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7
Immigrant Health: Selectivity and Acculturation

Guillermina Jasso, Douglas S. Massey, Mark R. Rosenzweig, and James P. Smith


Despite overall improvements in health, there is renewed concern that racial and ethnic disparities in health persist and in some cases may have expanded. Ethnic health disparities are inherently linked to immigration because ethnic identities are traced to the country of origin of an immigrant or his or her ancestors. The average healthiness of the original immigrants, the diversity in health status among immigrants, and the subsequent health trajectories following immigration both over the immigrants’ lifetime and that of their descendants all combine to produce the ethnic health disparities we observe at any point in time. Identifying the determinants of the original health selection of migrants and the forces that shape health paths following immigration is critical to understanding ethnic health differences.

According to the 2000 U.S. Census, there are 32 million foreign-born people now living in this country, constituting about one in nine of the total population. The foreign-born population has been growing rapidly as the numbers of immigrants has been rising in recent decades, reaching rates that rival the number of arrivals at the beginning of the 20th century. Moreover, immigration will be the driving force in accounting for the future growth of the American population. Recent estimates indicate that the American population will increase by 120 million people over the next 50 years, 80 million of who will be the direct or indirect consequence of immigration (see Smith and Edmonston, 1997). These demographic trends suggest that the health status of immigrants and their descendants will play an increasingly central role in shaping health outcomes of the American people. The importance of immigrant health is not limited to an American



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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life 7 Immigrant Health: Selectivity and Acculturation Guillermina Jasso, Douglas S. Massey, Mark R. Rosenzweig, and James P. Smith Despite overall improvements in health, there is renewed concern that racial and ethnic disparities in health persist and in some cases may have expanded. Ethnic health disparities are inherently linked to immigration because ethnic identities are traced to the country of origin of an immigrant or his or her ancestors. The average healthiness of the original immigrants, the diversity in health status among immigrants, and the subsequent health trajectories following immigration both over the immigrants’ lifetime and that of their descendants all combine to produce the ethnic health disparities we observe at any point in time. Identifying the determinants of the original health selection of migrants and the forces that shape health paths following immigration is critical to understanding ethnic health differences. According to the 2000 U.S. Census, there are 32 million foreign-born people now living in this country, constituting about one in nine of the total population. The foreign-born population has been growing rapidly as the numbers of immigrants has been rising in recent decades, reaching rates that rival the number of arrivals at the beginning of the 20th century. Moreover, immigration will be the driving force in accounting for the future growth of the American population. Recent estimates indicate that the American population will increase by 120 million people over the next 50 years, 80 million of who will be the direct or indirect consequence of immigration (see Smith and Edmonston, 1997). These demographic trends suggest that the health status of immigrants and their descendants will play an increasingly central role in shaping health outcomes of the American people. The importance of immigrant health is not limited to an American

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life setting. The United States is only an average country in terms of the fraction of its residents who are foreign born, and increasing rates of international migration make this issue one that transcends borders. Immigrants potentially offer some significant analytical advantages for understanding the origins of health disparities in any population. Most importantly, by definition immigrants have changed regimes, moving from an environment with one set of health risks, behaviors, and constraints into another one that may contain a quite different mix. Given the number of sending countries, the diversity of health regimes from which immigrants flow may be enormous. Because isolating meaningful variation in health environments can be problematic within a domestic-born population, scholars from several disciplines have been eager to use immigrant samples to measure the impact of environmental factors such as diet, health care systems, and environmental risks. But these perceived advantages of immigrant samples do not come without a cost, as immigrant samples also raise difficult analytical issues about the extent of health selectivity and the nature of the appropriate counterfactual. This paper is divided into six sections. The first, section one, provides a simple descriptive comparison of some salient health outcomes of foreign-born and domestic-born Americans. Relying on the existing scientific literature, the section that follows highlights some key findings and the hypotheses these findings generate about the health status of the foreign-born population. Two of the more central questions that have emerged involve the mechanisms shaping health selectivity and the determinants of health trajectories following immigration. With this in mind, the next section outlines some simple theoretical models of health selectivity of immigrants and their subsequent health trajectories following immigration. The following section uses data from the New Immigrant Survey to provide new information on the diversity of health outcomes of new legal immigrants to the United States. New empirical models that estimate the determinants of health selectivity and health trajectories following immigration are presented in the next section. The final section summarizes our views on the principal research and public policy questions about immigrant health that are high priority. It also contains our recommendations about how scientific funding agencies may best assist the research community in answering these questions. HEALTH OF THE NATIVE BORN AND FOREIGN BORN: AN OVERVIEW How do the native born and foreign born compare in terms of their overall health? Two widely used measures of health outcomes are self-reports of general health status based on a five-point scale ranging from

