235 Temporal association between interracial couples and odds of low birth weight infants

Abstract

Women coded as being in interracial relationships have altered odds of low birthweight (LBW). This is likely secondary to societal stressors rather than a biologic basis. Thus, the association should vary over time with sociocultural changes as the proportion of couples coded as interracial has increased. Our aim was to evaluate the association between the odds of LBW in couples coded as interracial and their population incidence over time. Our hypothesis was that the odds of LBW would decrease as the population incidence increased. National Center for Health Statistics Natality data for 1971-2016 was analyzed. LBW was defined as less than 2500 grams. We restricted our analyses to singleton births by White and Black mothers with reported White or Black fathers of the neonate. Logistic regression was used to calculate the odds ratios (OR) of LBW adjusted for maternal education and parental ages and unadjusted. The association between the OR of LWB within a given year and that year’s prevalence of interracial couples was evaluated via meta-regression with random effects. The proportion of couples coded as interracial increased annually from 0.36% in 1971 to 3.86% for White mothers and 0.59% to 8.63% for Black mothers. In each year the OR of LBW was significant. Figures 1 and 2 show each individual year’s OR with a circle proportional to the standard error as well as the metaregression trend line. As the proportion of White mothers with Black partners increased, their OR of LBW declined (1.75 to 1.30, p<0.001). The OR of LBW among Black mothers with White partners, however, did not change (p=0.22). As the annual proportion of White mothers with Black partners increased, their odds of LBW decreased, though was always lower than Black mothers. Black mothers with White partners did not exhibit a similar change. Though causation cannot be established, changes in the proportion of interracial couples over decades is associated with decreasing odds of LBW amongst White women but not Black women.View Large Image Figure ViewerDownload Hi-res image Download (PPT)