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

Background: There are noted birth defects prevalence differences between race/ethnicity groups. For instance, non-Hispanic (NH) Black mothers are more likely to have an infant with encephalocele, although less likely to have an infant with anotia/microtia compared to NH Whites. When stratifying by nativity and years lived within the United States, additional variations become apparent.

Methods: Data from the National Birth Defects Prevention Study were used to calculate descriptive statistics and estimate crude/adjusted odds ratios (aORs) and 95% confidence intervals (95%CIs) among NH Blacks with one of 30 major defects and non-malformed controls. Total case/controls were as follows: U.S.- (2,773/1101); Foreign- (343/151); African-born (161/64). Study participants were also examined by number of years lived in the U.S. (≤5 vs. 6+ years).

Results: Compared to U.S.-born, foreign-born NH Black controls tended to be older, had more years of education, and were more likely to have a higher household income. They also had fewer previous livebirths and were less likely to be obese. In the adjusted analyses, two defect groups were significantly attenuated: limb deficiencies, aORs/95%CIs = (0.44 [0.20-0.97]) and septal defects (0.69 [0.48-0.99]). After stratifying by years lived in the United States, the risk for hydrocephaly (2.43 [1.03-5.74]) became apparent among those having lived 6+ years in the United States. When restricting to African-born mothers, none of the findings were statistically significant.

Conclusions: Foreign-born NH Blacks were at a reduced risk for a few selected defects. Results were consistent after restricting to African-born mothers and did not change considerably when stratifying by years lived in the United States.