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life excellent to poor and prevalence rates of important chronic conditions. Table 7-1 compares the self-reports of native and foreign-born individuals using the 1996 National Health Interview Survey, and Table 7-2 provides a similar comparison for some common chronic conditions.1 Because immigrants are on average much younger than the native born and health is strongly related to age, the data in these tables are also stratified by age. Using self-reports of general health status in Table 7-1, the foreign-born population in the United States appears to be in slightly worse health than the native born. These differences are concentrated in the higher end of this health scale. For example, conditioned on age, the fraction of foreign born who report themselves in either excellent or very good health is about four or five percentage points lower than that of the native born. The principal exception occurs among those ages 61 to 80; a considerably higher fraction of the foreign born say they are in either fair or poor health. There is growing evidence that residents of different countries use different response thresholds when placing themselves within scales that involve ranking along general well-being criteria, including self-reported health (see Banks, Kapteyn, Smith, and Van Soest, 2004; King, Murray, Solomon, and Tandon, 2003). For this reason, it is useful to also examine other measures of health outcomes that may not be as susceptible to the problem of international differences in response thresholds. The picture is quite different when disease prevalence rates are used instead as the health index. Across all conditions and in every age category listed in Table 7-2, the foreign born have much lower rates of chronic conditions than the native born. For example, for the two most prevalent chronic diseases—arthritis and hypertension—disease prevalence rates are nearly 50 percent higher among the native born. Although these differences TABLE 7-1 Self-Reported Health Status of Native and Foreign-Born Individuals   Age Category   21-30 31-40 41-60 61-80 All Ages Born in United States Excellent or very good 73.9 71.4 60.4 42.7 62.4 Good 21.1 21.4 25.7 32.9 25.1 Fair or poor 5.0 7.2 13.8 24.4 12.5 # of observations 6,750 8,484 12,185 6,642 34,061 Foreign born Excellent or very good 68.7 66.5 56.6 38.9 59.7 Good 25.7 25.9 29.0 30.1 27.5 Fair or poor 5.6 7.7 14.4 31.0 12.8 # of observations 1,747 1,918 2,268 900 6,833 SOURCE: Calculations by authors from 1996 National Health Interview Survey.

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life TABLE 7-2 Prevalence of Chronic Conditions by Nativity Status   Age Category   21-30 31-40 41-60 61-80 All Ages Arthritis U.S. born 2.7 6.7 18.5 42.0 16.9 Foreign born 2.1 2.2 11.4 41.9 11.2 Diabetes U.S. born 0.4 1.5 4.1 11.0 4.1 Foreign born 0.0 1.3 3.5 10.7 3.2 Hypertension U.S. born 3.7 5.9 17.0 36.2 15.3 Foreign born 1.4 4.6 12.9 34.7 10.8 Heart disease U.S. born 3.5 5.1 8.7 19.5 8.9 Foreign born 0.9 2.9 6.2 20.7 6.1 Asthma U.S. born 6.9 5.3 4.6 5.5 5.4 Foreign born 3.7 2.5 3.8 4.8 3.5 Diseases of the lung U.S. born 9.1 7.3 9.9 13.1 9.7 Foreign born 2.4 5.8 6.3 7.4 5.3   SOURCE: Calculations by authors from the 1996 National Health Interview Survey. Note that because questions on specific chronic conditions were given to one-sixth of the sample, the number of observations in this table are approximately one-sixth of those in Table 7-1. are smaller in the other conditions contained in this table (diabetes, heart disease, asthma, and diseases of the lung), in every case lower rates are found in the foreign-born population. When considered together, the data in Tables 7-1 and 7-2 suggest that foreign-born populations may self-report themselves in worse health than the native born do given their objective health circumstances. An alternative view is that self-reports of specific health conditions are underreported in foreign-born populations perhaps due to their less frequent contact with Western medical diagnostics. Cultural, language, and institutional differences across nations may also have a significant impact on what people know and what they report about their illnesses. We return to these issues later in this chapter. Once again, there is some evidence in Table 7-2 of a reversal in ranking among older households. Reported rates of heart disease actually are slightly higher among the oldest foreign-born group listed, and there is a noticeable tendency for differences to converge to near equality among the older populations in all conditions other than diseases of the lung. This apparently more rapid disease progression across age groups among the foreign born in Tables 7-1 and 7-2 is one source of the view that immigrant populations tend to experience more rapid health deterioration over their stay in the United States than is typical of the native-born population.2

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life For several reasons, such a conclusion would be at best premature. As the demographic and labor economics literature has argued and demonstrated repeatedly, patterns obtained from cross-sectional age stratifications may not reveal actual lifecycle realities for anyone (see Smith and Edmonston, 1997). The within-age cell populations in Table 7-2 are members of distinct immigrant cohorts who may differ among other factors in their underlying health. A cross-sectional age pattern inherently cannot separate across-cohort differences from those that represent the pure effects of aging or staying longer in a location. Compounding this problem, there are nontrivial rates of emigration from these immigrant cohorts, and any health selectivity associated with such emigration would add more complexity. Finally, there is no obvious reason why health trajectories of the native-born U.S. population are representative of the health-age profiles that immigrants would have experienced if they had decided not to immigrate. We will return to a fuller discussion of these issues. The immigrants who arrive in any year may also be influenced by forces unique to that year, such as the current state of relative economic conditions in the sending or receiving countries, new legislative changes in the rules governing immigration, or a specific refugee crisis. Consequently, the year immigrants migrate may matter in terms of their initial health outcomes. To illustrate this point, Table 7-3 lists self-reported health status in calendar years 1991 and 1996 among those who last immigrated to the Untied States less than 5 years ago. Health status appears to be lower among the immigrants of the early 1990s compared to those who immigrated during the late 1980s. In every instance in Table 7-3, the fraction that report in fair or poor health is larger in 1996 than in 1991. This variation in health status among immigrants arriving only 5 years apart TABLE 7-3 Self-Reported Health Status by Time Since Immigration and Calendar Year   Age Category   21-30 31-40 41-60 61-80 All Ages 0-5 years in United States in 1991 Excellent or very good 71.9 67.2 52.9 40.6 65.7 Good 23.3 26.9 30.9 34.4 26.2 Fair or poor 4.8 5.9 16.2 25.1 8.2 # of observations 702 364 273 62 1,401 0-5 years in United States in 1996 Excellent or very good 68.3 61.7 43.1 47.6 60.9 Good 24.3 30.3 37.8 14.7 27.9 Fair or poor 7.4 8.1 19.1 37.7 11.2 # of observations 521 256 182 42 1,001 SOURCE: Calculations by authors from 1996 National Health Interview Survey.

