Health and Safety Needs of Older Workers (2004)

For the most part, the information available on workplace injuries and illnesses or disorders is derived from employer injury and illness reports required by the Occupational Safety and Health Act (OSHA) and analyzed by the Bureau of Labor Statistics (BLS), U.S. Department of Labor. The BLS reported that a total of 5.2 million workplace injuries and illnesses or disorders were reported in private industry during 2001, the most recent year for which survey data are available from the BLS.¹ The injury and

illness or disorder rate of 5.7 cases per 100 equivalent full-time workers was the lowest rate since BLS began reporting in 1973 (Table A-11 in Appendix A presents incidence rates of occupational injuries and illnesses for private industry by selected case types, for 1973–2001). Of the 5.2 million total nonfatal injuries and illnesses or disorders, about 2.6 million (2.8 cases per 100 full time workers) were lost workday cases, requiring recuperation away from work or restricted duties at work, or both. These injuries and illnesses or disorders occur in a wide range of industries and occupations (see Table 6-1) as a result of exposure to a wide range of hazards (see Table 6-2).

Of the 5.2 million nonfatal occupational injuries and illnesses or disorders in 2001, 4.9 million were injuries. Eight industries accounted for about 1.4 million injuries, or 29 percent of the total (see Table 6-3). There were about 333,800 newly reported cases of occupational illnesses or disorders

in private industry in 2001. Manufacturing accounted for more than 50 percent of these cases (Table A-12 in Appendix A presents BLS data indicating the number of nonfatal occupational illnesses by industry division and selected case types for 2001). Disorders associated with repeated trauma, such as carpal tunnel syndrome and noise-induced hearing loss, accounted

for 65 percent of the 333,800 total illness cases. Sixty-five percent of the repeated trauma cases were in manufacturing industries.

Of 2.6 million lost workday cases, 1.5 million required actual days away from work, while the rest resulted in restricted activity at work. Ten occupations accounted for nearly one-third of the 1.5 million lost workday cases that actually involved time away from work (Table A-13 presents BLS data indicating the number of nonfatal occupational injuries and illnesses involving days away from work by selected occupation and industry division for 2000). More than 4 out of 10 of these 1.5 million were sprains or strains, most often involving the back. (Table A-14 presents BLS data indicating the number of nonfatal occupational injuries and illnesses involving days away from work by selected injury or illness characteristics and industry division for 2000). Men accounted for nearly two out of three of the 1.5 million cases, a proportion somewhat higher than their share of the hours worked. The risk of workplace injury or illness or disorder varies substantially by industry and occupation (Table A-15 presents BLS data indicating incidence rates for nonfatal occupational injuries and illnesses involving days away from work per 10,000 full-time workers for selected character-

istics and industry division for the year 2000). For example, there is a tenfold difference in incidence rate for falls to a lower level between workers in finance, insurance, and real estate (4.2 per 10,000) and those in construction (40.0 per 10,000).

The U.S. Department of Labor defines work-related musculoskeletal disorders (WMSDs) as injuries or disorders of the muscles, nerves, tendons, joints, cartilage, and spinal discs, not including disorders caused by slips, trips, falls, or motor vehicle accidents. Unfortunately, the OSHA reporting system and the BLS survey do not have a single category for WMSDs. For example, cases caused by exposure to repetitive trauma, such as carpal tunnel syndrome (but not including back disorders), are grouped as illnesses together with occupational hearing loss. All back disorders, whether caused by repetitive trauma or sudden trauma, are grouped with injuries. BLS has estimated that when all WMSDs are aggregated they totaled more than 575,000 in 2000, more than 33 percent of all lost workday cases (U.S. Bureau of Labor Statistics, 2002).

A more detailed assessment of WMSDs has been undertaken by the Washington State Department of Labor and Industries, using worker compensation data. Of approximately 250,000 workers’ compensation claims accepted every year in Washington State, more than 65,000 or nearly 30 percent were for nontraumatic, soft-tissue WMSDs. The annual medical and wage replacement costs for these claims is more than $410 million, with additional indirect costs increasing the total impact to $1 billion. While these problems have been identified in substantial numbers in all industry sectors, industries can be rank ordered by the rate and number of WMSDs to determine where the greatest impacts and opportunities for prevention exist. Those industries with the highest combined ranking of WMSD rates and numbers include nursing homes, trucking and courier services, masonry, carpentry, roofing, concrete work, sawmills, and grocery stores. The highest risks are in those industries characterized by manual handling and forceful, repetitive exertions (Washington State Department of Labor and Industries, 2000, 2002). The National Research Council report (2001), Musculoskeletal Disorders in the Workplace, provides informative detail on the topic.

Over the past several years there have been approximately 6,000 fatalities annually from workplace injuries as counted by the BLS Census of Fatal Occupational Injuries (CFOI).² The numbers and risks vary by industry and

FIGURE 6-1 Rate of workplace fatal injuries, 2001.

SOURCE: Bureau of Labor Statistics

occupation (see Figure 6-1). The number and rate of workplace fatalities have been declining steadily for more than 40 years. However, the longest continuous data series is limited to death certificate information and only dates back to 1980 (see Figure 6-2). The most complete data are from CFOI but only date back to 1992 (see Figure 6-3).

This summary of occupational injury and illness or disorder reporting should be placed in the context of the generally accepted understanding that workplace injuries and illnesses or disorders are substantially underreported. For example, the BLS survey measures the number of work-related illness or disorder cases that are recognized and reported by employers during the year, but long-term latent illnesses or disorders caused by chemical exposure are difficult to relate to the workplace and are not adequately recognized. Gaps in the training and awareness of medical pro-

viders contribute to underreporting. There are also significant disincentives to reporting workplace problems. For medical providers these include reluctance to participate in contentious workers’ compensation proceedings. For workers these include fear of discrimination and income loss.

