Acculturation, socioeconomic status, and body weight trajectory among adults of immigrant origins in the U.S

Socioeconomic status (SES) and acculturation are important predictors of health in immigrant populations. However, the immigrant health literature largely overlooks the relationship between SES and acculturation. Using data on immigrants with developing country origins in the National Longitudinal Survey of Youth 1985-2010, the study examines the joint effects of SES and acculturation on Body Mass Index (BMI) and its trajectory from age of early 20s till late 50s. It asks 1) How does adult SES and acculturation influence immigrant weight over time? 2) How does childhood SES and acculturation influence immigrant weight over time?) 3) Does adult SES mediate the influences of childhood SES on immigrant weight and does the mediation process vary by acculturation? 4) How does social mobility and acculturation influence immigrant weight over time?;Adult SES is measured by education and family income. Childhood SES is measured by an index that combines the parental education and the occupation of the primary adults in household during the respondent's childhood. Social mobility is measured by comparing the occupation of primary adults in the respondent's childhood and the respondent's or spouse's occupation at age 25. Acculturation is assessed by two proxy measures, including immigrant generation and language spoken in childhood. The results of linear mixed effects models indicate a non-significant relationship between adult SES and BMI for the first and second generations. Among the first generation immigrants, high education is related to higher BMI for those speaking only English in childhood, but to lower BMI for those speaking other languages. Among the first generation immigrants, the BMI difference attributable to education decreases, increases, and finally decreases over age between 20s and the age of 60. No differences in the relationships between adult SES and BMI/BMI changes are found across language spoken for the second generation. For the third and plus generation speaking only English, the adult SES-BMI relationship is negative when adult SES is measured by education, and positive when it is measured by income. No relationship between adult SES and BMI is found for the third and plus generation speaking other languages.;The results indicate a negative relationship between childhood SES and BMI for immigrants with different generation status and English proficiency. Lower BMI is found among the second generation than the third and plus generation; and the relationship is stronger among those with high SES in childhood. The childhood SES-BMI relationship is similar for the first and third and plus generations, even though a lower average BMI is found among the first generation immigrants. For the first and third and plus generations, the negative childhood SES-BMI relationship is stronger among those speaking non-English languages, than among their counterparts speaking only English in childhood; but for the second generation, the childhood SES-BMI relationship is stronger among those speaking only English in childhood.;The BMI difference attributable to childhood SES decreases over age for the second and third and plus generations, and it remains steady for the first generation immigrants. Among the first and second generations, lower BMI attributed to speaking only English in childhood remains from age 20s to age 50. For the third and plus generation, BMI difference attributed to childhood SES is small and shows a pattern of initial decrease, subsequent stability, and final increase for those speaking only English; it follows an increasing and then decreasing pattern over age for their counterparts speaking languages other than English. The third and plus generation speaking only English exhibit higher BMI than their counterparts speaking other languages among those with high childhood SES; this relationship is evident from age 20 until age 58.;Neither education nor income mediates the effects of childhood SES on BMI for the second generation. For the first and third and plus generations, adult education mediates the effects of childhood SES on BMI, but the mediation only explains a limited part of the relationship. For the first generation immigrants, upward mobility is related to lower BMI than stable low status but does not differ from stable high status. For the second generation, upward mobility is related to higher BMI than stable high and low statuses. For the third and plus generation speaking non-English languages in childhood, upward mobility is related to lower BMI than stable high and low statues.;The results provide evidence that SES and acculturation jointly affect immigrant BMI; while indicating complicated relationships among SES, acculturation, and BMI. First, the study partially supports the flat adult SES-BMI relationship for newly arrived immigrants. Second, it suggests adult education is a more sensitive SES measure than family income in analyzing health outcomes, such as BMI. Third, the study supports a critical effect of early life experience in adult life which mostly is not through its projection into SES in adulthood. This effect is evident regardless of acculturation level. Fourth, decreasing, not increasing, health disparities attributed to SES are consistent with an "age-as-leveler" theory. Fifth, the study depicts distinct relationships between SES, English proficiency, and BMI for different generations of immigrants. This finding suggests different roles language plays across stages of acculturation. Sixth, the study indicates a "healthy immigrant paradox" among highly acculturated immigrants. The study provides new starting points for future research in the field of immigrant studies.