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life sends a warning signal that research conclusions drawn from studies of immigrant cohorts from different times in American history may be generalized only with considerable risk. Stratification by age does not provide a direct test of the impact on health of different levels of exposure by immigrants to the U.S. environment. Table 7-4 provides a more direct test by arraying prevalence rates of chronic conditions by length of reported stay in the United States. Because sample sizes are quite thin in any single NHIS year, the data are pooled across all years of the NHIS between 1991 and 1996 inclusive.3 If (controlling for age) all immigrant cohorts were identical at time of entry into the United States, then the patterns observed across time since immigration would inform us about the impact of different durations of exposure to the American health environment. Unlike the age patterns discussed earlier, these data do not speak unambiguously about any effects of differential duration of stay in the United States. For example, among those over age 50, hypertension is most prevalent among those in the 0 to 5 years since immigration group, lung disease is most prevalent among those in the 6- to 10-year group, and arthritis is most common among those with 11 to 15 years of exposure to the United States. In addition to sampling variability, this array is confusing partly because the ceteris paribus of all immigrant cohorts being alike at time of entry is unlikely to be correct. The relatively high rates of hypertension among recent immigrants over age 50 may simply indicate that there is differential health selection by age. The availability of multiple cross-sections from the National Health Interview Surveys (NHIS) allows one to mimic an analysis that has become one of the mainstays in the labor economics literature regarding immigrant assimilation. By appropriately arraying the data by year since immigration and by age, one can in principle track cohorts as they age. This stratification is the basis of Table 7-5, which lists self-reported health status by time TABLE 7-4 Rates of Chronic Conditions of New Immigrants   0-5 6-10 11-15   All 25-44 50+ All 25-44 50+ All 25-44 50+ Hypertension 6.3 2.7 31.8 5.1 3.5 17.0 7.4 3.2 27.6 Diabetes 1.4 0.8 6.1 2.1 1.0 8.2 1.9 0.9 8.0 Cancer 0.2 0.1 1.3 0.1 0.0 1.2 0.2 0.1 0.8 Lung disease 2.1 1.9 3.7 3.2 3.2 5.9 3.2 3.2 3.8 Arthritis 5.3 2.8 23.1 5.3 2.1 24.7 7.0 2.5 26.3 Heart disease 3.7 1.9 18.0 3.7 1.6 11.5 2.6 2.7 14.5 Asthma 1.1 1.3 1.9 2.6 2.7 3.1 2.3 2.2 2.8 NOTE: For each condition, the numbers of observations are about 1,300 to 1,400 in the “All” column for each of the times since immigration, about 800-900 for the 25- to 44-year-old age group and about 200 for the 50+ age group. SOURCE: 1991-1996 NHIS combined files.

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life TABLE 7-5 Self-Reported Health Status by Time Since Immigration   % in Excellent or Very Good % in Fair or Poor Health Health Age Category in 1991 1991 1996 1991 1996 0-5 years since immigration in 1991 21-30 71.9 67.5 4.8 5.9 31-40 67.2 65.7 5.9 10.1 41-60 52.9 46.3 16.2 28.4 6-10 years since immigration in 1991 21-30 67.8 61.1 6.4 7.2 31-40 62.0 69.2 8.3 6.9 41-60 55.2 54.8 10.8 15.7 Born in the United States 21-30 75.4 71.9 4.9 6.5 31-40 72.8 67.0 6.3 9.7 41-60 60.4 54.5 13.5 17.8 NOTE: There are about 55,000 observations in the U.S. born data and roughly 1,300 in the 0-5 and 6-10 years from immigration cells. since immigration and age where both are indexed by their 1991 values. To illustrate, the first entry in the 1991 column refers to those foreign born aged 21 to 30 in 1991 who had migrated to the United States within the previous 5 years. Of that group, 71.9 percent said they were in excellent or very good health. The number adjacent to it under the 1996 column (67.5) represents the self-reported health status of those who were 26 to 35 years old in 1996 and who had last migrated to the United States 6 to 10 years ago. Because both age and time since immigration have been incremented by 5 years, the 1991 and 1996 numbers would refer to the same group of people if the immigrant group was closed. Data are presented separately for those who in 1991 had migrated 0 to 5 years ago and 6 to 10 years ago. The final panel represents those born in the United States. Not surprisingly given that respondents are necessarily getting older, the general tendency for all groups included in this table is that their health deteriorated somewhat between 1991 and 1996. More germane to our topic is the relative profiles of immigrants compared to those born in the United States. Although initial health levels are higher for the native born, there does not appear to be any systematic differential rate of deterioration at the higher health levels between the most recent arrivals (0 to 5 years) and the native born. However, there is some evidence of a greater movement of recent immigrants into the fair or poor category. When we compare the native born to those whose reported 1991 time of arrival was 6 to 10 years ago, if anything immigrant health deterioration may be less than the native born. Table 7-6 performs a similar analysis using prevalence rates of chronic conditions. Two findings stand out from this table. First, by far the most