Several studies have found this underreporting to be of significant magnitude. A National Research Council panel evaluated the BLS system for occupational injury and illness or disorder reporting in 1987 and concluded that it had significant shortcomings for both statistical and administrative purposes (National Research Council, 1987). While noting substantial reasons and incentives for underreporting, particularly with regard to long-latency occupational illness or disorder, the panel was unable to determine the extent of reporting errors. The panel found it startling that the nation did not even have an agreed method to estimate a phenomenon as basic as traumatic death in the workplace. The subsequent development of the BLS CFOI system to count these traumatic deaths addressed this, but most of the other sources of underreporting have yet to be corrected.

There are a number of factors that might result in underreporting of occupational injuries and illnesses or disorders. Those who experience economic insecurity appear to have increased concern about job loss (Minter, 1996). Union membership among nonagricultural employees has been falling (Dunlop, 1994; Hirsch, Macpherson, and Vroman, 2001; BLS, 2002). Contingent work has been growing, and the U.S. General Accounting Office (GAO) estimated that by the year 2000, contingent workers comprised 30 percent of the country’s workforce (GAO, 2000). The growing immigrant worker population includes those lacking documentation (Schmitt, 2001). Few reliable data are available on the growth of traditional safety incentive programs. Medical diagnosis of occupational illness or disorder depends on access to medical care, which has been declining among the workforce (Hoffman and Schlobohm, 2000; Holahan, 2000). Landrigan and Baker (1991) estimated that there are 50,000 to 70,000 deaths yearly from workplace diseases and that these are typically not correctly diagnosed because they mimic nonoccupational illnesses or disorders and because most physicians are not adequately trained to recognize them. Biddle and colleagues (1998) concluded that workers’ compensation databases also undercount workplace illness, estimating that between 9 percent and 45 percent of workers with known or suspected cases actually file for benefits. Acute conditions were no more likely to lead to claims than chronic conditions with long latency. Rosenman et al. (2000) similarly found that workers’ compensation claims were filed by only 25 percent of workers whose WMSDs had been reported by physicians according to the Michigan State occupational disease reporting law.

Most recently Azaroff and Levenstein (2002) have evaluated obstacles to the reporting of occupational injuries and illnesses in the BLS survey,

workers’ compensation systems, employer medical programs, and physician reporting systems. They identify numerous barriers (filters) to reporting in each of these systems and note that these barriers “particularly block documentation of health problems affecting populations especially vulnerable to workplace hazards, including immigrant and low-wage workers.” None of these analyses, however, specifically address reporting among older workers.

The BLS undertook an evaluation of current injury and illness reporting in an effort to understand the declining trend in injury and illness reports (Conway and Svenson, 1998). This analysis did not suggest that rates fell because of a shift in industry composition of the labor force, but it did note that major legislative changes in workers’ compensation systems at the state level may have had an effect on reports of injuries. They suggested on the basis of anecdotal evidence that the trend may result from increasing awareness and recognition of occupational hazards among all parties. At about the same time, the BLS commissioned an annual audit of its own reporting system (Lexington Group and Eastern Research Group, 2002). The results suggest that over the four-year period, there have been generally consistent results with over 90 percent of the sample providing accurate reports. In this administrative audit, employer reports to OSHA were matched with internal company records. Consequently no interviews with workers are reported, nor is there an effort to develop independent estimates of occupational injury and/or disease. A comprehensive analysis of the trend in injury reporting, therefore, has yet to be done.

Workers 45 years and older accounted for 494,000 of the 1.6 million lost workday cases reported by BLS for the year 2000 (30 percent of the cases and 32 percent of the hours worked; Table A-16 presents BLS data indicating the number of nonfatal occupational injuries and illnesses involving days away from work, by selected worker characteristics and industry division for the year 2000). While the numbers of cases among workers less than 45 years old dropped steadily from 1992 to 2000, the number of cases among older workers slowly rose over the same period (see Figure 6-4). Also, the median duration of absence from work due to a work injury increased consistently with age, from 4 days among those age 24 and younger to 10 days for those age 55 and older (BLS, 1996). BLS identified two reasons for this age differential. First, a higher proportion of injuries among older workers are more severe in nature; fractures, for example, make up 11 percent of injuries among workers 55 years and older but only 5 percent of injuries among workers under age 55. Second, for the same

FIGURE 6-4 Number of lost workday injury and illness cases by age group in the years 1992–2000.

SOURCE: Bureau of Labor Statistics.

condition older workers lose more workdays; fractures result in a median 30-day absence among older workers but 18 days among younger workers.

Assessment of differences in employment and employment characteristics over time could contribute to a better understanding of the changes in rates of workplace injuries and age. Current BLS data reports lack adequate denominator information for this purpose although it has been demonstrated that application of CPS age-specific employment information could be used to estimate rates for many BLS data now available only as counts (Ruser, 1998). A complementary system of self-reported work-related injury data is provided by the National Center for Health Statistics annual surveys, the National Health Interview Survey in particular. Detailed information about work and work exposures, however, has only been collected once (1998). The NHIS 1988 supplement provided a single snapshot of data; changes in employment and risk patterns should be followed prospectively to provide information about whether, for example, the increased number of cases among older workers is due to increased numbers of older workers, or whether older workers are exposed to more or different workplace hazards now than previously.

Although WMSDs are the most common work-related disorders, little is known about their age distribution. Numbers of WMSDs (but not rates) by age and industry are available from the Washington State workers’ compensation system (Table A-17 presents a summary of workers’ compensation claims for work-related musculoskeletal disorders for Washington

State, from 1992 through 2000). Twenty-two percent of the WMSD claims occur in workers age 45 and older, ranging from 17 percent in construction to 37 percent in public administration. The greatest number of claims among those age 45 and older was in the service sector, with 23,612 claims for the years 1992–2000. This was 29 percent of all claims in this older age group, only slightly greater than the 26 percent of claims among all ages for this sector. Only for public administration was the percentage of claims among the older workers (7.6 percent) substantially greater than the percentage of claims among all workers (4.5 percent).

