individuals who did not finish school are over-represented among prison inmates, so in many cases, prisoners represent the same individuals as those with limited education. NALS investigators studied nearly 1,150 inmates in 80 federal and state prisons that had been randomly selected to represent penal institutions across the country (Haigler, 1994).

Several other groups, not specifically studied in the NALS, are also known to have limited literacy skills. These groups include the persons who are poor and/or homeless, and military recruits. As discussed in Chapter 2, social factors affect literacy. Poverty is intertwined with many sociodemographic variables (Balsa and McGuire, 2001), which, in turn, are associated with limited literacy. Although the causal relationships are not known, individuals with limited incomes/access to resources are also more likely than those with higher incomes/access to resources to have lower literacy proficiency (Kirsch et al., 1993). Homeless individuals, who may also be affected by limited literacy and poverty, are the audience recipients of a variety of state programs developed to enhance literacy skills (Profiles of State Programs, 1990). Weiss and colleagues used Medicaid enrollment as a proxy for low income and administered the Instrument for the Diagnosis of Reading/Instrumento Para Diagnosticar Lectura (IDL) as a measure of literacy. They found that the majority of low-income individuals involved in their study had limited reading skills, with the average score at the fifth-grade level (Weiss et al., 1994). In addition, reading and mathematics skills of potential military recruits are assessed, and enlistment in the military requires passing these tests. As many recruits cannot adequately perform the high school level reading tasks they face in the military, all branches of the military operate educational programs to increase the literacy skills of their members (Hegerfeld, 1999).

THE EPIDEMIOLOGY OF LIMITED HEALTH LITERACY

Ninety million people—approximately one-half of our adult population—lack the basic literacy skills required for full participation in Ameri-

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

can society (Comings et al., 2001; Sum et al., 2002). Basic literacy skills that can be applied in the context of health are required for health literacy. As discussed in Chapter 2, there are no assessment tools that fully measure health literacy, and consequently, no population-based study to date has directly examined the relationship of literacy to health literacy or of health literacy, as fully defined, to health. However, correlations between measures of literacy and measures of reading in the health context such as the Rapid Estimate of Adult Literacy in Medicine (REALM) and the Short Test of Functional Health Literacy in Adults (S-TOFHLA) suggest a strong association (Davis et al., 1993; Parker et al., 1995).

Routine health and health-care tasks are often complicated and may require more literacy skills than those needed to meet the demands of everyday life. To date, no researcher has fully delineated tasks needed for the full range of health-related activities nor has anyone fully calibrated the levels of complexity of the various types of materials used in health contexts. However, a review of health literature indicates that research findings over three decades place a wide variety of assessed materials (based primarily on reading level analyses) at levels that exceed the reading skills of most high school graduates (Rudd et al., 2000a). The substantial volume of literature focused on assessments of health-related materials.

Health literacy may also be more reliant on domains of literacy such as oral (speaking) ability and aural (listening) comprehension that are not measured by NALS, or the tools currently used to measure health literacy (discussed in Chapter 2 of this report). Recognizing that basic literacy skills are required for health literacy, it is reasonable to conclude that individuals with limited literacy—the 90 million individuals that scored in Levels 1 and 2 of NALS—probably also have limited health literacy. These individuals likely lack the necessary literacy skills in English needed to effectively obtain and understand much of the health-related information they will interact with at home, at work, or in their communities. Furthermore, limited health literacy probably affects more than just those with limited literacy. Individuals with adequate literacy may be affected by the complex literacy demands of the health-care context, and some individuals may continue to be affected despite attempts to reduce these demands. These findings, combined with the average NALS scores of U.S. adults, offer a strong argument that 90 million U.S. adults are severely disadvantaged as they attempt to function in health-care contexts. The committee considers health literacy to be a reciprocal function of the health context and the individual. Therefore, any person, no matter what literacy skills he or she possesses, may well have limited health literacy once he or she enters complex health-care contexts.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

I am a nurse with advanced degrees. I read on a college level. Yet, I am a total health illiterate. How can this be? Well, I’ve been diagnosed with an unusual type of autoimmune disease that has extended into several other diseases, one of which—lymphoma—might be fatal. Yet despite my healthcare background, my ability to understand the written word at a high grade level, and the many resources at my immediate disposal, I still don’t understand everything I need to know about my condition. I am writing this to share with you that it is difficult to piece together all the various components of the healthcare system even when you have a knowledgeable support system and excellent reading ability. I am sharing my personal health situation with you because even with all the supposed advantages I have as mentioned above, I still don’t understand my condition and prognosis (Mayer, 2003).

Finding 3-1 About 90 million adults, an estimate based on the 1992 NALS, have literacy skills that test below high school level (NALS Levels 1 and 2). Of these, about 40–44 million (NALS Level 1) have difficulty finding information in unfamiliar or complex texts such as newspaper articles, editorials, medicine labels, forms, or charts. Because the medical and public health literature indicates that health materials are complex and often far above high school level, the committee notes that approximately 90 million adults may lack the needed literacy skills to effectively use the U.S. health system. The majority of these adults are native-born English speakers. Literacy levels are lower among the elderly, those who have lower educational levels, those who are poor, minority populations, and groups with limited English proficiency such as recent immigrants.

Studies of Limited Health Literacy

In this section, we examine the extent of limited health literacy by examining peer-reviewed studies that provide evidence about the epidemiology, or relative rates, of health literacy skills using currently available measures in different demographic groups. The conclusions that can be drawn about health literacy from this research are limited because in most cases, the studies below identify individuals and groups in which only the print component of health literacy skills is measured (see Chapter 2).

Studies described in this and the following section represent a sample of the English-language peer-reviewed studies that measure literacy or use the REALM or TOFHLA among patients or consumers in a health context. We note that these measures are, for the most part, assessments of print literacy in the health context. While these measures all tap into some aspect of health literacy, the studies do not necessarily use the same standard for

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

identifying people with limited skills. It is even the case that any two tests both claiming to use grade-level scores would not identify the same students as being below a selected standard because their norming samples most likely were not the same. Thus the percentages falling below a particular standard are not directly comparable, but do clearly point to where problems exist.

