Abstract
OBJECTIVE: We examined associations between reproductive onset and history of alcohol dependence (AD) in 475 African ancestry (AA) and 2,865 European or other ancestry (EA) female twins. METHOD: Participants were drawn from a U.S. midwestern birth cohort study of like-sex female twin pairs born between 1975 and 1985, ages 21-32 as of last completed assessment. Cox proportional hazards regression models were estimated predicting age at first childbirth from history of AD, separately by race/ethnicity, without and with adjustment for sociodemographic characteristics, body mass index, history of other substance involvement, psychopathology, and family and childhood risks. RESULTS: Among EA twins, AD predicted early childbearing through age 17 and delayed childbearing from age 25 onward; in adjusted models, AD was associated with overall delayed childbearing. Among AA twins, reproductive timing and AD were not significantly related in either unadjusted or adjusted models. CONCLUSIONS: Findings for twins of European ancestry are consistent with well-documented links between early alcohol mis/use and teenage parenting as well as delays in childbearing associated with drinking-related reproductive and relationship difficulties. Extension of analyses to other racial/ethnic groups of sufficient sample size remains important.