Association Between Breastfeeding and Long-Term Risk of Cardiovascular Disease

OBJECTIVE: To estimate whether breastfeeding is associated with the estimated risk of long-term atherosclerotic cardiovascular disease (ASCVD) and whether this association varies with prior gestational diabetes mellitus (GDM). METHODS: We conducted a secondary analysis from the prospective HAPO (Hyperglycemia and Adverse Pregnancy Outcome) Follow-Up Study. The exposure was any breastfeeding (yes or no). The primary outcomes, measured 10–14 years after delivery with the Framingham Risk Score, were estimated ASCVD risk (composite of fatal and nonfatal coronary heart disease and stroke) over the subsequent 10- and 30-year time periods. Multivariable linear regression models were used and adjusted for baseline pregnancy covariates: field center, age, body mass index (BMI), height, smoking and alcohol use, parity, and time from delivery to ASCVD risk assessment. Secondarily, we examined whether the association between breastfeeding and ASCVD varied by GDM status (effect modification). RESULTS: Of 4,540 individuals, the median age was 30.6 years at baseline. More than three-fourths (79.7%) reported breastfeeding, which did not vary by GDM status (79.5% vs 81.0%). At 10–14 years after delivery (median 11.6 years), individuals who breastfed had a lower estimated risk of ASCVD over the subsequent 10 years (2.3% vs 2.5%, adjusted β −0.13, 95% CI, −0.25 to −0.02) and 30 years (6.2% vs 6.9%, adjusted β −0.36, 95% CI, −0.66 and −0.05). The association between breastfeeding and estimated ASCVD risk varied significantly by GDM status: The protective effect of breastfeeding was greater for individuals with GDM for estimated 10-year ASCVD risk (GDM: adjusted β −0.52, 95% CI, −0.98 and −0.05; no GDM: adjusted β −0.09, 95% CI, −0.20 and −0.02; interaction P =.004) and 30-year ASCVD risk (GDM: adjusted β −1.33, 95% CI, −2.53 and −0.14; no GDM: adjusted β −0.25, 95% CI, −0.54 and 0.03; interaction P =.003). CONCLUSION: Breastfeeding, particularly after an individual had GDM, was associated with a lower estimated risk of long-term ASCVD. These findings indicate the potential benefit of breastfeeding for long-term cardiovascular health, especially among those with GDM.