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life TABLE 7-6 Rates of Chronic Conditions of New Immigrants Foreign Born Age 25-44 30-49 50+ 55+ Years in United States 0-5 6-10 0-5 6-10 Hypertension 2.7 3.9 31.8 18.2 Diabetes 0.8 1.7 6.1 8.8 Cancer 0.1 0.0 1.3 0.7 Lung Disease 1.9 2.6 3.7 8.1 Arthritis 2.8 3.8 23.1 29.5 Heart Disease 1.9 2.2 18.0 14.6 Asthma 1.1 2.9 1.3 4.6 Age 25-44 30-49 50+ 55+ Years in United States 6-10 11-15 6-10 11-15 Hypertension 3.5 4.8 17.0 28.1 Diabetes 1.0 1.2 8.2 11.2 Cancer 0.0 0.7 1.2 0.8 Lung Disease 3.2 3.5 5.9 3.1 Arthritis 2.1 4.6 24.7 29.7 Heart Disease 1.6 2.9 11.5 17.5 Asthma 2.7 2.3 3.1 3.3 U.S. Born: Age 25-44 30-49 50+ 55+ Hypertension 6.4 9.1 31.4 33.9 Diabetes 1.5 2.0 8.8 9.8 Cancer 0.6 0.9 0.8 6.8 Lung disease 8.3 8.5 11.8 12.1 Arthritis 6.3 8.7 37.0 40.6 Heart disease 5.0 6.2 22.8 25.5 Asthma 4.9 4.8 4.7 4.6 NOTE: See Table 7-4 for explanation on number of observations. SOURCE: 1991-1996 NHIS combined files. salient pattern involves health selectivity of immigrants. No matter what duration since immigration is examined, prevalence rates among immigrants are much less than those for the U.S. born. As we will argue, strictly speaking the U.S. native-born population is not the appropriate comparison group to use when evaluating health selection of migrants. Rather, health selection of migrants involves a comparison between the health of migrants and stayers in the sending countries at the time of immigration. This comparison would be extraordinarily difficult given the number of sending countries and the state of health data in most of the sending countries. However, the United States can be used indirectly for this comparison. Because the health of the U.S. native born is so far in excess of those in most

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life migrant sending countries, if migrants to the United States have better health than the U.S. native born, they surely have better health than those who stayed in the sending countries. Using this argument, the extent of this health selectivity is especially strong among younger migrants and for more serious health conditions. For example, prevalence rates for cancer, heart disease, and diseases of the lung are far less for recent migrants than for the U.S. born. Second, if we examine changes in prevalence rates with increasing age (and time since immigration), there is little evidence that the foreign born are doing worse compared to native-born Americans. An important caveat to the analysis contained in Tables 7-5 and 7-6 is that they are examining health changes over short increments in duration of stay. For many illnesses, one would want to examine health changes over much longer durations of stay than 5 years to better capture the impact of changing geographic location. Moreover, the limitations of this analysis implicit in Tables 7-5 and 7-6 are serious when it comes to tracking immigrants. First, immigrant cohorts are not closed, because there is substantial emigration from the original immigrant cohort. For example, up to a third of Mexican immigrants who are in one decennial Census appear to have emigrated by the next. These rates of emigration differ significantly by nationality and across time. Second, the question on time since immigration asked in surveys is subject to considerable ambiguity. The specific question in the NHIS—“In what year did you come to the United States to stay?”—is quite ambiguous. Immigrants typically take many trips to the United States with uncertain intentions about how permanent their residence will be. For example, some may have come for temporary reasons, but subsequently decided to live permanently in the United States. Since they initially did not come to stay, it is unclear how they should answer the NHIS question. MAIN FINDINGS FROM THE LITERATURE There is a vast scientific literature on immigrant health differentials and their determinants that would be impossible to fully summarize here. Instead, we focus our review on that part of the literature that deals centrally with the main issues of the initial health selectivity of immigrants and the subsequent health trajectory following immigration. Epidemiology has a long tradition of using migrant studies to isolate environmental effects on health. Put most simply, the basic notion is that if disease rates change when you move from one place to another, it is indicative of a role for environmental factors. A good example is Marmot’s observation that deaths by motor accidents are high both in France and among French immigrants to England, suggesting that the French bring their “accidents” with them (Marmot, Adelstein, and Bulusu, 1984).

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life A typical epidemiological study examines some health outcome in three populations that presumably differ in a significant way in their environments—people in the host country, the sending country, and migrants. Differences among them then are used to test the impact of some type of “environmental” exposure along a dimension where the groups are believed a priori to differ significantly. Although many differences may exist in their respective environments, the hope is that the design of the study has isolated and measured a small subset of salient differences. These epidemiological studies often examine patterns obtained from specific diseases where knowledge about the origins and progression of disease can be used to help isolate the migrant effect. As a practical matter, these comparisons are often limited to small geographical areas, especially in the host country. As we will see, the substantial heterogeneity in health among immigrants cautions that the use of small geographic areas to capture the representative migrant may be quite perilous. A simple illustrative example of such studies is cited by Kasl and Berkman (1983) and relates to cancer. For example, mortality rates from breast cancer are low among both the Issei (Japanese migrants to the United States) and the Nisei (those born in the United States to Japanese parents), suggesting a genetic interpretation, while colon cancer rates among both the Issei and the Nisei are near the U.S. rates, from which a stronger environmental influence was inferred. Perhaps the most influential of these studies has involved the health of Japanese immigrants to the United States.4 As a typical example of such studies, Marmot and Syme (1976) provide data showing that among men of Japanese ancestry, while all-cause mortality is higher among Japanese men (with cancer as the primary cause of death difference), the risks and occurrence of coronary heart disease (CHD) are lowest among those living in Japan, intermediate among those in Hawaii, and highest among those living in California. Moreover, while attenuated, these differences persisted among nonsmokers and among men with similar levels of cholesterol and/or blood pressure. Marmot hypothesized that the remaining differences may be due to cultural differences between the United States and Japan. Traditional Japanese culture is more characterized by group cohesion and social stability, which may be stress reducing and thus protective in reducing heart disease. Marmot examined health outcomes of Japanese living in and around the San Francisco Bay area, stratified by the degree of adherence to Japanese culture. Among these Japanese men, the more they adhered to the original Japanese culture, both during childhood and during adulthood, the lower the risks of CHD. This association prevails even when dietary preferences are controlled.5 Given its modern migration history with large numbers of migrants from quite diverse cultures (Europe, Asia, and Africa), it is not surprising