Studies were identified by searching the Medline (1966–2003), PsycInfo (1974–2003), ERIC4 (1963–2003), Sociological Abstracts (1963–2003), and CINAHL5 (1982–2003) databases through the OVID web gateway for the indicated years with the following terms as keyword searches: “health literacy,” “literacy and health,” and “reading and health.” To be included, the study had to define the health or health-care population cohort, the literacy measurement tool, and the result of the literacy screening assessment. Additional studies for inclusion were identified through testimony to the committee by experts in the field (see Appendix A), and the available bibliographies (Greenberg, 2001; Rudd et al., 2000b; Zobel et al., 2003).

Table 3-2 summarizes identified studies containing information on the rates of health literacy skills as currently measured among various study populations. Results are given as percentages of the study participants with (1) marginal and inadequate health literacy as measured by the TOFHLA (Parker et al., 1995) or its shorter version (S-TOFHLA; Baker et al., 1999); or (2) inadequate health literacy as indicated by a score below grade 9 on the REALM (Davis et al., 1993); or (3) what the authors reported if a standard measure was not used or if a standard measure was modified. Table 3-2 also identifies the reported demographic characteristics of the study participants that were reported to be associated with limited health literacy.

Studies noted in Table 3-2 document the prevalence of limited health-literacy skills as measured by the REALM or TOFHLA among patients in general medical and pediatric clinics; specialty care clinics including those for asthma, HIV, family planning, obstetrics, and oncology; and community-based sites including retirement homes and social service agencies. The studies show that limited health literacy skills, as measured by current assessment tools, are common, with significant variations in prevalence depending on the population sampled (Williams et al., 1998b). In many cases, however, education was not controlled for, and in some cases differences based on health literacy assessments were no longer significant when education was controlled for.

Two large multisite studies of convenience samples that provide esti-

4  

Educational Resources Information Center.

5  

Cumulative Index to Nursing and Allied Health Literature.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

mates of the prevalence of limited health literacy among users of urban public hospitals showed variation in prevalence in different geographic locations. In one study, Williams and colleagues (1995) administered the TOFHLA in either English or Spanish to patients presenting for acute care at public hospitals in Atlanta and Los Angeles. The study participants included 1,892 English speakers from Atlanta or Los Angeles, and 767 Spanish-speaking individuals from Los Angeles only. Almost half (47.4 percent) of the participants in Atlanta had inadequate (34.7 percent) or marginal (12.7 percent) health literacy scores on the TOFHLA, while in Los Angeles the rates of limited and marginal health literacy scores were 12.5 percent and 9.5 percent for English speakers and 41.9 percent and 19.8 percent for Spanish speakers. Spanish-speaking participants (tested in Spanish) had higher rates of limited health literacy scores than did English-speaking participants, but these differences were not significant after controlling for years of education.

A more recent multisite study used the S-TOFHLA to assess new enrollees in a Medicare managed care organization in four different geographic areas: Cleveland, Houston, Tampa, and an area of southern Florida including Fort Lauderdale and Miami (Gazmararian et al., 1999b). Participants were 304 Spanish-speaking and 2,956 English-speaking enrollees. The prevalence of inadequate and marginal health literacy scores on the S-TOFHLA among English speakers was 23.5 percent and 10.4 percent, respectively, while among Spanish speakers prevalence rates were 34.2 percent and 19.7 percent. Results varied by city, with the participants in Cleveland showing the highest rate of inadequate health literacy scores among English speakers at 34.1 percent, and those in Tampa showing the lowest rate at 16.6 percent. The geographic variation between Spanish-speaking populations was even more striking; 60 percent of those in Tampa had inadequate health literacy scores compared with 21.2 percent of those in Houston. The authors of this study indicated that the geographic variation between study sites might reflect differences in the interrelated characteristics of race, language, and socioeconomic status. However, when these variables were controlled for, participants in Cleveland continued to show the highest rates of limited health literacy scores among English speakers. Factors mediating geographic differences in skills remain unknown and warrant further investigation. Increased awareness of these variations could lead to regionally tailored health literacy interventions.

Studies shown in Table 3-2 suggest that the segments of the U.S. population that could be considered at greatest risk for limited health literacy are those that were reported to have higher rates of limited literacy in the NALS study and other sources. As with limited literacy reported in the NALS (Kirsch et al., 1993), limited health literacy as currently measured is more prevalent among the elderly (Beers et al., 2003; Benson and Forman, 2002;

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

TABLE 3-2 The Epidemiology of Health Literacy Skills Among Various Populations

Citation

Population

Participation Rate

Study Design

Setting

Arnold et al., 2001

N = 600

Pregnant women

296 African American

303 Caucasian

Mean age: 23 years

96%

Convenience sample

Obstetric clinics, Louisiana

Beers et al., 2003.

Published Abstract

N = 1805

58% African American

66% male

(Health Literacy and Patient Satisfaction Study)

Primary care clinics, VA medical center and university hospital

Bennett et al., 1998

N = 212

African American, 103

Mean age: 70.8 years

96%

Convenience sample

Prostate clinics in Shreveport, LA, and Chicago, IL

Benson and Forman, 2002

N = 93

71 women

Mean age: 83 years

52%

Convenience sample

Affluent retirement community in Albuquerque, NM

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Measure

Reported Demographic Associations with Low Health Literacy

Prevalence of Literacy Levels

REALM

African American race

African American women

3rd and below: 9%

4th–6th: 19%

7th–8th: 41%

9th and above: 31%

Caucasian women

3rd and below: 4%

4th–6th: 5%

7th–8th: 26%

9th and above: 66%

REALM

African American race

Older age

Lower education level

Association with age was no longer significant when stratified by education level

Association with race remained significant when stratified by education level

REALM

3rd and below: 2%

4th–6th: 8%

7th–8th: 31%

9th and above: 59%

REALM

African American race

Geographic location (Louisiana site)

African American men

6th and below: 52.3%

Caucasian men:

6th and below: 8.7%

Chicago, IL:

6th and below: 12.3%

Shreveport, LA:

6th and below: 38.1%

TOFHLA

Older age

Fewer years of education

74% or less on TOFHLA: 30%

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Davis et al., 1994

N = 396

Parents or other caretakers accompanying pediatric outpatients

Mean age: 30 years

96%

Pediatric clinic in a public hospital, Louisiana

Fortenberry et al., 2001

N = 1035

Mean age: 26.36

78%

Clinics, community-based organizations, and by street intercept in 4 sites (CO, IN, NY, and AL)