In 2001, 2,665 or 45 percent of the 5,900 total fatalities counted by CFOI were accounted for by the 35 percent of all workers who were 45 years or older (Table A-18 presents BLS data indicating the number and percentage of occupational injuries, by selected worker characteristics, for 2001). The fatal injury rate is higher for self-employed than for wage workers, and differences increase with age (Personic and Windau, 1995).

Older workers experience relatively high rates of workplace fatality and high injury severity compared with younger workers (Kisner and Pratt, 1999; Myers et al., 1999). A recent analysis (Bailer et al., 2003) of the National Traumatic Occupational Fatality database confirmed that the rates of fatal occupational injuries increase with age and noted that this trend is especially marked for machinery related fatalities. Agnew and Suruda (1993) noted that the rates of work-related fatal falls increased among older workers and that a relatively large percentage of these fatalities were associated with the use of ladders. Possible reasons include enhanced susceptibility, lower baseline function, or the effects of cumulative exposures.

Older workers also experience relatively low overall rates of work-related injury and illness or disorders compared with younger workers. The reasons for this are not entirely clear but possible explanations include experience and expertise, motivation, and survivor or healthy-worker effects.

The prevalence of disability in the workforce has long been known to increase with age (Kraus and Stoddard, 1991; Blanck et al., 2000). The National Health Interview Survey (1994) shows that the percentage of workers with work-limiting disabilities increases with age, starting at 3.4 percent for workers aged 18 to 28 years, increasing to 8.4 percent for workers aged 50 to 59, and to 13.6 percent for workers aged 60 to 69. The increased prevalence of impairments among older workers and the growth of our older workforce will increase the number of workers who bring impairments into the workforce with them.

This increased prevalence of impairments among older workers is of concern because of recent research (Zwerling et al., 1997, 1998; Zwerling, Sprince et al., 1998) suggesting that workers with a broad spectrum of impairments are at higher risk for occupational injuries. This increased risk was seen among older workers in the Health and Retirement Study

(Zwerling et al., 1998; Zwerling, Sprince et al., 1998), as well as among workers of all ages surveyed in the National Health Interview Survey (Zwerling et al., 1997). Similar results were recently found among Taiwanese workers as well (Chi, Chen, and Lin, 2001).

In the United States, controversy over the risk of injuries to older workers dates back at least to the 1920s, when a purported increased risk of occupational injuries among older workers was used as justification to exclude them from the workforce (Kossoris, 1940). Using data from the states of Wisconsin and New York as well as from Switzerland and Austria, the BLS (Kossoris, 1940) concluded that “older workers were injured less frequently than younger workers; but once injured, they experienced proportionately more deaths and permanent impairments than did younger workers. Similarly, their healing periods in temporary disability were, on the average, longer.” Although these data had a number of limitations—underreporting of injuries, absence of occupational data, and inaccuracy of reported ages, to name just three—the results have stood the test of time.

Over the years, substantial data have accumulated suggesting that older workers have a decreased risk for nonfatal occupational injuries than that of their younger colleagues. This has been seen both in national databases (Root, 1981; Leigh, 1986) as well as in studies of single industries (Mueller et al., 1987; Jensen and Sinkule, 1988; Oleske et al., 1989). In the 1988 National Health Interview Survey Supplement on Occupational Health and Safety, men 50 years of age and older averaged 2.65 lost workday injuries per 100 person-years compared to men aged 30–49 years who averaged 5.78 per 100 person-years (Landen and Hendricks, 1992). In part, this difference may be related to differences in occupations of younger and older workers. Mitchell (1988) addressed this issue in a multivariate analysis of U.S. national data. She found that for injuries causing only temporary disability, 81 percent of the variance was explained by occupation, but age explained 11 percent of the variance after accounting for occupation and industry. A recent review of the literature (Laflamme and Menckel, 1995) concluded that older workers have a lower risk of nonfatal occupational injuries than that of their younger colleagues.

Pransky et al. (2000) reviewed possible explanations for the lower rate of occupational injuries among older workers. These included increased experience, safer behavior, and less physically demanding jobs. They also considered potential reporting bias, with some occupational injuries being attributed to nonoccupational causes by worker health care providers. However, the literature provides little evidence to support any of these explanations.

Although older workers are less likely to be injured at work, there is considerable evidence to suggest that the consequences of those injuries are greater than those suffered by younger workers. Since 1940 (Kossoris), the

BLS has reported evidence that older workers had longer periods of disability than their younger colleagues. More recent data (Personick and Windau, 1995; BLS, 1996) show that the median number of workdays lost per occupational injury increases monotonically from 4 at age 20 to 10 at age 55 and over (see Figure 6-5). Since this prolonged disability can be seen in specific industries as well as across broader jurisdictions, it is not likely that it can be explained by industry, occupation, or specific job exposures (Laflamme and Menckel, 1995; Landen and Hendricks, 1992; Kossoris, 1940). The most frequently mentioned explanation for the difference in duration of disability has been a presumed decrease in recuperative powers among older workers (Personick and Windau, 1995; Nicholson, 1995). The prolonged period of disability among injured older workers suggests the importance of return-to-work programs to hasten the recovery of these older workers.

Although occupational injuries are less common among older workers, when they do occur they are more likely to result in death than among younger workers. This was clear in the statewide databases of the 1930s (Kossoris, 1940), and it is still seen in the National Traumatic Occupational

FIGURE 6-5 Median days away from work due to workplace injury, 2000.

SOURCE: U.S. Bureau of Labor Statistics, Issues in Labor Statistics, April 1996.

Fatality database (Kisner and Pratt, 1997) and in the Census of Fatal Occupational Injuries (Personick and Windau, 1995). In the 1980s, workers aged 65 years and older had a workplace fatality rate 2.6 times that of workers aged 16 to 64. Using a multivariate analysis, Mitchell (1988) found that 80 percent of the variance in occupational fatalities was related to age, even when occupation and industry are entered in the model.

