Abstract MP57: Lactation Duration is Associated With Lower Visceral and Pericardial Fat Volumes in Parous Women: 25-year Follow-up in the Cardia Study

Abstract

Introduction: Lactation has been associated with a lower risk of incident type 2 diabetes mellitus and cardiovascular disease (CVD) in women. However, the underlying mechanisms for these associations are not well understood. The longitudinal association between lactation and maternal fat volume has rarely been investigated. Hypothesis: We tested the hypothesis that lactation duration is inversely associated with maternal visceral and pericardial fat volumes. Methods: Data were obtained from 910 women enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study (1985-86) without diabetes prior to pregnancy who had ≥1 birth during 25 years of follow-up. Cumulative lactation duration across all births since baseline was calculated from self-reports collected at each exam. Volumes of visceral and pericardial adipose tissue were measured from computed tomographic scans at the Year 25 exam in 2010-2011. Methods: At baseline, the average age of women (48% black, 52% white) was 24 years (range: 18-30 years). During 25 years of follow-up, 76% of women reported lactation duration of ≥ 1 month. In adjusted linear regression models, lactation duration was inversely associated with visceral fat (p=0.021) and pericardial fat (p=0.001) volumes (Table). There was a significant interaction between race and lactation on visceral (p=0.035) and pericardial fat (p=0.027) volumes (Table). Formal mediation analysis showed a significant indirect effect of lactation duration on visceral (p=0.001) and pericardial fat (p=0.002) volumes through body weight change between the first postbaseline birth and the end of follow-up. Changes in body weight mediated 29.4% and 26.0% of the association between lactation duration and visceral and pericardial fat volumes. Conclusions: In this prospective study, the associations of longer lactation duration with lower visceral and pericardial fat volumes were partially mediated by body weight changes.