Gazmararian et al., 1999b

N = 3260

New Medicare enrollees

2,956 English speakers, 304 Spanish speakers

Age distribution:

65–69 years: 37%

70–74 years: 27.3%

75–79 years: 19.3%

80–84 years: 11%

≥ 85 years: 5.4%

39%

3,260 participated out of 8,409 identified for study

Cohort

Prudential Medicare Managed Care Study 4 sites: Cleveland, OH, Houston, TX, south Florida, and Tampa, Florida

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Measure

Reported Demographic Associations with Low Health Literacy

Prevalence of Literacy Levels

 

REALM and WRAT-R

REALM

3rd and below: 11%

4th–6th: 16%

7th–8th: 37%

9th and above: 35%

WRAT

Less than 4th: 31%

Less than 7th: 55%

Less than 9th: 73%

REALM

8th and below: 35%

9th and above: 65%

S-TOFHLA

African American race

Total

Older age

English

Spanish

Fewer years of school completed

History of blue collar occupations

Inadequate: 23.5%

Marginal: 10.4%

Adequate: 66.1%

Inadequate: 34.2%

Marginal: 19.7%

Adequate: 46.1%

Older age was strongly associated with lower health literacy, and this association remained after adjusting for years of school completed and cognitive impairment

Cleveland, OH

English

Inadequate: 34.1%

Marginal: 9.9%

Adequate: 56.0%

Houston, TX

English

Spanish

Inadequate: 28.0%

Marginal: 9.4%

Adequate: 62.6%

Inadequate: 21.2%

Marginal: 19.2%

Adequate: 59.6%

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Gazmararian et al., 1999a

N = 406

Women enrolled in a Medicaid managed care plan

Age distribution:

19–24 years: 144

25–29 years: 86

≥ 30 years: 175

19%

406 participated out of 2,197 identified for study

Cohort

Medicaid managed care plan in Memphis, Tennessee

Kalichman et al., 2000

N = 228

HIV clinics, AIDS adults

Mean age: 39.7 years

Convenience sample

HIV-infected service organizations, social service agencies

Kalichman et al., 1999

N = 182

HIV-infected adults

Mean age: 39.1 years

Convenience sample

HIV clinics, AIDS service organizations, social service agencies

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Measure

Reported Demographic Associations with Low Health Literacy

Prevalence of Literacy Levels

 

 

South Florida

English

Inadequate: 17.3%

Marginal: 11.6%

Adequate: 71.1%

Spanish

Inadequate: 34.3%

Marginal: 20.3%

Adequate: 45.4%

 

 

Tampa, FL

English

Inadequate: 16.6%

Marginal: 10.2%

Adequate: 73.2%

Spanish

Inadequate: 60.0%

Marginal: 16.0%

Adequate: 24.0%

TOFHLA (abbreviated version)

Lower education level

Health literacy levels were not significantly associated with age, race, marital status, employment status, and poverty status

9.6% scored less than 80% on the TOFHLA

TOFHLA

Fewer years of education

Ethnic/minority status

Health literacy level was not related to age, income level, gender, or sexual orientation

TOFHLA Scores:

0%–20%: 2%

21%–40%: 2%

41%–60%: 3%

61%–80%: 11%

81%–90%: 23%

91%–100%: 59%

 

TOFHLA

 

41% scored below 85% on the TOFHLA

 

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Kaufman et al., 2001

N = 61

First-time mothers aged 18 years or older who had an infant between 2 and 12 months

Convenience sample

Public health clinic, NM Albuquerque,

Li et al., 2000

N = 55 (REALM scores available on 39)

Women with early-stage breast cancer

71%

39 patients participated in REALM testing out of 55 identified by retrospective chart review

Convenience sample

Clinic in the rural south

Lindau et al., 2002

N = 529

English-speaking patients older than 18 years

Median age: 27

91%

Prospective Cohort

Ambulatory Obstetrics and Gynecology clinic and a women’s HIV clinic

Montalto and Spiegler, 2001

N = 70

Female: Mean age: 45

Male: Mean age: 55

38.%

 

Rural community health center

Schillinger et al., 2002

N = 408

English- and Spanish-speaking type-2 diabetes patients older than 30 years

(San Francisco General Diabetic Patients with Low Health Literacy Study)

91%

Cross-sectional

Two primary care clinics, public hospital, San Francisco, CA

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Measure

Reported Demographic Associations with Low Health Literacy

Prevalence of Literacy Levels

REALM

3rd and below: 0%

4th–6th: 0%

7th–8th: 36%

9th and above: 64%

 

REALM

3rd and below: 0%

4th–6th: 12.8%

7th–8th: 12.8%

9th and above: 74.4%

 

REALM

Non-white participant

Those with no or public health insurance

6th and below: nearly 10%

7th–8th: 33%

9th and above: 61%

 

TOFHLA

 

Inadequate: 2.86%

Marginal: 11.43%

Adequate: 85.71%

 

S-TOFHLA

Older age

Female gender

Non-white

Spanish-speakers

Lower education level

Medicare coverage

Longer time with diabetes

English

Inadequate: 27.7%

Marginal: 12.7%

Adequate: 59.6%

Spanish

Inadequate: 56.8%

Marginal: 14.2%

Adequate: 29.9%

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Shea et al., 2003.

Published abstract

N = 2494

(Health literacy based practices satisfaction study)

Cohort

Urban community-and patient

Weiss et al., 1994

N = 402

Medicaid enrollees, 21.6% Male, 78.4% Female 45.8% Hispanic 42.8% Caucasian 5.5% African American

Mean age: 49.0

75%

Cohort

University Family Care, a health care organization in Tucson, AZ

Williams et al., 1998a

N = 483

273 from emergency department (ED)

210 from asthma clinic (AC)

ED Mean age: 37

AC Mean age: 47

ED = 79%

AC = 90%

Cohort

ED and AC at urban public hospital, Atlanta, GA

Williams et al., 1998b

N = 516

Patients with hypertension (n = 402) and patients with diabetes (n = 114)

 

94% (LA)

86% (Atlanta)

Cohort

General medical clinics of two urban public hospitals (Atlanta and Los Angeles)

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Measure

Reported Demographic Associations with Low Health Literacy

Prevalence of Literacy Levels

S-TOFHLA

Inadequate: 25%

Marginal: 11%

Adequate: 65%

 