Downsizing has been associated with increased rates of fatal occupational injuries in the United States (Richardson and Loomis, 1997) and absenteeism in Finland. In the health care industry, studies have suggested that downsizing, understaffing, and stress (American Nurses Association, 1995) are associated with occupational injuries among nurses (Shogren and Calkins, 1997) and back injuries among aides in nursing homes (Service Employees International Union, 1995; Institute of Medicine, 1996). Needle-stick injuries have been associated with organizational restructuring that increases stressful working conditions in U.S. hospitals (Aiken and Fagin, 1997) and with understaffing and poor organizational climate (Clarke, Sloane, and Aiken, 2002). Thirty-nine percent of nurses are 45 years of age or older (Dohm, 2000).

A higher incidence of injury and illness has been reported among sub-contractors (Quinlan and Mayhew, 2000). For example, the outsourcing of maintenance in the U.S. petrochemical industry has led to serious safety and health problems, including several catastrophic explosions (Rebitzer, 1995). In Australia, outsourced (largely home-based) garment workers reported three times more injuries and more work-related violence than those working in factories. In addition, self-employed workers, especially those in agriculture, road transport, and construction, face a significantly higher risk of serious injury or death (Quinlan and Mayhew, 2000). A study in Finland also observed a greater risk of mortality among temporary employees compared with permanent employees, primarily from alcohol-related causes and, for men, smoking-related cancer (Kivimäki et al., 2003).

Extended work hours have been associated with work accidents and injuries (Daltroy et al., 1991; Hanecke et al., 1998; Leigh, 1986; Lowery et al., 1998; Spurgeon, Harrington, and Cooper, 1997). For example, Hanecke et al. (1998), examining 1994 national German injury data, found a greatly increased injury risk beyond the ninth hour at work during a workday. For evening and night shifts, risk increased greatly past the eighth hour of work. Similarly, Lowery et al. (1998), examining data from construction contracts at Denver International Airport, 1990–1994, found that contractors with overtime payrolls had a two to three times higher injury rate than those without overtime payrolls. Recent reviews of studies on organiza-

tional factors have found lower injury rates to be associated with empowerment of the workforce; good relations between management and workers (Hale and Hovden, 1998; Shannon, Mayr, and Haines, 1997); autonomy; efficacy; delegation of control; low stress; low grievance rates (Hale and Hovden, 1998); and encouragement of long-term commitment of the workforce (Shannon et al., 1997).

Musculoskeletal injuries and pain have been associated with organizational downsizing in Finland (Vahtera, Kivimaki, and Pentti, 1997), reengineering in a Canadian hospital (Shannon et al., 2001), low staff density combined with high nursing-unit workloads (Larese and Fiorito, 1994; Yassi et al., 1995), lean production in the automobile industry in the United States and Canada (Landsbergis, Cahill, and Schnall, 1999), contingent or temporary work (European Agency for Safety and Health at Work, 2002), and overtime work (Bergqvist et al., 1995; Bernard et al., 1994).

A substantial body of research has linked WMSDs to stressful aspects of work organization, such as machine-paced work, inadequate work/rest cycles, wage incentives, time pressure, overload, low job control, low social support, repetitive work, and lack of task variability (Ahlberg-Hulten, Theorell, and Sigala, 1995; Bergqvist et al., 1995; Bernard et al., 1994; Bongers et al., 1993; Kerr et al., 2001; Krause et al., 1997; Leino and Hanninen, 1995; Moon and Sauter, 1996; National Research Council, 2001; Warren, 2000; Warren et al., 2000). It has been suggested that the dramatic increase in the number of reported WMSDs in the United States, beginning in the mid-1980s, resulted in part from work intensification. For example, the U.S. meat packing industry, in response to global competition, had increased line speed, introduced machine pacing, and fragmented jobs (Novek, Yassi, and Spiegel, 1990), which contributed to dramatic increases in WMSDs (National Institute for Occupational Safety and Health [NIOSH], 1994).

The NIOSH Musculoskeletal Disorders Working Group has determined that “research is needed in the areas of task assignment and work/rest schedules, job rotation, job enlargement, and length of the workday” (NIOSH, 2001:11) and has called for studies on “the impact of downsizing, labor shortages, or increased overtime on the occurrence of MSD” (NIOSH, 2001:17). Additional evidence for the importance of such research comes from studies of the effects of long-term employment in piecework jobs. Garment workers in Quebec were found to have a doubling of risk of severe disability associated with employment for more than five years in jobs paid according to a piecework system. The association was strongest for disability due to musculoskeletal disorders but also present for cardiovascular disease (Brisson et al., 1989; Brisson, Vezina, and Vinet, 1992). Vineyard workers in France were found to have a doubling of risk of hand

paresthesias associated with piecework paid jobs in vine pruning (Roquelaure et al., 2001).

Downsizing has also been associated with minor psychiatric disorders among English male government employees (Ferrie et al., 1998). Long work hours have been associated with psychological distress, including burnout (Spurgeon et al., 1997), psychological symptoms (Sparks et al., 1997), and unhealthy behaviors (Westman, Eden, and Shirom, 1985).

The International Labour Office (ILO) of the United Nations recently reported on workplace mental health issues in Finland, Germany, Poland, the United Kingdom, and the United States. It noted that “in all five countries, the incidence of mental health problems [particularly depression] has risen in the past decade [and] … while the origins of mental instability are complex and the workplace practices and income and employment patterns differ widely among the countries studied, a number of common threads appear to link the high prevalence of stress, burnout, and depression to changes taking place in the labor market, due partly to the effects of economic globalization” (Gabriel and Liimatainen, 2000:4).