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life that Israel has been home to several important studies. The Israel Ischemic Heart Disease Project is a particularly influential research effort. In this study, 10,000 male Israeli government workers aged 40 and over were examined three times during a 5-year period, from 1963 to 1968. These government workers included first generation Israelis from many sending countries. According to the summary provided by Kasl and Berkman (1983), despite the large differences in culture and background across regions of birth, differences in disease rates were surprisingly small. In this case, either large differences in background did not translate into similarly significant health disparities or selection of a specific occupation (government employees) induced too much equality in health outcomes. Finally, in another prospective epidemiological study of 1,001 middle-aged men of Irish ancestry, the relation between dietary information collected approximately 20 years ago and subsequent mortality from coronary heart disease was examined. Following the typical epidemiological protocol, the men were initially enrolled in three cohorts: one of men born and living in Ireland, another of those born in Ireland who had emigrated to Boston, and the third of those born in the Boston area of Irish immigrants. There were no differences in mortality from coronary heart disease among the three cohorts and only weak evidence that diet is related to the development of coronary heart disease. In addition to using migrant samples to test the impact of differential environmental exposure, the second issue that has loomed large in the epidemiological studies concerns the health selection effect. In one of the most comprehensive studies of immigration selection, Marmot, Adelstein, and Bulusu (1984) compared mortality rates of migrants to England from Ireland, Poland, Italy, the Indian subcontinent, and the Caribbean to mortality rates for the sending countries. A summary of their findings is contained in Table 7-7, which lists age-standardized mortality rates compared to those who were born in the United Kingdom (UK). For all countries but Ireland, all-cause mortality rates were much lower among migrants compared to those of residents in the country of origin. While there are no controls for duration of stay, their data are suggestive of quite strong health TABLE 7-7 Standardized Male Mortality Rates for Selected Immigrants to England and Wales (rates relative to United Kingdom)   Migrants Country of Origin Ireland 114 99 Poland 95 107 Italy 77 91 Caribbean 94 119 Indian subcontinent 98 NA SOURCE: Adapted from Marmot et al. (1984, Table 1).

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life transferability. A unique feature of the NIS-P is that it provides information on the earnings of the immigrants in their last job before coming to the United States. More than 77 percent of the immigrants had worked in a foreign country in the 10 years prior to the survey. We converted the earnings in the last job abroad, provided by the immigrants in native currency units, to dollar amounts based on estimates of the country-specific purchasing power of the currencies from the Penn International Comparisons Project, described by Summers and Heston (1991). These conversion factors are explicitly designed to take into account differences in the “cost of living” across countries and to avoid the distortions associated with exchange rate regimes in order to facilitate cross-country comparisons. Table 7-18 contains our estimated models for these two outcomes—Generalized Least Squares (GLS) estimation for the ln of purchasing power parity (PPP)-full time earnings in the sending country and ordered logit estimation for the self-reported health index (scaled from 1 = excellent to 5 = poor). This scale is used to parallel work where mortality is the health outcome. Our basic migration model with worker skill heterogeneity and country skill-price differentials implies that high skill-price countries will send fewer but more skilled and healthier immigrants. How can we measure variation across countries in skill prices? In terms of the observable correlates of skill prices, among workers residing in countries with the same output per worker, those workers residing in countries where workers have higher average skill levels receive lower skill prices, while among workers in countries with the same average worker skill levels, those in countries with higher output per worker will receive higher skill prices. Given immigrant skill heterogeneity and selectivity due to home country skill-price variation, these results imply that immigrants from countries with high output per worker and with low average levels of schooling will have the highest skill levels and best health among immigrants with identical own schooling levels. To measure skill prices in accordance with the model, we used the real (PPP-converted) Gross Domestic Product (GDP) per worker estimates from the Penn World Table, Mark 5.6 supplemented with updated 1995 estimates from the ICP, and estimates of the average schooling levels of the population aged 25 and over in origin countries from Barro and Lee (1993). Average schooling estimates are available for a large but not complete subset of countries for which there are PPP GDP estimates. For those countries for which there are no schooling stock estimates, we constructed a variable indicating that schooling was missing and set the schooling variable to zero. Similarly, home country average health is indexed by female life expectancy, with an indicator variable for the few countries for which we were unable to obtain a value.

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life TABLE 7-18 Determinants of Log of Immigrants’ Home Country Earnings and Health Status Sample Home Country Earners Health Status from Excellent (1) to Poor (5) Variable/Estimation Procedure GLS Ordered Logit Home country characteristic Ln (real GDP/worker) 1.27 (7.71)* –.4329 (1.92) Ln (average schooling in years) –0.91 (2.55) 0.6527 (1.85) Distance to closest U.S. port of entry (miles × 10–4) 0.157 (0.42) 0.429 (0.68) Border country –0.258 (1.22) 1.014 (2.93) U.S. military base –0.0751 (0.31) 0.4748 (1.51) English an official language 0.719 (3.89) –1.138 (3.44) Schooling missing –1.00 (1.76) 1.607 (2.17) Ln life expectancy 0.372 (0.42) –3.197 (2.11) Life expectancy missing 2.088 (0.42) –12.73 (1.91) Characteristic of worker Schooling (years) 0.0441 (2.79) –0.0788 (2.94) Years in the United States 0.1237 (1.43) –0.0221 (0.17) Years in the United States squared –0.0182 (1.86) 0.0051 (0.41) Age 0.0763 (2.17) –0.0367 (0.64) Age squared –0.00061 (1.52) 0.0009 (1.29) Year last worked in home country 0.0464 — (2.42) Female –0.114 (0.90) 0.0620 (0.30) Visa Spouse of U.S. citizen –0.575 (3.13) 0.2551 (0.85) Spouse of U.S. permanent resident alien –0.331 (1.11) 1.728 (4.17) Spouse of employment immigrant –0.393 (2.24) 0.1599 (0.55) Constant (1.87) –9.53   Number of immigrants 342 327 Number of countries 58   Adjusted R2 0.445 0.1065 *Absolute value of t-ratio adjusted for country cluster effects in parentheses in column.