Instrument for the Diagnosis of Reading/ Instrumento Diagnosticar Para Lecturas (IDL)

Spanish-speaking

0:8.7%

1st: 4.7%

2nd: 5.1%

3rd: 5.6%

4th: 4.2%

5th: 5.2%

6th: 13.7%

7th: 14.2%

8th and above: 38.6%

 

REALM

Older age

3rd and below: 13%

4th–6th: 27%

7th–8th: 33%

9th and above: 27%

 

TOFHLA

Older age

Spanish-speaking

Diabetes patients*

Inadequate: 44%

Marginal: 11%

Adequate: 45%

Hypertension patients*

Inadequate: 49%

Marginal: 12%

Adequate: 39%

 

 

*results include both Spanish- and English-speaking individuals

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Williams et al., 1995

N = 2,659

Patients presenting for acute care, 1892 English speakers, 767 Spanish speakers

(Literacy in Health Care study)

77.% Atlanta,

84% Los Angeles

Cohort

Two urban public hospitals in Atlanta and Los Angeles

REALM: 4 levels: (1st–3rd, 4th–6th, 7th–8th, 9th and above).

TOFHLA: Inadequate health literacy (score 0–59), marginal health literacy (score 60–74), adequate health literacy (score 75–100).

Gazmararian et al., 1999b; Schillinger et al., 2002; Williams et al., 1995, 1998a, b). Limited literacy and health literacy as measured by these studies in older adults is an important problem. Older individuals generate high health-care costs (Berk and Monheit, 2001). High health-care costs, in turn, are associated with limited literacy (see below for a detailed discussion). While older individuals have some of the highest rates of limited health literacy scores and limited functional literacy scores, they also have some of the most demanding health-care needs. Limited health literacy in older adults may contribute to a situation in which those most in need of health care may be those least able to access and benefit from the care.

Studies with current health literacy measures have reported that demographic associations with limited health literacy include racial or ethnic minority status (Arnold et al., 2001; Beers et al., 2003; Bennett et al., 1998; Gazmararian et al., 1999b; Kalichman et al., 2000; Lindau et al., 2002; Schillinger et al., 2002), fewer years of schooling or lower education level (Beers et al., 2003; Benson and Forman, 2002; Gazmararian et al., 1999a, b; Kalichman et al., 2000; Schillinger et al., 2002), and being a Spanish-speaker (tested in Spanish; Weiss et al., 1994). Notably, these demographic groups identified by several assessments conducted in different settings are the same demographic groups identified by the NALS, discussed earlier. However, none of these studies have involved a sufficiently large random sample of adults that would allow us to extrapolate these findings to other populations.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Measure

Reported Demographic Associations with Low Health Literacy

Prevalence of Literacy Levels

TOFHLA

Age 60 years or above

Spanish-speaking

Los Angeles

English

Inadequate: 12.5%

Marginal: 9.5%

Adequate: 78%

Spanish

Inadequate: 41.9%

Marginal: 19.8%

Adequate: 38.3%

 

 

Atlanta

Inadequate: 34.7%

Marginal: 12.7%

Adequate: 52.6%

 

S-TOFHLA: Inadequate health literacy (score 0–53), marginal health literacy (score 54–66), adequate health literacy (67–100).

IDL: Grade level scores from 0 to 8, 0 indicating failure at grade level 1, 8 indicating reading comprehension at or above the 8th grade level.

THE ASSOCIATIONS OF LIMITED HEALTH LITERACY

Research study findings linking the presence of limited health literacy as currently measured to poor health are accumulating, although the causal relationship between health literacy and health is unknown. This research can be thought of as addressing two types of costs associated with limited health literacy: economic costs to society and the health-care system, and costs in terms of the human burden of disease. This section will review both peer-reviewed and new evidence of the association of limited health literacy as measured by the REALM or TOFHLA with health outcomes, health-related knowledge and behaviors, and economic costs. The personal costs of limited health literacy also bear consideration. Many adults overestimate their knowledge and understanding of health information, including instructions for their own care (Davis et al., 1996; Doak et al., 1996). Others may be all too aware of their difficulty understanding health information. Limited health literacy may also take a psychological toll; one study found that those with limited health literacy as measured by the S-TOFHLA reported a sense of shame about their skill level (Parikh et al., 1996).

Finding 3-2 On the basis of limited studies, public testimony, and committee members’ experience the committee concludes that the shame and stigma associated with limited literacy skills are major barriers to improving health literacy.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Associations with Health Knowledge, Behavior, and Outcomes

Individuals with inadequate health literacy as currently measured report less knowledge about their medical conditions and treatment, worse health status, less understanding and use of preventive services, and a higher rate of hospitalization than those with marginal or adequate health literacy (for review, see Parker et al., 2003). Table 3-3 displays a sampling of studies that provide evidence of health-related associations with health literacy as measured by currently available assessments of print literacy in the health context. These studies were identified using the same methodology as described in the previous section.

A number of researchers examined relationships between patients’ scores on the REALM or TOFHLA, knowledge of illnesses, and chronic condition management. Studies included in Table 3-3 demonstrate that hypertension, diabetes, asthma, and HIV/AIDS patients with lower scores have less knowledge of their chronic illness and its management than those with higher scores (Kalichman et al., 2000; Schillinger et al., 2002; Williams et al., 1998a, b). Examination of health literacy scores and health-care management found that patients with limited health literacy as determined by current measures have a decreased ability to share in decision making about prostate cancer treatment (Kim et al., 2001), lower adherence to anticoagulation therapy (Lasater, 2003; Win and Schillinger, 2003), and worse glycemic control (Arnold et al., 2001; Kalichman and Rompa, 2000; Schillinger et al., 2002; Williams et al., 1998a, b).

As noted in Table 3-3, several studies have demonstrated a relationship between hospitalization rates and limited health literacy as measured by the TOFHLA or REALM (e.g., Baker et al., 1997, 2002a). For example, Gordon and colleagues (2002) demonstrated that although rheumatoid arthritis patients of differing literacy levels had similar levels of rheumatoid arthritis-related dysfunction, those scoring lower on the REALM had significantly more hospital visits in the previous 12 months than age- and sex-matched controls with higher scores. Arozullah and colleagues (2002) investigated the relationships between health literacy level, the preventability of hospital admissions, and the causes of preventable hospital admissions. Patients scoring at or below the third-grade level on the REALM had an increased risk (odds ratio (OR) = 8.5) of preventable admission as compared to those scoring at the ninth-grade level and above, while patients with fourth- to eighth-grade literacy had an OR for preventability of 2.5. Furthermore, preventable admissions among patients with literacy levels at or below sixth grade were more likely than preventable admissions among those with above sixth-grade literacy to be related to system-level factors such as the availability of outpatient diagnostic care.