The strongest evidence that recent trends in working life may be having an impact on workers’ health comes from studies of chronic diseases, such as cardiovascular disease (CVD), CVD risk factors such as blood pressure (BP), and the job characteristics and job schedules that are associated with CVD and BP. CVD is the number one cause of morbidity and mortality in the United States (American Heart Association, 1998). Hypertension in the United States is very common, with a prevalence of about 75 percent among African Americans and 50 percent among whites aged 60–74. The cost of work-related CVD in the United States is estimated at $10 to $20 billion annually (Leigh and Schnall, 2000).

We commonly label chronic diseases or conditions (e.g., hypertension, CVD, adult-onset diabetes), as diseases of aging, implying that they result from some natural biological process. However, essential hypertension (the 95 percent of hypertension cases without an organic cause such as kidney disease), adult-onset diabetes, and heart disease are quite uncommon in nonindustrialized populations (Carvalho et al., 1989; Cooper, Rotimi, and Ward, 1999). A major cross-cultural study of adult BP in 84 groups worldwide found virtually no rise in BP with age and no hypertension among hunter-gatherers, herders, or traditional family farmers (Waldron et al., 1982). This study also found substantial (r = 0.46–0.67) and significant associations between BP and involvement in a money economy even after controlling for salt consumption and, for men, after controlling for body mass index (BMI) (Waldron et al., 1982).

Such studies suggest that the primary causes of these diseases are stressful living and working conditions, shaped by a socioeconomic status hierarchy in developed societies. Therefore, prevention of these diseases, or ac-

commodation of older workers who have these diseases, involves identifying and altering those conditions.

Few studies have examined the effect of new organizational practices on cardiovascular outcomes. Danish bus drivers transferred to another bus company showed increases in urinary cortisol, glycated hemoglobin, and systolic BP at work during the year following transfer (Netterstrom and Hansen, 2000). In a study of English male government employees, downsizing was associated with increases in BP (Ferrie et al., 1998). However, other studies have shown only temporary increases in BP following reorganization (Pollard, 2001) or downsizing (Schnall, Landsbergis et al., 1992).

In contrast, a larger body of research exists examining the effect of task-level risk factors that have been increasing in prevalence: excessive work hours and stressful job characteristics. Job strain, defined as high psychological job demands and low job control (Karasek and Theorell, 1990), is the most widely studied job stressor; it has been increasing in prevalence in Europe in the past decade (European Foundation, 1997) and may be increasing in the United States. As of 2000, there have been 24 studies of job strain and CVD among men (Belkic, Landsbergis et al., 2000), and six studies among women (Brisson, 2000), most with significant positive associations. Some studies, while not examining the full demand/ control model, have shown that low job control predicts cardiovascular disease (Bosma, Peter, Siegrist, and Marmot, 1998). There is also evidence that low control in the workplace increases risk of depression (Stansfeld et al., 1999) and rates of sickness absence (North et al., 1996).

The link between job strain and CVD appears to be mediated in part by BP. While few studies of job strain and casual clinic BP have shown significant associations (Schnall, Landsbergis, and Baker, 1994), strong evidence of an association is found in studies where BP is measured by an ambulatory (portable) monitor (Belkic, Schnall, and Ugljesic, 2000). Ambulatory BP (AmBP) is a better predictor of target organ damage and CVD than is casual clinic BP (Verdecchia et al., 1999). Most cross-sectional studies of job strain and AmBP in men (Belkic, Landsbergis et al., 2000) and in women (Brisson, 2000) show significant positive associations, with an effect of job strain in the range of 4–8 mm Hg systolic AmBP. In the only longterm prospective study of job strain and AmBP, New York City men with chronic exposure to job strain over three years had 11 to 12 mm Hg higher systolic work AmBP than the group unexposed at both times (Schnall et al., 1998). In addition, those reporting job strain at entry into the study but no job strain three years later exhibited a significant decrease in systolic AmBP of 5.3 mm Hg at work and 4.7 mm Hg at home (Schnall et al., 1998). This decrease suggests that early detection and prevention strategies should be effective, especially for older workers who are more likely to have elevated BP.

On-the-job BP monitoring while employees are working holds promise as a surveillance technique to detect hidden work-related hypertension, characterized by normal casual clinic BP and elevated work BP (Schnall and Belkic, 2000). Such surveillance programs can trigger both individual treatment and workplace prevention programs for older workers, including job redesign (Belkic et al., 2001). Siegrist’s (1996) effort-reward imbalance model has as its basis the notion of reciprocity: appropriate reward for effort expended. Reward may be income, esteem (including self-esteem), and status, including career opportunities. The hypotheses is that emotional distress that accompanies inadequate reward for effort expended activates biological pathways that increase risk of cardiovascular disease. The effort-reward imbalance model relates not only to a particular workplace, but also to the operation of the labor market. Careers may be blocked, and hence rewards diminished, by lack of occupational opportunity in the labor market. Studies in Sweden (Peter et al., 2002) and the United Kingdom (Bosma et al., 1998) have shown that low control and effort-reward imbalance are independently related to coronary heart disease. The Whitehall II study has shown that effort-reward imbalance is related to functioning, using the SF-36 measure (Stansfeld et al., 1998).

A number of studies have suggested that long working hours may increase the risk of heart disease (Alfredsson, Spetz, and Theorell, 1985; Russek and Zohman, 1958; Theorell and Rahe, 1972; Falger and Schouten, 1992; Liu, Tanaka, and The Fukuoka Heart Study Group, 2002; Sokejima and Kagamimori, 1998). Two recent Japanese studies also found evidence linking overtime work with elevated BP among men working more than 55 hours per week (Hayashi et al., 1996; Iwasaki et al., 1998), with the second study finding an association only among men greater than 50 years old.

Increased risk of CVD has also been seen in threat-avoidant vigilant work (Belkic et al., 1992). For example, professional drivers, particularly urban transport operators, have been consistently found to have high risk of CVD and hypertension (Belkic, Emdad, and Theorell, 1998). Fifty-four percent of all U.S. bus drivers are 45 years of age or older (Dohm, 2000).

