UCSF

Objective: It has been reported that mothers who do not breastfeed are at an increased risk of T2DM, metabolic syndrome, and CVD. We hypothesize that lactation may influence cardio-metabolic risk by altering maternal body composition. We examined the extent to which lactation was associated with regional and total adiposity in a sample of US women 15 years after their last birth. Study Design : Cross-sectional analysis of data provided by 1,268 women aged 45-58 who enrolled in the Study of Women’s Health Across the Nation (1996 -1997). Adiposity was assessed using dual-energy X-ray absorptiometry. History of lactation was self-reported and categorized into three groups: mothers who breastfed for ≥3 months after every birth, those who discontinued lactation within 3 months of some births, and those who never breastfed. Results: Compared with mothers who breastfed after every birth for at least 3 months, mothers who never breastfed had 0.87 kg greater trunk fat mass (FM), 1.3% greater % trunk FM, 1.3% lower % leg FM, and 0.075 greater trunk to leg FM ratio after adjustment for age, parity, height, years since last birth, race/ethnicity, socioeconomic, lifestyle, psychological, and family history variables, maximum gestational weight gain, and menopausal status. After additional adjustment for current BMI, women who never breastfed had 0.40 kg greater trunk FM and 0.053 greater trunk to leg FM ratio than mothers who breastfed every child for ≥3 months. Similarly, mothers who discontinued lactation within 3 months of some births had 0.28 kg greater trunk FM and 0.87% lower % leg FM than mothers who consistently breastfed. Conclusion : Women who did not breastfeed for at least 3 months after every birth exhibit less favorable body fat distributions 15 years postpartum. These results provide a potential physiologic basis for prior findings that women who do not breastfeed their children face increased risk of diabetes, the metabolic syndrome, and cardiovascular disease. Given existing disparities in rates of lactation, obesity and CVD, these findings have great clinical relevance and suggest the need for targeted lactation support for women at risk of cardiovascular disease.