Health literacy level has also been linked to self-reported health status. Baker and colleagues found that among both individuals at a public hospi-

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

tal (1997) and in a Medicare managed care health plan (2002a), those with inadequate health literacy as determined by the TOFHLA were significantly more likely than patients with adequate health literacy scores to report their health as poor.

Health literacy levels may influence health status by affecting care-seeking behavior. A study by Bennett and colleagues (1998) indicated that individuals with lower health literacy scores on the REALM may enter the health-care system when they are sicker than those with higher health literacy scores; among men with prostate cancer, those scoring lower on the REALM were more likely to be initially diagnosed at a more advanced stage of disease than those with higher health literacy. However, this difference was not statistically significant after adjustments for race, age, and location or care. Several studies have showed that individuals with lower health literacy scores are less likely than those with higher health literacy scores to make use of preventive health-care services. Scott and colleagues (2002) found that, among Medicare managed care enrollees, those with inadequate health literacy, as measured by the S-TOFHLA, used preventive health services (including influenza and pneumococcal vaccinations, mammogram, and Pap smear) less than enrollees with higher health literacy. Similarly, Fortenberry and colleagues (2001) administered the REALM test to 1,035 people in four sites across the country, and found that higher REALM scores were independently associated with gonorrhea testing in the previous year. In contrast, Moon and colleagues (1998) found no relationship between parental literacy levels, as measured by the REALM, and use of preventive health services for pediatric patients.

Finding 3-3 Adults with limited health literacy, as measured by reading and numeracy skills, have less knowledge of disease management and of health-promoting behaviors, report poorer health status, and are less likely to use preventive services.

While research in developing countries rarely examines health literacy, a number of studies have examined the association between literacy or reading levels and health outcomes. A Bolivian study found that children of individuals participating in health, literacy, or small business financing programs offered through an international non-governmental organization were at less risk of becoming malnourished than children from comparison communities (Gonzales et al., 1999). A World Bank study of the association between maternal educational attainment and child health in Morocco found that the mother’s health knowledge was associated with improved child health and nutrition (Glewwe, 1999). In contrast, a 10-year study of factors influencing infant and child health in Pakistan showed notable improvements in indicators of health, including a 69 percent increase in vacci-

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

TABLE 3-3 Health-Related Associations of Health Literacy Skills

Citation

Population

Participation Rate

Study Design

Setting

Arnold et al., 2001

N = 600

Pregnant women

296 African American

303 Caucasian

Mean age: 23

96%

Convenience sample

Obstetric clinics, Louisiana

Baker et al., 2002b

N = 2,787

Medicare enrollees

354 African American

2,343 Caucasian

Mean age: 73

37%

2,787 of 7,471 selected enrollees

Cohort

Prudential Medicare managed care (4 sites)

Baker et al., 2002a

N = 3,260

Medicare enrollees

2,956 English speakers

304 Spanish speakers

44%

3,260 of 7,471 selected enrollees

Prospective cohort

Prudential Medicare managed care (4 sites)

Baker et al., 1998

N = 979 (Literacy in Health Care Study)

Prospective cohort

Large public hospital emergency department; Atlanta

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection

Method Health-Related Outcome Associations

REALM

Structured interview

Urine cotinine levels

Self-report of smoking practices

Participants scoring lower on the REALM had less knowledge about the effects of smoking and less concern about the health effects of smoking on their baby than those with higher scores.

REALM scores were not related to smoking practices even when race, age, and living with a smoker were controlled.

S-TOFHLA

Mini-Mental State Examination (MMSE)

Self-report

Health literacy was linearly related to the total MMSE score across the entire range of S-TOFHLA scores.

S-TOFHLA

Structured interview

MMSE

Geriatric Depression Scale

Short Form-12 Health Survey (SF-12), a measure of self-rated physical and mental health

Managed care organization claims

Participants with inadequate and marginal health literacy reported worse health status. They were also significantly more likely to have been hospitalized than those with adequate health literacy. This relationship remained after adjusting for demographics, income, schooling, cognitive function, and social support.

Spanish-speaking individuals at all literacy levels had a lower risk of admission than English speakers.

TOFHLA

Structured interview

Grady Memorial Hospital information system

Patients with inadequate literacy were significantly more likely to be hospitalized one or more times than those with marginal or adequate literacy. This association remained after adjusting for age, gender, race, self-reported health, socioeconomic status, and health insurance.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Baker et al., 1997

N = 2,659

979 Atlanta

Los Angeles

913 English speakers

767 Spanish speakers (Literacy in Health Care Study)

81%

Prospective cohort

Two large public hospitals: Atlanta and Los Angeles

Bennett et al., 1998

N = 212

Low-income men

109 African American

103 Caucasian

Mean age: 70.8

96%

Convenience sample

Prostate clinics in Shreveport, LA and Chicago, IL

Fortenberry et al., 2001

N = 1,035

Mean age: 26

78%

Convenience sample

Clinics, community-based organizations, and by street intercept (4 states: CO, IN, NY, and AL)

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection Method

Health-Related Outcome Associations

TOFHLA

Interview

Participants with inadequate health literacy were significantly more likely than participants with adequate health literacy to report poor health. This association remained after controlling for age, gender, race, and socioeconomic indicators.

No relationship existed between literacy level and ambulatory care use after adjusting for age, health status, and economic indicators. At one of the study sites (Atlanta, GA), patients with inadequate literacy were more likely to have been hospitalized in the year preceding the study, and this relationship remained after controlling for age, gender, race, socioeconomic indicators, and self-reported health.

REALM

Medical record review

Pathology reports

Participants with literacy levels below the sixth grade were significantly more likely to present with Stage D cancer than those with higher literacy levels.

REALM

Structured interview

After adjustment for missing REALM data, a REALM score of ninth grade or higher was independently associated with gonorrhea testing in the previous year. (Other independent predictors of testing were past suspicion of gonorrhea, self-inspection for gonorrhea, self-efficacy for care seeking, and younger age).