The amount of CVD that can be attributed to work stressors may be substantial. Conservative estimates of population-attributable risk (PAR percent) are 7 to 16 percent in Sweden (Karasek and Theorell, 1990) and 6 to 14 percent in Denmark (Kristensen, Kronitzer, and Alfredsson, 1998). Based on data from the New York City blood pressure study, roughly 25 to 40 percent of hypertension among men can be attributed to work stressors (Landsbergis et al., 1994). Few studies have examined the combined or synergistic effect of workplace stressors along with other work exposures.

The effect of job strain is more consistent and stronger for blue-collar men than for men with higher socioeconomic status (SES), both for CVD (Belkic, Landsbergis et al., 2000) and BP (Landsbergis et al., 2003). Among

women, similar (though not completely consistent) patterns were seen in the Framingham Heart Study (Eaker, Pinsky, and Castelli, 1992; Eaker, Packard, and Thom, 1989; Haynes and Feinleib, 1980; LaCroix, 1984). These findings suggest that increased efforts at early detection and prevention of work-related CVD and hypertension are especially required among lower SES workers. There has been a large decline in the death rate from CVD over the past 40 years in the United States (Liao and Cooper, 1995), and studies suggest that CVD incidence was also declining during the 1960s and 1970s (Elveback, Connolly, and Melton, 1986; Gillum, Folsom, and Blackburn, 1984; Pell and Fayerweather, 1985). However, more recent U.S. studies show little or no decline in CVD incidence over the past 20 years (Derby et al., 2000; Goldberg et al., 1999; Kostis et al., 2001; McGovern et al., 2001; Rosamond et al., 1998, 2001). There has been remarkable progress in treating CVD (and reducing mortality), but little recent success in preventing this disease.

This is surprising given declines in the prevalence of smoking and cholesterol levels (Johnson et al., 1993; Sytkowski et al., 1996). There is conflicting evidence regarding trends in the prevalence of hypertension (Brody, 1994; Burt et al., 1995; Kannel, Garrison, and Dannenberg, 1993). While some risk factors, such as obesity and diabetes, are increasing in prevalence (Harris et al., 1998; Kuczmarski et al., 1994), there is increasing recognition that psychosocial stressors may also be contributing to maintaining stable CVD rates (Gornel, 1999).

In the context of declining mortality rates for all SES groups, there is a growing gap between higher and lower SES groups in the United States in death rates from all causes, according to data from 1959 through 1996 (Steenland, Henley, and Thun, 2002) and death from CVD, according to data from 1969 through 1998 (Singh and Siahpush, 2002). For example, for men 45 years or older, the disparity in heart disease mortality rates between the highest and lowest educational groups during 1959 to 1972 was only 22 percent but rose to 62 percent during the 1982 to 1996 period. For women 45 years or older, the disparity rose from 48 percent during 1959 to 1972, to 73 percent during 1982 to 1996 (Steenland et al., 2002). There are no U.S. data on incidence of CVD by social class; however, growing SES differences in incidence of heart disease have been observed in Sweden between 1971 and 1994 (Hallqvist et al., 1998) and in Denmark between 1981 and 1993 (Tuchsen and Endahl, 1999).

Since chronic diseases such as CVD and hypertension take years to develop, we may only be observing the initial stages of the health impact of increasingly stressful working conditions. Further research is needed to test the hypothesis that increasingly stressful job characteristics, especially among lower SES workers (Vogel, 2002), and increasing income inequality

may be contributing to the observed increases in health inequality and to the failure of CVD rates to decline.

Karasek’s job demands-control model of work stress also describes the adult socialization of personality traits and behavior patterns that occur at work. Chronic adaptation to low-control/low-demand situations (passive jobs) can result in reduced ability to solve problems or tackle challenges (Karasek and Theorell, 1990), feelings of depression (Karasek, 1979), and learned helplessness. Conversely, when high (but not overwhelming) job demands are matched with greater authority and skill, more active learning occurs, enabling individuals to develop a broader range of coping strategies. For example, decreases in smoking prevalence were observed among New York City men whose job control increased over three years (Landsbergis et al., 1998). In Sweden, workers whose jobs became more passive over six years reported less participation in political and leisure activities. In contrast, workers in jobs that became more active participated more in these activities (Karasek and Theorell, 1990). In the United States, increased intellectual flexibility, nonauthoritarianism, capacity to take responsibility for one’s actions, and participation in intellectually demanding leisure time were observed among workers with greater occupational self-direction, a concept similar to decision latitude (Kohn and Schooler, 1982). These findings were replicated in 20 years of follow-up, with an effect significantly greater among older workers (Schooler, Mulatu, and Oates, 1999). Similarly, participation in complex leisure-time activities increases intellectual functioning among older workers (Schooler and Mulatu, 2001).

There is “a substantial amount of evidence documenting the continued learning capacity of older workers…. Interventions designed to increase the feelings of self-direction and the control of older persons (such as teaching them effective coping skills) result in improved cognitive problem-solving ability…. In terms of the workplace, efforts to enhance the autonomy and decision latitude of older workers might well result in heightened levels of psychological well-being and performance” (Robertson and Tracy, 1998:89). “Jobs that are stimulating or that enhance skill development over time may positively affect productivity, while jobs that are simple or highly routine may over time produce workers who are unchallenged, bored and eventually poor performers” (Robertson and Tracy, 1998:89; Avolio and Waldman, 1987). In a prospective study of a representative sample of Danish employees, early retirement was predicted not only by ergonomic exposures, but also by poor possibilities for development at work, mediated by monotonous repetitive work (Borg, Burr, and Christensen, 1997). Thus,

work organization acts not only as a potential source of stress and increased disease risk for older workers, but also potentially as a key factor in the promotion of physical and mental health and the development of creative potential, effective coping, and social involvement outside work.

