Fionnuala M. McAuliffe

Objective The aim of the present study was to investigate associations between lifetime breastfeeding behaviors and cardiovascular risk in later reproductive years. Method This was a prospective 10‐year longitudinal cohort study of 168 parous women. Health, lifestyle and infant feeding questionnaires, blood samples, anthropometry and body composition were collected. Cardiovascular risk was estimated using QRISK®3 and hierarchical multiple linear regression analysis performed. Results Mean age was 42.4 years (SD 3.8; range 31–50) and 98.7% ( n = 156/158) were premenopausal. Ever breastfeeding rates were 72.6% ( n = 122/168) and 37.5% ( n = 63/168) lifetime ≥12 months breastfeeding duration. Median durations were 5.5 weeks for exclusive breastfeeding (IQR 35.8; range 0–190) and 30.5 weeks for any breastfeeding (IQR 84.0; range 0–488). Breastfeeding duration was not associated with QRISK®3 scores in adjusted models. Lower glycoprotein acetyls were associated with ever breastfeeding ( P = 0.03), and lifetime breastfeeding ≥12 months ( P = 0.001). Lifetime breastfeeding ≥12 months and longer exclusive breastfeeding were associated with lower fat mass index ( P = 0.03, P = 0.01), tissue percentage fat ( P = 0.02, P = 0.009) and visceral adipose tissue volume ( P = 0.04, P = 0.025) after correcting for confounders including body mass index. Conclusion Longer breastfeeding is associated with favorable body composition and lower glycoprotein acetyls, a novel inflammatory biomarker associated with cardiometabolic risk. Breastfeeding is a low‐cost, health promoting behavior for women and infants. Pregnant women, especially those at higher risk of cardiovascular disease, should be counseled about the potential benefits of exclusive and longer breastfeeding duration.