Participants scoring lower on the REALM rated themselves more likely to acquire gonorrhea in the next 12 months than those with higher REALM scores.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Gazmararian et al., 1999a

N = 406

Women enrolled in health plan

Age distribution:

19–24:144

25–29:86

≥ 30:175

19%

2,197 identified for study: 1,061 not located.

Cohort

Medicaid managed care, Memphis, Tennessee

Gazmararian et al., 2000

N = 3,260

New Medicare enrollees

2,956 English speakers

304 Spanish speakers

76% Caucasian

44%

Cohort

Prudential Medicare managed care (4 sites)

Gordon et al., 2002

N = 123

Patients with rheumatoid arthritis Median age: 56 years

Range:

19–77 years

96.8%

Cross-sectional

Arthritis clinic

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection Method

Health-Related Outcome Associations

S-TOFHLA

Interview

Higher rates of low health literacy were observed among participants who had ever used an intrauterine device, douching, rhythm, or levonorgestrel implants as methods of birth control than women who had used other methods of birth control.

Compared with women with good reading skills, women with low reading skills were 2.2 times (95% confidence interval [CI] 1.1, 4.4) more likely to want to know more about birth control methods and 4.4 times (95% CI 2.2, 9.0) more likely to have incorrect knowledge about when they were most likely to get pregnant. These relationships were significant after controlling for age, race, and marital status.

There was no relationship between health literacy levels and either pregnancy intendedness or current use of contraception.

S-TOFHLA

Geriatric Depression Scale

Interview

Participants with inadequate health literacy skills were significantly more likely to report depressive symptoms than those with adequate health literacy skills. However, this association was no longer significant after controlling for health status.

REALM

Interview

Case record review

Health Assessment Questionnaire

Hospital Anxiety and Depression Scale

Carstairs Index of social deprivation

REALM scores not related to disease duration, numbers of joint replacements, or number of previous disease-modifying antirheumatic drugs.

“Illiterate” patients had three times as many hospital visits as controls in the previous 12 months.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Guerra and Shea, 2003.

Published Abstract

N = 1,301

Patients over 18 years of age insured by Medicaid or Medicare

Mean age: 42.2

(Health Literacy and Patient Satisfaction Study)

49%

Convenience sample

Four community-and one university-based primary care practice

Kalichman et al., 2000a

N = 228

HIV-positive adults

Mean age: 40

 

Convenience sample

HIV clinics, AIDS service organizations, social service agencies

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection Method

Health-Related Outcome Associations

TOFHLA

Charlson Comorbidity Index

SF-12 Questionnaire

Inadequate health literacy was significantly associated with greater comorbidity burden, and this association remained after adjusting for confounders.

Inadequate functional health literacy was not related to health status after adjusting for confounders.

TOFHLA

Questionnaire or interview

Participants with lower health literacy were significantly less likely than those with higher health literacy: to report an undetectable HIV viral load, to indicate that they understand the meaning of viral load and CD4 cell counts, to state that their doctors ask their opinions about treatment, and to state that their doctors explain things to them so they understand.

Participants with lower health literacy were significantly more likely than those with higher health literacy: to visit a doctor at least once per month, to believe that HIV medications reduce HIV-transmission risk, to believe that it is safe to have sex if an HIV+ person has an undetectable viral load, to state that new HIV treatments make it easier to relax about unsafe sex, and to state that they practice more unsafe sex because of new treatments.

Health literacy level was not related to CD4 cell counts, amount of time since learning of HIV status, number of HIV-related symptoms, having diagnosed AIDS-related conditions, use of anti-HIV therapies, and some measures of treatment optimism.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Kalichman and Rompa, 2000

N = 339

HIV-positive adults

Mean age: 40

Convenience sample

HIV clinics, AIDS service organizations, social service agencies

Kalichman et al., 1999

N = 182

HIV-positive adults

Mean age: 39.1

Convenience sample

HIV clinics, AIDS service organizations, social service agencies

Kaufman et al., 2001

N = 61

First-time mothers aged 18 years or older who spoke English as their first language and had an infant between 2 and 12 months

Convenience sample

Public health clinic

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection Method

Health-Related Outcome Associations

Reading comprehension section of TOFHLA (lower literacy defined as scoring at or below 80%, higher literacy as scoring above 80%)

Questionnaire or interview

HIV-infected participants with lower health literacy had lower CD4 cell counts, higher viral loads, were less likely to be taking antiretroviral medications, reported a greater number of hospitalizations, and reported poorer health than those with higher health literacy. After adjusting for years of formal education, lower health literacy was associated with poorer knowledge of one’s HIV-related health status, poorer AIDS-related disease and treatment knowledge, and more negative health-care perceptions and experiences.

Adapted reading comprehension section of TOFHLA (lower defined as scoring 85% or below, higher literacy as scoring above 85%)

Interview

Questionnaire/survey

Participants with fewer years of education literacy and lower health literacy were significantly more likely to be non-adherent in the past 2 days than those with higher health literacy, and this association remained after controlling for age, ethnicity, income, HIV symptoms, substance abuse, social support, emotional distress, and attitudes toward primary care providers. Persons of low literacy were more likely to miss treatment doses because of confusion, depression, and desire to cleanse their body than were participants with higher health literacy.

REALM (higher health literacy defined as high school level or above, and lower health literacy as seventheighth-grade level)

Survey

Participants with higher health literacy were significantly more likely than those with lower health literacy to initiate and sustain breastfeeding during the first 2 months.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Lindau et al., 2002

N = 529

English-speaking patients older than 18 years

Median age: 27

58% African-American

18% Hispanic

91%

Prospective cohort

Ambulatory OBGYN clinic and a women’s HIV clinic

Moon et al., 1998

N = 543

Parents accompanying children to clinic

Mean age: 32

85.8%

Prospective cohort

Pediatric acute care clinic

Parikh et al., 1996

N = 202

Patients from Literacy in Health Care Study

Mean age: 41

92% African American

65%

Cohort

Emergency department and walk-in clinic, Atlanta, GA

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection Method

Health-Related Outcome Associations

REALM

Interview

Chart review

Physician survey

Health literacy level was the only factor independently associated with knowledge related to cervical cancer screening. This association remained after controlling for education, employment, ethnicity, insurance, and age.