There is limited evidence that physical workplace stressors can impact the health of older workers to a greater extent than younger workers. For example, shiftworkers over 40 years of age seem to sleep worse than younger workers after night (but not after morning) shifts (Haermae, 1996). There is also limited evidence that psychosocial workplace stressors can produce an even greater risk of injury and illness or disorders among older workers than younger workers. For example, in Finland, the effect of downsizing on absenteeism and musculoskeletal disorders was found to be greater for older workers than younger workers (Vahtera et al., 1997).

Older workers also appear to be less likely to tolerate tight time constraints and assembly work (Molinie and Volkoff, 1994). In a New York City study, the effect of job strain on ambulatory blood pressure (AmBP) was greater among men aged 51–60 (15 mm Hg) and 41–50 (9 mm Hg) than among 31- to 40-year-old men (Schnall, Schwartz, Landsbergis, Warren, and Pickering, 1992). Similarly, in a Japanese study of white-collar men, an effect of overtime on BP was seen only in men over 50 years old (Iwasaki et al., 1998). These studies are consistent with an effect of cumulative lifetime exposure to work stressors (represented by age). A less likely alternative explanation is that older workers are somehow more vulnerable to the effects of work stressors, independent of their previous work-life exposures. This question needs to be resolved through further research.

Older workers may find some job schedules and characteristics more challenging, such as night work, tasks that rely heavily on working memory, muscular strength and joint flexibility, or require high levels of cardiovascular fitness, fast reaction times, and fast information processing (Griffiths, 1997). Such tasks could result in performance deficits in older people, as well as an increased risk of accidents or other acute or chronic health problems (Czaja and Sharit, 1993; Haermae, 1996). Thus, “any efforts to keep older people at work will clearly have to pay particular attention to minimizing work stress, musculoskeletal disorders and cardiovascular disease” (Griffiths, 1997:199), which are common conditions experienced by older workers (Ilmarinen, 1997; Tuomi, Ilmarinen, Martikainen, Aalto, and Klockars, 1997).

In contrast to the BP studies cited above, studies of job strain and CVD have provided mixed findings when stratified by age. Some studies do find stronger associations of job strain among older workers and CVD among

older Swedish white-collar men (Johnson, Hall, and Theorell, 1989); coronary heart disease (CHD) symptoms among older Swedish white-collar workers (Karasek, 1990); and CHD among older Framingham, Massachusetts women (LaCroix, 1984).

However, two case control studies of myocardial infarction (MI) in Stockholm found a greater relative risk in younger workers: 40- to 49-year-olds versus 50- to 64-year-olds in one study (Alfredsson, Karasek, and Theorell, 1982) and 45- to 54-year-olds versus 55- to 64-year-olds in the other (Theorell et al., 1998). In the more recent Stockholm study (Theorell et al., 1998), decreasing job control during the three years preceding the MI was a much stronger risk factor in the 45–54 age group than in the 55–64 age group. The authors speculated that, in this younger group, “decreased job status could be seen as a major threat. Previous studies in industrialized countries have shown that working men can expect rising levels of decision latitude (Beilin and Puddey, 1993), especially during the first years of their working career. During the period after 55 years of age, this development is halted, and no further increase in decision latitude may then be expected in most men. When men are approaching retirement age, such a loss of status may not be perceived as equally threatening” (Theorell et al., 1998:387).

An important concept called work capacity or work ability has emerged from research in the Nordic countries. A recent review points out that the concept of work capacity requires that the productive potential of workers not be thought of only in terms of the capabilities of a person, but also in terms of the nature of the work itself, specifically work demands and other factors such as work content and work organization. This is an “innovative and promising line of research on the relationships among age, health, and the productivity of older workers” (Robertson and Tracy, 1998:91). The World Health Organization (WHO) conceptualizes work capacity as “a comprehensive term covering all the capacities necessary to perform a given type of work…[and] therefore including physical, mental, and social functioning capacities” (WHO, 1993:3).

The Finnish Institute of Occupational Health conducted the largest study of the work capacity of older workers, an 11-year follow-up (1981–1992) of 6,259 municipal workers, aged 44–58 at the beginning of the study (Tuomi, Ilmarinen, Martikainen et al., 1997). The researchers developed a work ability index (WAI) that “represents a composite of standard measures of health status, such as the number of diagnosed diseases and the number of sick days within the past year, in combination with more subjective measures, such as estimations of present work ability in relation to physical and mental work demands (as a function of the nature of the work itself) and personal psychological resources” (Ilmarinen, 1994, cited in

Robertson and Tracy, 1998:92). The WAI of this cohort in 1981 was a strong predictor of retirement on disability pension or death by 1992 (Tuomi, Ilmarinen, Seitsamo et al., 1997).

Work content, work environment, and work organization were found to predict accurately both the reported decline in work capacity and the observed rate of retirement due to disability over the first four years of the study (Ilmarinen, 1994). Demanding physical features of work content accounted for significant decreases in work capacity, including static muscular work, use of muscular strength, lifting and carrying, sudden peak loads, repetitive movements, and simultaneously bent and twisted work postures (Ilmarinen, 1994). This implies the need for ergonomic improvements in the workplace to reduce these risk factors. Aspects of the work environment that contributed to the deterioration of work capacity were dirty and wet workplaces, accident hazards, hot or cold workplaces, and changes in temperature during the workday (Ilmarinen, 1994), implying the need to improve environmental conditions. Work organization risk factors in the Finnish study included role conflicts; unsatisfactory supervision and planning of work; fear of failure and mistake; time pressure; lack of freedom of choice; lack of influence on own work; lack of professional development; and lack of acknowledgment and appreciation (Ilmarinen, 1994; Robertson and Tracy, 1998). Such risk factors are consistent with the job demands-control model of occupational stress and health as described by Karasek and Theorell (1990). Older workers appeared to be more vulnerable to these risk factors than their younger colleagues (Griffiths, 1997:206).