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life We have several measures related to the costs of immigration. The first is whether the immigrant is from a border country to the United States (Mexico or Canada), while the second variable is the distance of the origin country’s capital to the closest major entry city in the United States. The third is an indicator variable taking on the value of one if the country was a host to a U.S. military base in the 5 years preceding the NIS-P survey. Military bases are enclaves of U.S. citizens abroad, many of whom are young and single so that the cost of obtaining entry by marrying a U.S. citizen is lower. The selection framework suggests that countries with military bases, border countries (Mexico and Canada), and countries generally not located at great distances from the United States have lower U.S. immigration barriers or costs and should, given skill prices, be disproportionately sending countries for low-skill and less healthy immigrants. Worker attributes included in these models include own schooling measured in years, number of years in the United States because some of these immigrants obtained their green cards while living in this country, a quadratic in age, sex (an indicator variable set to one for women), and the year last worked in the home country (for the home country earnings equation model only). In addition, three indicator variables for type of visa are included: whether the immigrant obtained a visa as a spouse of a U.S. citizen, a spouse of a permanent resident alien, or a spouse of a principal employment visa immigrant. In column 2 of Table 7-18, we report GLS estimates of ln (national log) home country earnings in a model that includes the country-specific skill price determinants—the log of real GDP per worker and the log of the average schooling of workers—and the individual worker’s individual observable skill attributes. A parallel ordered logit model for self-reported health status is listed in the third column. These specifications also include visa category variables, geographic proximity variables, and years of U.S. residence as determinants of home country earnings to assess how earnings and health selectivity can obscure interpretations of the determinants of the U.S. earnings and health of immigrants. Because the geographic location of a country relative to the United States, the U.S. visa status of an immigrant, and his or her U.S. experience are unlikely to have direct effects on home country earnings or health, the coefficients on these variables mainly reflect selectivity. In conformity to the model, the coefficient on the log of per-worker country output is positive for home country earnings and negative for our health index (with poor health at the top of this index). Similarly, the sign of the coefficient on the measure of average worker skill in the country is negative for ln earnings and positive for health status. Combined, these results indicate that immigrants from countries with high skill prices are, as predicted, positively selected both on their skill and their overall health.

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life Not surprisingly, immigrants from countries where the average health status is better (as measured by average life expectancy) are healthier. These effects are not quantitatively trivial. For example, a doubling of GDP/ worker (holding everything the same), which is equivalent to a doubling in the skill price, would increase the proportion of immigrants in “excellent” health by 20 percent and reduce the proportion in “fair” health by 25 percent. Similarly, a much smaller 10 percent increase in the price of skill increases the proportion of immigrants in “excellent” health by 3 percent and reduces the proportion in fair health by 4 percent. In contrast, there appears to be no relation between country-specific average life expectancy and home country earnings. This may reflect two offsetting forces. First, average life expectancy is correlated with own health, which should increase earnings. But in the formulation in Table 7-18, average life expectancy also is a (negative) proxy for unobserved skill prices, which should reduce earnings. There are several measures of the cost of immigration included in these models. A simple measure of geographic distance does not matter in either equation, perhaps because the distance to the nearest point of entry may not be the most relevant measure given the existence of ethnic enclaves in the United States. In contrast, other things equal, immigrants from the two border countries (Canada and Mexico), where the cost of migration is presumably less, send less skilled and less healthy migrants to the United States. We also estimate poorer health status among migrants from countries with military bases, although this effect is not statistically significant at conventional levels. With respect to effects of personal attributes, our estimates support the conventional finding that own schooling is positively associated with both last home country earnings and with self-assessed health status. Both estimates are statistically significant. The interpretation of the coefficient on U.S. experience is not whether increased time in the United States increases or decreases home country earnings, because home country earnings are measured prior to coming to the United States. Rather, this variable should be interpreted as measuring whether immigrants, of given age, who came to the United States earlier have higher or lower levels of skills. Our results indicate no statistically significant effect of time in the United States on home country earnings. This interpretation is not possible for health status, which is measured instead after arrival in the United States. However, because our results will indicate that health status improves after arrival in the United States, our estimate of a zero net effect of U.S. experience on health in Table 7-18 may indicate that those who come to this country earlier also had worse health on average. Visa status also captures some aspects of immigrant selection. All effects are estimates compared to the left-out group—those who obtained

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life principal employment visas. Although spouses of U.S. citizens and spouses of those who obtained principal employment visas appear to be negatively selected on their labor market skills, there does not seem to be any selectivity on their health status. In contrast, spouses of permanent resident aliens are in significantly poorer health than immigrants on employment visas. In sum, the results in Table 7-18 indicate that there exists systematic variation in the skill and health selectivity of immigrants to the United States that in large part conforms remarkably well with the theoretical predictions outlined earlier. In particular, the country-specific factors that positively select on the skills of new immigrants also appear to positively select on their health status. The results imply that increases in the price of skills in countries outside the United States, a common result of economic development, will lead to a more skilled and healthier immigrant population in the United States. Short-Run Health Trajectories Although it receives almost no mention in the existing literature on health trajectories, one of the biggest changes attributable to immigration is a very large income gain (Jasso et al., 2001). To the extent that income is an important determinant of health status, there is reason to believe that the economic gains of immigrants can result in health improvements. In this section we use new data on immigrants to examine how economic gains from immigration affect health change. Because long-term panel data that follow immigrants from the start of their immigration process are simply not available, estimating models of health change subsequent to immigration is difficult. Once again a data source that offers some potential for examining health change is the New Immigrant Pilot Survey. The random sample of new legal immigrants of the NIS-P was followed up at three subsequent waves. Self-assessed health status, rated from excellent to poor, was reported by all respondents at the 6-month and 12-month interviews, which were actually about 9 months to 1 year apart. In this analysis, we examine changes in self-reported health status ranked as improved, stayed the same, and deteriorated, again using an ordered logit model. We can think of this model as a fixed effects equation. For example, suppose that health is a lagged function of income and other fixed traits (such as schooling, visa, country of origin attributes). Because we have health and income at two points in time, differencing gives the change in health as a function of the lagged change in income. Age is added to the model to capture nonlinearities in age. Our results are reported in Table 7-19. The main explanatory variable is the economic gain from immigration—the difference between the earnings received in the United States and amount earned in the last job in the