Participants with inadequate and marginal health literacy were significantly more likely than those with adequate health literacy to: state that they would seek care for an illness in an emergency department or acute care facility (11% vs. 3%); not seek medical care if informed of an abnormal Pap test (30% vs. 19%).

REALM

Interview

REALM score significantly correlated with parental perception of how sick the child was. No relationship between REALM score and use of preventive services, comprehension of diagnosis, medication name and instructions, or ability to obtain and administer prescribed medicines.

TOFHLA

Survey

Interview

67.4% of participants with inadequate or marginal health literacy stated that they had trouble reading and understanding what they read. 39.7% of these participants acknowledged they have shame about their reading difficulty. Of the participants who had low functional health literacy and admitted having trouble reading, 67.2% had never told their spouses, and 53.4% had never told their children of their difficulties reading. Nineteen percent had never disclosed their difficulty reading to anyone.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Schillinger et al., 2003

N = 74

English-speaking patients with diabetes mellitus and low functional health literacy

Mean age: 64

85% non-white

(San Francisco General Diabetic Patients with Low Health Literacy Study)

71%

Cohort

2 primary care clinics, public hospital, San Francisco, CA

Schillinger et al., 2002

N = 408

English- and Spanishspeaking type-2 diabetes patients older than 30 years

(San Francisco General Diabetic Patients with Low Health Literacy Study)

91%

Cross-sectional

Two primary care clinics, public hospital, San Francisco, CA

Scott et al., 2002

N = 2,722

New Medicare enrollees between 65 and 80 years old

Mean age: 71

36%

Cohort

Prudential Medicare managed care (4 sites) Cleveland, Houston, Tampa, or South Florida

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection Method

Health-Related Outcome Associations

S-TOFHLA

Audiotaped patient-physician interaction

After a multivariate logistic regression, 2 variables were independently associated with good glycemic control among a group of diabetes patients with low health literacy: higher health literacy levels, and physicians’ use of an interactive communication strategy.

S-TOFHLA

Diabetes care profile social support scale

Short form of the Center for Epidemiologic Studies Depression Scale

Interview

Hospital database

After adjusting for patients’ sociodemographic characteristics, depressive symptoms, social support, treatment regimen, and years with diabetes, three variables were independently associated with HbA1c level: health literacy level, insurance status, and treatment regimen.

Patients with inadequate health literacy were less likely than those with adequate health literacy to achieve tight glycemic control and were more likely to have to report having retinopathy.

S-TOFHLA

Interview

Inadequate health literacy was independently associated with lower use of preventive health services including receiving the influenza and pneumococcal vaccinations, mammogram, or a Pap smear. This association remained significant after adjusting for demographics, years of school completed, income, number of physician visits, and health status.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Citation

Population

Participation Rate

Study Design

Setting

Shea et al., 2003

Published Abstract

N = 2,494

62% Hispanic

78% female

50% younger than 40

(Health Literacy and Patient Satisfaction Study)

Cohort

Urban community-based practices

Weiss et al., 1994

N = 402

Adult Medicaid enrollees

78.% Female

46% Hispanic

43% Caucasian

Mean age: 49

75%

Cohort

University Family Care, a healthcare organization Tucson, AZ

Williams et al., 1998a

N = 483

273 from emergency department Mean age: 37

210 from asthma clinic Mean age: 47

90%

Cohort

Emergency department and asthma clinic at urban public hospital, Atlanta, GA

Williams et al., 1998b

N = 516

402 patients with hypertension and 114 patients with diabetes

94% (Los Angeles)

86% (Atlanta)

Cohort

Two urban public hospitals in Los Angeles and Atlanta

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Data Collection Method

Health-Related Outcome Associations

S-TOFHLA

Interview

Consumer Assessment of Health Plans Survey (CAHPS) in 3 different formats: written, with supporting illustrations, and an automated telephone survey

Health literacy level was a significant predictor of reported satisfaction in all subscale and overall satisfaction scores, and this relationship remained when controlling for demographic factors and the type of CAHPS instrument given.

Instrument for the Diagnosis of Reading

University Famili Care Records

There was no significant relationship between literacy and health-care costs.

REALM

Interview

Observation of Metered dose inhaler (MDI) technique

Reading level was the strongest predictor of asthma knowledge score in a multivariate analysis. Poor MDI technique was found in 89% of patients reading at less than the third-grade level compared with 48% of patients reading at the high school level. Reading level was the strongest predictor of MDI technique in multivariate regression analyses.

TOFHLA (in either English or Spanish)

Interview

Participants with inadequate or marginal functional health literacy and either hypertension or diabetes had significantly less knowledge of their disease than those with adequate functional health literacy. There were no significant relationships between health literacy and measures of outcome (blood pressure, or HbA1c level).

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

nation rates, although the numbers of literate women did not change and there was a 12 percent increase in the number of literate men. This study also suggests that health behaviors may improve as a result of changes in health-care delivery without improvements in individual literacy (Northrop-Clewes et al., 1998).

Financial Associations of Low Health Literacy

The limited information available suggests that limited health literacy may be associated with increased consumer, health provider, and the healthcare system costs. Weiss and colleagues (1994) initially found no association between literacy skills, as measured by grade-equivalent reading level, and total 1-year health-care charges in 402 randomly selected Arizona Medicaid enrollees. The relationship between costs incurred and reading level as assessed by the IDL in the 72 patients in the original sample who were not seeking prenatal care was reanalyzed since 330 patients in this study were receiving prenatal care that had a fixed cost. The health-care costs of the remaining 72 patients showed greater variation. Consistent with REALM scoring, which categorizes the lowest reading group as third grade and under, the authors divided the sample at grade 3. Patients with a reading level at or below third grade had mean Medicaid charges of $10,688, while patients who read above the third-grade level had mean charges of $2,891 (p = 0.025) (Weiss and Palmer, 2004).

Friedland (1998) presented an analysis of the association of literacy and health-care utilization using data from the Health Care Financing Administration,6 the NALS, and the Survey of Income and Program Participation. This estimate was derived from predicted levels of functional literacy and estimates of health-care use. Differences in health-care spending were estimated by comparing health-care utilization by people with a lower probability of having functional literacy skills to health-care utilization by people those with a higher probability of having functional literacy skills. Friedland suggested that the additional health-care resource attributable to inadequate health literacy (NALS Level 1) in 1996 was $29 billion if inadequate health literacy was equivalent to inadequate literacy, and would have grown to $69 billion if even half of the marginally literate (NALS Level 2) were also considered not health literate (Friedland, 1998). This estimate has been cited elsewhere and, while illustrating the depth of the problem of limited health literacy, does not directly address the issue of cost.7

6  

HCFA, now the Centers for Medicare & Medicaid Services.