Major factors associated with improving work ability over 11 years of follow-up were improvement in the supervisors’ attitudes, decreased repetitive work movements, and increased vigorous physical exercise during leisure time (Tuomi, Ilmarinen, Martikainen et al., 1997; Tuomi, Ilmarinen, Seitsamo et al., 1997). The major positive components of supervisors’ roles were a positive attitude to the process of aging, team-based cooperation with employees, and taking age-related changes into account in the design and management of work (Tuomi, Ilmarinen, Seitsamo et al., 1997). Predictors of decreasing work ability included lowered recognition and esteem, increased standing at work, poorer workrooms, and decreased vigorous exercise during leisure time (Tuomi, Ilmarinen, Martikainen et al., 1997; Tuomi, Ilmarinen, Seitsamo et al., 1997). Adverse effects “may also be partly due to the rationalization of jobs and to the increase in the total amount of work, required by individual workers, that prevailed generally in the 1990s” (Tuomi, Ilmarinen, Martikainen et al., 1997:70).

High-risk jobs for older workers, now and in the future, are jobs that present exposure to relatively common work risks. These risks have already been characterized, but their prevalence among older workers bears review. The National Health Interview Survey supplement in 1988 provides an estimate of common types of risks and their prevalence by age. The most common risks are biomechanical. (Table A-19 in Appendix A shows biomechanical risks that occur for specific work activities engaged in four or more hours per day.) Among women, 10 percent of those surveyed report repeated strenuous physical activity; almost a quarter report repeated bending, twisting, or reaching; more than one-third report bending or twisting of hands or wrists; but only 3.5 percent report hand operation of vibrating machinery. The prevalence of these biochemical risk factors was higher among men, although the reported difference for bending or twisting of hands or wrists four or more hours per day was similar (40 percent) to that of women. When examined by age of worker the prevalence is somewhat lower for those 45–64 years for each of the biomechanical risk factors; however, even for those 65 and older there is a substantial amount of bending or twisting of hands or wrists of four or more hours (22 percent of employed women and 25 percent of employed men), as well as repeated bending and twisting or reaching (12 percent of employed women and 20 percent of employed men).

The survey also assessed exposures to substances believed to be harmful if breathed or contacted by the skin, and radiation exposure (Table A-20 shows data indicating number and percent distribution of employed adults reporting exposure to substances or radiation at work in 1992). Less than 5 percent of the employed population of women and only 6 percent of employed men reported radiation exposure, with slightly lower percentages among those aged 45 to 64 and even less among those 65 or older. Combining reported harmful exposures, the prevalence is much higher (23 percent for women and 39 percent for men). The prevalence among women is stable for all age groups until 65 or older. Among men, while the exposures decrease for those aged 45 to 64, over one-third still report such exposure. These exposures are almost 20 percent, even among men 65 or older.

In Chapter 2 we identified industries and occupations that are older-worker-intensive. Among those industries the following appear to represent higher risk for both biomechanical and other hazardous exposures: manufacturing, transportation, medical services, mining, utilities, agriculture, and forestry/fishing/trapping. With the exception of mining and forestry/ fishing/trapping, each of these industries is projected to experience at least moderate growth in employment.

Among those occupations identified as older-worker-intensive the following appear to represent higher risk for biomechanical exposures and, in some cases, additional hazardous exposures: administrative support, production/craft/repair, transportation and material moving, farming/forestry/ fishing, private household services, protective services, and services–other. Most of these occupations are projected to experience moderate to high growth in employment.

The ILO estimates that injuries and diseases together cause over 1.2 million fatalities globally per year; workers suffer more than 250 million accidents; and more than 160 million workers fall ill due to workplace hazards and exposures (International Labour Organization, 2004). Anan (1997:59) estimated that the economic burden of such disease and injury amounted to “4 percent of the world’s gross national product; in terms of shattered families and communities, the damage is incalculable.”

The WHO is currently assessing the global burden of disease and death from approximately 20 risk factors, among which are those factors that result in the burden associated with work. Leigh and colleagues provide a summary assessment of the approach being taken (Leigh et al., 1999). The methodology includes consideration of age-specific disease and injury risks, although they have age-adjusted their data to achieve their objectives. In order to arrive at age-adjusted estimates, they have relied on data from countries where conditions are reported by age and sex (Finnish Institute of Occupational Health, 1994; Worksafe Australia, 1995). This approach suggests it may be possible to assess age-specific burdens in the United States if age-specific risk information from other developed countries is used.

Leigh et al. (1999) note that efforts to estimate rates of occupational illness in any jurisdiction are constrained by the fact that most work-related illnesses have multiple potential causes and long latency periods. Work-related events (injury or illness) with rapid onset are easier to identify, but even among these the reporting methods emphasize the most severe and significant events. Other limitations of the available evidence include the general lack of training of health care providers in recognizing occupational illness or disorder and the mix of approaches to data collection used, even within a country with information derived from death records, hospital records, workers’ compensation claims, cancer registry records, workplace records, surveys, and sentinel reports. All of these limitations apply to assessment of occupational illness or disorders and injury burden in the United States.

Within the limitations of available data, Leigh and Schnall (2000) have produced an estimate of the economic burden of occupational illness or disorder and injury in the United States. The study is the first comprehensive estimate that uses national data, though without adequate age-specific data; their report does not consider the problems of older workers. They estimated that there were 13,337,000 occupational injuries in 1992, including 6,371 fatalities. The total estimated cost of those injuries was $132.8 billion. They estimated the occupational illnesses in 1992 to be 1,184,000 and deaths from occupational illness to be 60,290. The total cost of morbidity and mortality from occupational illness was estimated to be $22.8 billion. In 1992, the total loss from occupational injury and illness amounted to approximately 2.5 percent of Gross Domestic Product. Researchers in the United Kingdom and Denmark have made similar estimates of national product lost to occupational illness or disorders and injury.