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life TABLE 7-19 Ordered Logit of Whether Self-Reported Health Status Improved, Stayed Same, or Deteriorated   Coefficient Z Economic gain 0.0716 3.23 Age –0.0189 1.23 Cut 1 –2.3600   Cut 2 0.3231   sending country. To make earnings in different countries as comparable as possible, as explained earlier, all sending country earnings are adjusted for purchasing power parity. The size and variability of the economic gain from immigration is not trivial. According to the estimates contained in Jasso et al. (2001), the mean economic gain from immigration was about $21,000, around which there was enormous variability. Moreover, the results in Table 7-19 indicate that the income gain associated with immigration positively affects health, so that big gainers are more likely to have subsequently improved health. Recognizing the real possibility of dual causality, one should be cautious about any interpretation dealing with the relation between health and income (Smith, 1999). But given the magnitude of the gains in income due to immigration, it would be difficult to argue that health changes associated with immigration “caused’ these income changes. Most important, the results in Table 7-19 add more reasons for some skepticism about the widely held view that health will decline due to immigration. The impact on one’s health of living in a particular place is probably slow and cumulative, and the results in Table 7-19 only measure short-run changes. However, these economic gains at the time of immigration are unlikely to dissipate over time; in fact, the evidence shows that they will most likely expand over time (Jasso et al., 2001). Thus, even though the model estimated in Table 7-19 only predicts short-run health changes, the persistence of these large economic gains over the long term makes one suspect that on this mechanism at least health improvements might also persist. There is a vast literature spanning several disciplines that argues that income strongly promotes improved health. Why the force of this literature is ignored when the topic shifts to immigration is an interesting question. RECOMMENDATIONS ON RESEARCH PRIORITIES AND FUNDING There are several recommendations for research priorities and funding that are suggested by the findings in this chapter. First, the data have highlighted the enormous heterogeneity that exists within the foreign-born

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life population. This heterogeneity appears in many dimensions, and immigrant health is certainly no exception. The most direct implication of this heterogeneity is that researchers need data with larger sample sizes of immigrants so that they can conduct country-specific analyses. The current, prominent national social science surveys contain immigrant samples as an addendum, roughly in proportion to their role in the overall population. Consequently, sample sizes for even the larger individual immigrant groups are often severely inadequate for meaningful analysis on the topic of immigrant health. If processes of health selection and acculturation vary across immigrant groups, our current data would not be able to detect either for many ethnic groups. Second, it is essential that surveys be designed that capture immigrants at the start of the immigrant process. There are several key advantages to such a design. It allows one to more accurately access the extent of health selectivity at the time of immigration, before the environment in the receiving country has had any significant impact on the immigrant’s health. It also permits an assessment of subsequent health trajectories from the beginning of the immigration process. Currently available immigrant samples are, at best, representative samples of the currently resident foreign-born population—those members of past immigrant cohorts who remained in the United States. Because we know little about the nature of the health selection of those who emigrated, it is impossible to deduce what health trajectories were for the typical immigrant. The New Immigrant Survey is an important step in the direction of obtaining a sample of immigrants at the beginning of a well-defined point—the receipt of a green card—and following all members of that cohort, whether or not they subsequently emigrated. Third, in order to investigate the principal unanswered questions about immigrant health, it is necessary to integrate health, economic, social, and demographic measures within a single survey. Although they are quite useful for documenting health disparities, traditional health surveys such as NHIS or the National Health and Nutrition Environmental Survey are not ideal vehicles for understanding root causes because their measures of the economic, social, and demographic environment are quite limited. Similarly, current economic and demographic surveys are too narrow in the scope and depth of the health information they contain. These new surveys must also incorporate measures of the principal pathways that affect health trajectories. Such measures would include diet, income, and cultural support networks. Finally, it would be quite desirable to supplement observational health measures with physical measurements of health conditions. Fourth, studies of the health outcomes of immigrant children and the children of immigrants also merit high priority on the research agenda. Such research adds an intergenerational component that speaks to possible

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life alternative pathways of health acculturation across generations. Because the outcomes of children are closely tied to the behaviors and constraints faced by their immigrant parents, it is important to include children in the same surveys as their parents. These children are the eventual future legacy of immigration so understanding the determinants of their health addresses the issue of the long-term impact of immigration on the health of the American population. Fifth, an important insight from the epidemiology literature is that investigations of specific diseases can help elucidate the pathways through which immigration affects health. For example, models that emphasize the impact of psychosocial stress associated with the process of immigration often see the main manifestations of this stress showing up later in diseases of the heart. Similarly, exposures to certain environmental or behavioral risks such as smoking may lead to increased risks of cancers or other diseases of the lung. Consequently, it is important to be able to track specific disease progressions of immigrants that can then be contrasted to those that characterize their native-born counterparts. Sixth, the subject of immigrant health argues for the value of comparable international comparison studies. One of the arguments in favor of studies of immigrant health is that the diversity of health environments represented by the many sending countries offers an important analytical tool for studying effects of geographical environment on health. A similar agreement can be made about the receiving countries. The United States is not a unique country in terms of its position as an immigrant-receiving nation, and the considerable diversity among receiving countries will also provide much useful information. Conclusions In this chapter, we have explored some salient issues concerning immigrant health. Ethnic health disparities are inherently linked to immigration because ethnic identities often are traced to the country of origin of one’s immigrant ancestors. Two of the central questions that have dominated the medical and social science literature on immigrant health are the central focus of this chapter. These issues involve the magnitude and mechanisms shaping health selectivity and the determinants of health trajectories following immigration. Health selection—the propensity of immigrants to be much healthier than a representative person in the sending country—is a quantitatively important phenomenon that is fundamental to understanding the most basic patterns that emerge about immigrant health. Immigrants are quite healthy and are very positively selected on this trait. However, great diversity exists among immigrants in the extent of health selection. In addition, the nature of health selection of immigrants appears