7  

The committee thanks Robert Friedland, Ph.D., for his contributions to this section of the report.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Associations of patient literacy with health-care utilization were examined by Baker and colleagues (1998, 2002a). Two analyses showed that limited literacy patients have higher rates of hospitalization that may be associated with greater resource use. Of 979 patients seen in the emergency department of Grady Memorial Hospital (Atlanta) in 1994–1995, logistic regression showed that those with inadequate health literacy, as measured by the TOFHLA, were more likely to be hospitalized (31.5 percent) than patients with adequate health literacy (14.9 percent). The OR after adjusting for confounding variables was 1.69. The adjusted relative risk increased to 3.15 among patients with inadequate literacy who had been hospitalized in the previous year (Baker et al., 1998). More recently, Baker and colleagues (2002a) studied a prospective cohort of 3,260 Medicare managed care enrollees. Of the 29 percent of these patients hospitalized over a 2-year period, the risk of admission was inversely related to health literacy as measured by the S-TOFHLA. The adjusted relative risk of admission was 1.29 for those with inadequate literacy and 1.21 for those with marginal literacy; however, it should be noted that education was not controlled for in this study.

Jose, a Bolivian man in his early 30s, stayed after class one night so I could help him understand a hospital bill. He had been having bad headaches for some time. Thinking it was his only option for care, he had gone to the emergency department to get treatment. There he was told the headaches would clear up if he got glasses. He was charged $300 for this diagnosis (Singleton, 2002).

For the purpose of this Institute of Medicine report, the committee commissioned an examination of the expenditure data collected in association with the Baker et al. (2002a) study from David Howard, a health economist at Emory University.8 Using econometric regression techniques, Howard found that predicted inpatient spending for persons with inadequate health literacy, as measured by the S-TOFHLA, was $993 higher than that of persons with adequate health literacy. This difference fell to $450 after controlling for health status. It is not clear whether this control is appropriate as there may be a bidirectional relationship between literacy and health status. Emergency care costs incurred by individuals with inad-

8  

The information in this section is drawn from the background paper “The Relationship Between Health Literacy and Medical Costs,” commissioned by the committee from David H. Howard, Ph.D. The committee appreciates his contribution. The full text of the paper can be found in Appendix B of this report.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Finding 3-1 About 90 million adults, an estimate based on the 1992 NALS, have literacy skills that test below high school level (NALS Level 1 and 2). Of these, about 40–44 million (NALS Level 1) have difficulty finding information in unfamiliar or complex texts such as newspaper articles, editorials, medicine labels, forms, or charts. Because the medical and public health literature indicates that health materials are complex and often far above high school level, the committee notes that approximately 90 million adults may lack the needed literacy skills to effectively use the U.S. health system. The majority of these adults are native-born English speakers. Literacy levels are lower among the elderly, those who have lower educational levels, those who are poor, minority populations, and groups with limited English proficiency such as recent immigrants.

Finding 3-2 On the basis of limited studies, public testimony, and committee members’ experience, the committee concludes that the shame and stigma associated with limited literacy skills are major barriers to improving health literacy.

equate health literacy scores were higher than in patients with adequate literacy, while pharmacy expenses were similar in both groups and outpatient expenditures were lower. Although this Medicare managed care sample is not representative of the U.S. population as a whole, the results are consistent with previous reports that limited-literacy individuals make greater use of services designed to treat complications of disease and fewer services designed to prevent complications (Baker et al., 1998, 2002; Gordon et al., 2002; Scott et al., 2002).

These data suggest that patients with limited literacy may interact with a complex health-care system in ways that interfere with ideal utilization patterns and therefore could be more expensive. However, since the causal relationships between literacy and health-care utilization and cost have not been discovered, it is not possible to establish a valid cost figure for the impact of limited health literacy. If the magnitudes suggested by Howard and Friedland approach the actual costs, they clearly underscore the importance of addressing this risk factor from a financial perspective, in addition to health outcome implications. More research is needed to expand these limited results and move to a clearer estimation of these effects.

Finding 3-4 Two recent studies demonstrate a higher rate of hospitalization and use of emergency services among patients with limited literacy. This higher utilization has been associated with higher health-care costs.

Suggested Citation:"3 Extent and Associations of Limited Health Literacy." Institute of Medicine. 2004. Health Literacy: A Prescription to End Confusion. Washington, DC: The National Academies Press. doi: 10.17226/10883.
×

Finding 3-3 Adults with limited health literacy, as measured by reading and numeracy skills, have less knowledge of disease management and of health-promoting behaviors, report poorer health status, and are less likely to use preventive services.

Finding 3-4 Two recent studies demonstrate a higher rate of hospitalization and use of emergency services among patients with limited literacy. This higher utilization has been associated with higher health-care costs.

Recommendation 3-1 Given the compelling evidence noted above, funding for health-literacy research is urgently needed. The Department of Health and Human Services, especially the National Institutes of Health, the Agency for Healthcare Research and Quality, the Health Resources and Services Administrations, and the Centers for Disease Control and Prevention; the Department of Defense; the Veterans Administration; and other public and private funding agencies should support multidisciplinary research on the extent, associations, and consequences of limited health literacy, including studies on health service utilization and expenditures.

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To maintain their own health and the health of their families and communities, consumers rely heavily on the health information that is available to them. This information is at the core of the partnerships that patients and their families forge with today’s complex modern health systems. This information may be provided in a variety of forms – ranging from a discussion between a patient and a health care provider to a health promotion advertisement, a consent form, or one of many other forms of health communication common in our society. Yet millions of Americans cannot understand or act upon this information. To address this problem, the field of health literacy brings together research and practice from diverse fields including education, health services, and social and cultural sciences, and the many organizations whose actions can improve or impede health literacy.

Health Literacy: Prescription to End Confusion examines the body of knowledge that applies to the field of health literacy, and recommends actions to promote a health literate society. By examining the extent of limited health literacy and the ways to improve it, we can improve the health of individuals and populations.

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