Abstract

Background: Being breastfed is associated with lower cardiovascular risk factors but, to date, no studies have demonstrated a protective effect on cardiovascular disease (CVD). This study aims to address the limitations of previous studies, specifically insufficient statistical power and residual confounding, to determine if such association exists. Methods: This is a population-based retrospective cohort study of 320 249 men and women aged 40–69 years. Breastfeeding status was self-reported. CVD and myocardial infarction (MI) events and deaths based via linkage to hospitalization and death records. Results: Overall, 28 469 (8.4%) participants experienced a CVD event and 5174 (1.6%) experienced an MI. Following adjustment for sociodemographic, lifestyle and early life confounders, breastfeeding was associated with a reduced risk of CVD events (HR 0.97, 95% CI 0.94–1.00, P = 0.041), CVD deaths (HR 0.91, 95% CI 0.84–0.98, P = 0.017), MI events (HR 0.93, 95% CI 0.87–0.99, P = 0.033) and MI deaths (HR 0.81, 95% CI 0.67–0.98, P = 0.026). Conclusions: Child health benefits of breastfeeding are well established. However, the benefits of breastfeeding may extend into later life reinforcing the need to encourage and support breastfeeding.