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life to be fundamentally different among older immigrants, who have largely passed their prime working years. As part of this chapter, we also developed a theoretical model that attempts to explain the diversity in health selection among immigrants. One of the consequences of this strong health selection effect is that it makes current evidence of health trajectories following immigration very problematic. For example, the general theme in the literature appears to be that immigration to the United States may have deleterious health consequences. However, this pattern is also easily explained simply by positive health selection on currently observed health traits and outcomes and then the subsequent necessary regression toward the mean. Research on health trajectories following immigration also frequently suffers from some confusion on what the appropriate comparison group should be. The issue is what an immigrant health profile is following immigration compared to what it would have been if he or she did not migrate. Comparisons that have dominated the existing literature that rely principally on how immigrants fare relative to native-born populations do not directly speak to the issue of the effects of immigration on lifetime health profiles. ACKNOWLEDGMENT Paper prepared for National Academy of Sciences Conference on Racial and Ethnic Disparities in Health. This research was supported by grants from the National Institutes of Health. ENDNOTES 1.   The National Health Interview Survey (NHIS) is conducted annually by the National Center for Health Statistics, Centers for Disease Control and Prevention. The NHIS annually administers interviews to a nationally representative sample of about 43,000 households, including about 106,000 persons. From each family in the NHIS, one sample adult and one sample child, if any, are randomly selected, and more detailed information on each is collected. To economize on interview length while asking detailed and comprehensive questions about specific conditions, until recent survey waves individuals were randomly assigned into six groups to ask questions about specific chronic conditions. 2.   These data are consistent with the classic study by Kitagawa and Hauser (1973), which showed that mortality rates of the foreign born during middle age (35 to 64) were lower than those of the native born, but the reverse was true at older ages. 3.   There are only 143 people in the NHIS asked a specific question about diabetes who had migrated within the previous 5 years. 4.   This study is referred to as the Japanese-American Coronary Heart Disease Study. It included 11,900 men ages 45 to 69 in Hiroshima, Nagasaki, Honolulu, and the San Francisco Bay area.

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Critical Perspectives on Racial and Ethnic Differences in Health in Late Life 5.   This does not mean that diet was not important. According to Marmot and Syme (1976), the mean percentage of fat in the diet ranged from 15 percent in Japan to 37.6 percent in California Japanese. 6.   One useful addition would be to model return migration where one particular dimension would concern migration back to the source country following retirement. The labor market conditions emphasized in the text would no longer receive great weight. While quality of medical care might encourage staying in the United States, the lower cost of living would make return migration more likely. Another extension would concern the initial and subsequent health of minor children who accompany their parents in the migration process. The extent of health selection is probably muted for minor children because the correlation in health of migrant parents and migrant children is far from perfect. In addition, there is some concern that the social environment in the United States for some immigrants may be quite risky, especially for adolescents. These concerns often center on drugs, alcohol, and gang behavior. Although the health of the children of migrants is an important topic, it is not our main concern here. 7.   These conclusions would not change if we control for age. 8.   For example, a person who has been generally sickly throughout their lives may require more medical care. If we do not control for this persistent unhealthiness, a regression of current health on medical services will understate the efficacy of medical care. 9.   This production function, which summarizes the transformation of these inputs into health outputs, is typically governed by biological considerations. 10.   For good examples, see National Research Council (2002). 11.   Response rate at baseline was 62 percent and attrition by the 12-month interview was 5 percent. See Jasso et al. (2000) for details. 12.   This qualified statement is necessary as having some physician contact may be a quite inadequate control. Immigrants and the native born may differ as well in the many other dimensions of contact, such as the quality of the consultation and the type and depth of the information exchanged. In addition, seeing a physician about one issue (e.g., an eye problem) may not make one aware of others (e.g., hypertension). In addition, doctors may act in a passive role, only treating the specific complaints that individuals report. These types of physician behavior may also vary across countries. REFERENCES Banks, J., Kapteyn, A., Smith, J.P., and Van Soest, A. (2004, February). International comparisons of work and disability. Paper presented at NBER conference on disability, Charleston, South Carolina. Barro, R., and Lee, J.W. (1994). International comparisons of educational attainment. Journal of Monetary Economics, 32(December), 363-394. Centers for Disease Control and Prevention. (2001). Health: United States: 2001 with urban and rural health chartbook. Hyattsville, MD: National Center for Health Statistics. Grossman, M. (1972). The demand for health: A theoretical and empirical investigation. New York: National Bureau of Economic Research. Jasso, G., Massey, D., Rosenzweig, M., and Smith, J.P. (2000). The new immigrant pilot survey (NIS): Overview and findings about U.S. immigrants at admission . Demography, 37(1), 127-138. Jasso, G., Rosenzweig, M., and Smith, J.P. (2001). The earnings of U.S. immigrants: World skill prices, skill transferability and selectivity. Unpublished manuscript. Kasl, S.V., and Berkman, L. (1983). Health consequences of the experiences of migration. Annual Review of Public Health, 4, 69-90.

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