Selected acculturation factors and birth defects in the National Birth Defects Prevention Study, 1997–2011

Abstract

Background Acculturation has been examined with respect to various pregnancy adverse outcomes, including birth defects. Given the mixed and limited findings on the association between nativity and birth defects, we sought to further explore parental nativity and years lived in the U.S. across a range of defects. Methods Data from the National Birth Defects Prevention Study were used for this analysis. Infants with one of 46 major isolated birth defects (30 noncardiac/16 cardiac conditions) and infants without birth defects (controls) born during 1997–2011 were included. We examined parental nativity (foreign‐born mothers, fathers, and both parents combined compared to a referent of both U.S.‐born parents) and the number of years lived in the U.S. (≤5/6+ years). Descriptive statistics and logistic regression analyses were performed to estimate crude/adjusted odds ratios and 95% confidence intervals. Results Compared to U.S.‐born mothers, foreign‐born mothers tended to be older (25+ years), of Hispanic or Other race/ethnicity and were less likely to have reported drinking, smoking, illicit drug use, or having taken folic acid. In the adjusted analysis, seven findings among both parents reporting a foreign‐birth were significant, including an increased association with spina bifida, anotia/microtia, and diaphragmatic hernia (aORs range: 1.3–1.7), and a reduced association with craniosynostosis and gastroschisis (aORs = 0.7). A generally protective effect was observed among foreign‐born subjects living in the U.S. ≤5 years. Conclusions We found that nativity was associated with some selected isolated defects, although the direction of effect varied by phenotype and by a number of years residing in the U.S.

Acculturation and selected birth defects among non‐Hispanic Blacks in a population‐based case–control study

“…We found an approximately 30% diminished risk of septal defects among NH Black foreign‐born mothers compared to U.S.‐born. These findings follow previously observed diminished aORs in a recently conducted NBDPS acculturation analysis which found that both mothers and fathers who were foreign‐born (≤5 years in the United States) were also 30% less likely to have infants diagnosed with septal defects (Hoyt et al, ). As with limb deficiencies, a constellation of factors may be present to modify risk for not just septal defects, but a range of CHDs—many of which were found in this analysis to be nonsignificantly diminished in infants born to foreign‐born mothers compared to U.S.‐born (see Table ).…”

“…A constellation of exposures present among U.S.‐born mothers (e.g., higher levels of alcohol, smoking, and prescription/recreational drug use), may place them at higher risk for limb defects than their foreign‐born counterparts. As observed in a previous NBDPS analysis (Hoyt et al, ), foreign‐born mothers were less likely to report: being overweight/obese; having consumed alcohol or high levels of caffeine (300 + mg/day); having smoked or taken illicit drugs (cocaine/methamphetamine) during the periconceptional period; or having been previously diagnosed with high blood pressure. In our examination, foreign‐born NH Black mothers were also more educated (12+ years) compared to U.S.‐born mothers (which was not observed in the other acculturation analysis indicated above).…”

“…As neighborhood deprivation ratings are highly related to poverty scales (Lòpez‐De Fede, Stewart, Hardin, et al, ), it is also interesting to note that across all immigrant groups in the United States, recent immigrants, again defined as those having arrived in the country within the past 5 years, experience higher rates of poverty compared to non‐recent immigrants (arriving 6+ years ago) (Raphael & Smolensky, ). Paradoxically, despite the findings that immigrants are more likely to reside in these “disadvantaged” environments, previous birth defects examinations have found a diminished risk for a range of defects among less acculturated mothers having spent ≤5 years in the United States (Hoyt et al, ; Khodr et al, ; Salemi et al, ; Vu et al, ). The reasons for these findings are likely multifactorial, although investigators in other fields have also observed other paradoxical findings related to immigrant health.…”

“…Two variables were used to examine maternal nativity: (a) whether the mother was born in the United States ( yes/no ); and (b) the number of years foreign‐born mothers resided in the United States (≤5/6+ years) prior to delivery of the child. The 5‐year cut‐point has been utilized in previous NBDPS analyses assessing acculturation (Hoyt et al, ; Khodr et al, ; Ramadhani et al, ). Further, while a variety of methods have been used to examine acculturation, previous analyses examining U.S. acculturation and varying health outcomes (Ai, Appel, & Lee, ; Berrigan et al, ; Schwartz, Unger, Des Rosiers, et al, ) and recent Census data (U.S. Census, 2000), have observed that individuals who have spent ≤5 years in this country represent a population subgroup of “recent” immigrants and these individuals have been noted to differ on many important factors compared to those who have lived in the United States for a greater length of time.…”

“…NBDPS is one of the largest birth defects studies conducted to date in the United States designed to examine various risk factors associated with a range of structural malformations. Building on methodology previously utilized in other NBDPS analyses examining acculturation and a range of defects (Hoyt et al, ; Khodr et al, ; Ramadhani et al, ), primary variables assessed as proxies for acculturation in this analysis included nativity status and number of years spent in the United States with the additional consideration of an array of maternal and infant factors.…”