摘要：Objectives. We examined whether acculturation and immigrant generation, a marker for assimilation, are associated with diabetes risk in an aging Mexican-origin population. Methods. We analyzed data on 1789 adults aged 60 to 101 years from the Sacramento Area Latino Study on Aging. We ascertained type 2 diabetes on the basis of diabetic medication use, self-report of physician diagnosis, or a fasting glucose of 126 milligrams/deciliter or greater. Logistic regression modeled prevalent diabetes. Results. Adjusting for age and gender, we observed significant but divergent associations between immigrant generation, acculturation, and diabetes risk. Relative to first-generation adults, second-generation adults had an odds ratio (OR) of 1.8 (95% confidence interval [CI] = 1.4, 2.4) and third-generation adults had an OR of 2.1 (95% CI = 1.4, 3.1) of having diabetes. Greater US acculturation, however, was associated with a slightly decreased diabetes rate. In the full model adjusting for socioeconomic and lifestyle factors, the association between generation (but not acculturation) and diabetes remained significant. Conclusions. Our study lends support to the previously contested notion that assimilation is associated with an increased diabetes risk in Mexican immigrants. Researchers should examine the presence of a causal link between assimilation and health more closely. Diabetes is increasing in the United States 1 and in countries that contribute the largest number of immigrants to the United States. 2–4 These immigrant populations, who originate from countries where diabetes is prevalent, provide a unique opportunity to study the development of diabetes. They are a “high event” population because of possible genetic predisposition, 5–8 and they experience rapid change in exposures; thus, they provide an efficient way to study the impact of environmental change on the progression of diabetes. Immigrants are a large and dynamic segment of the US population. Between 1990 and 2000, the foreign-born population in the United States increased 57.0%, from 19.8 million to 31.1 million, compared with an increase of 9.3% for the native population. 9 It has been projected that 87.0% of the population growth between 2005 and 2050 will be driven by immigrants and their children. 10 In California, for example, Latino children, many of whom are immigrants or children of immigrants, for the first time make up the majority of the population younger than 18 years. 11 Mexico is the largest contributor of immigrants to the United States 12 and has recently experienced rapid increases in both obesity and diabetes. 13–15 From 1994 to 2006, the national prevalence of diabetes in Mexico more than doubled, going from 6.7% to 14.4%. 13 This pattern is common in developing countries undergoing rapid urbanization. Social and economic change of rapid urbanization has led to more sedentary lifestyles and greater consumption of processed foods and calories, a process that has been labeled the “nutrition transition.” 16,17 In the United States it is well known that relative to non-Latino Whites, Latinos—those of Mexican origin in particular—bear a much larger burden of diabetes. 18–22 Because Latino immigrants constitute the largest proportion of immigrants to the United States by far, there has been interest in understanding whether acculturation to US lifestyles contributes to their heightened diabetes risk. The evidence on whether the risk of type 2 diabetes in Latino immigrant populations increases with greater time in the United States or acculturation, however, is mixed. 23–27 It is well documented that immigrants arrive with a health advantage despite an adverse social and economic profile, possibly reflecting migration selectivity 28–33 or the protective culture of immigrants, which encourages healthy behaviors and strong social support systems. 34,35 Over time, however, immigrants and subsequent generations lose at least some of this initial health advantage. 36,37 It is unknown whether diabetes contributes to the decline in the initial health advantage (sometimes called “unhealthy assimilation”). 37 Furthermore, diabetes presents a unique case, as it is 1 of the few conditions for which evidence suggests that, relative to non-Latino Whites, Latinos carry a considerably higher risk and consequently are at a greater health disadvantage; it has been suggested that both genetics and environment contribute to this heightened risk. 6,32,38,39 Although the Mexican national rate of diabetes is almost one and a half times higher than is the US rate, 2,40 it is not clear whether the US setting slows or accelerates the development of diabetes. On the one hand, Mexican immigrants are moving from a country with high rates of diabetes to one with lower rates. But diabetes growth worldwide has also been attributed to global secular shifts in lifestyles and diet that result from upward social mobility and rapid urbanization. 41–43 Because Mexican immigrants to the United States are moving to a more affluent society, it would also be reasonable to postulate that their diabetes risk will be heightened with longer time or after several generations of living in the United States. 44 Some studies have examined whether diabetes increases with longer US residence in middle-aged populations 24,26 ; however, we are the first, to our knowledge, to focus on an aging Mexican-origin population, aged 60 years and older. We also examined whether there is significant heterogeneity in diabetes risk across different generations. Consistent with the unhealthy assimilation perspective, 37 we examined whether diabetes risk increases from the immigrant generation to US-born second and third generations, using data from the Sacramento Area Latino Study on Aging (SALSA).
