Beyond the healthy immigrant paradox: decomposing differences in birthweight among immigrants in Spain

Abstract

Background The healthy immigrant paradox refers to the unexpected health advantages of immigrant groups settled in host countries. In this population-based study we analyze immigrant advantages in birthweight decomposing differences between infants born to immigrant mothers from specific origins. Method Using publicly available data from Spanish Vital Statistics for the period 2007–2017, differential birthweights among several groups of immigrants were estimated with an ordinary least squares regression. The Oaxaca–Blinder regression-based decomposition method was then applied to identify the extent to which differences in birthweight between groups corresponded to compositional disparities or to other factors. Results Our analysis of singleton live births to migrant mothers in Spain between 2007 and 2017 (N = 542,137) confirmed the healthy immigrant paradox for certain immigrant populations settled in Spain. Compared with infants born to mothers from high-income countries, the adjusted birthweight was higher for infants born to mothers from non-high- income European countries (33.2 g, 95% CI: 28.3–38.1, P < 0.01), mothers from African countries (52.2 g, 95% CI: 46.9–57.5, P < 0.01), and mothers from Latin American countries (57.4 g, 95% CI: 52.9–61.3, P < 0.01), but lower for infants born to mothers from Asian non-high-income countries (− 31.4 g, 95% CI: − 38.4 to − 24.3, P < 0.01). Decomposition analysis showed that when compared with infants born to mothers from high-income countries, compositional heterogeneity accounts for a substantial proportion of the difference in birthweights. For example, it accounts for 53.5% (95% CI: 24.0–29.7, P < 0.01) of the difference in birthweights for infants born to mothers from non-high-income European countries, 70.9% (95% CI: 60–66.7, P < 0.01) for those born to mothers from African countries, and 38.5% (95% CI: 26.1–29.3, P < 0.01) for those born to mothers from Latin American countries. Conclusions Our results provide strong population-based evidence for the healthy immigrant paradox in birthweight among certain migrant groups in Spain. However, birth outcomes vary significantly depending on the origins of migrant subpopulations, meaning that not all immigrant groups are unexpectedly healthier. A significant portion of the perinatal health advantage of certain immigrant groups is only a by-product of their group composition (by age, parity, marital status, socioeconomic status, and citizenship of mother, age and migratory status of father and type of delivery) and does not necessarily correspond to other medical, environmental, or behavioral factors.

Differences in birth weight between immigrants’ and natives’ children in Europe and Australia: a LifeCycle comparative observational cohort study

“…In France, the largest immigrant group, immigrants from the Middle East and North Africa, showed the strongest advantage in birth weight, mirroring similar results previously found in Belgium 18 39. Birth weights of children with Latin-American and Caribbean mothers were significantly lower in the Dutch cohorts, in contrast to findings in previous work in Spain 12 36…”

“…Previous studies indicate that geographic origins could be associated with children of immigrants’ birth weight. For example, previous work has highlighted higher birth weights for infants born in Spain to African and Latin-American mothers,12 36 while lower mean birth weights were observed for infants born in China to Asian Indian mothers 37. One of the most interesting findings in our study is that children of South Asian mothers showed consistently lower birth weights, in both BiB-UK (where south Asian immigrants represent the largest immigrant group), ABCD-NL and to a lesser extent in the Raine Study-AU.…”

Preterm Birth Risk and Maternal Nativity, Ethnicity, and Race

“…Nativity (where an individual is born) also has important implications for preterm birth as it may serve as a proxy for citizenship, acculturation, preferred language, exposure to interpersonal discrimination, or exposure to structural xenophobia . The immigrant paradox is an epidemiologic observation suggesting that non–US-born racial and ethnic groups have better health outcomes, particularly birth outcomes, than their in-country–born counterparts despite experiencing socioeconomic and health care access–related barriers . However, recent literature has found heterogeneity of perinatal outcomes within immigrant communities by race, ethnicity, and country of origin .…”

Associations of depression with hypertension and citizenship among U.S. adults: A cross-sectional study of the interactions of hypertension and citizenship

“…The U.S. immigrant population has been increasing rapidly and is expected to be a major driver of population growth ( Guadamuz et al, 2020 , Jordan and Gebeloff, 2022 ). New immigrants are known to have lower incidence of chronic health conditions, a phenomenon described as the healthy immigrant paradox ( Bustamante et al, 2021 , Stanek et al, 2020 ). Nonetheless, disparities in healthcare resources, social disadvantages, neighborhood conditions, and low socioeconomic status associated with excess burden of cardiovascular diseases have also been well-documented among immigrants ( Chang, 2019 , de Mestral and Stringhini, 2017 , Hamad et al, 2020 ).…”