Breastfeedings and cardiovascular disease hospitalisation and mortality in mothers from a large Australian cohort study

Abstract

Background There is growing evidence that breastfeeding has short- and long-term maternal cardiovascular health benefits. However, few studies have investigated the longitudinal association between breastfeeding and maternal cardiovascular disease (CVD) outcomes. This study aimed to examine the association between breastfeeding and (1) CVD hospitalisation, and (2) CVD mortality in a large Australian cohort. Methods Baseline questionnaire data (2006–2008) from a sample of 100,864 parous women aged ≥ 45 years from New South Wales, Australia, were linked to hospitalisation and death data until June 2014 and December 2013, respectively. CVD hospitalisation was based on the first CVD-related hospitalisation since baseline in women without self-reported medically diagnosed CVD at baseline or without prior CVD hospitalisation in the six years prior to study entry. Self-reported lifetime breastfeeding duration was categorised as: never breastfed, > 0–6 months, > 6–12 months, > 12–24 months and ≥ 24 months. Ever versus never breastfeeding was also compared. Cox proportional hazard models were used to explore the association between breastfeeding and CVD outcomes. Covariates included sociodemographic characteristics, lifestyle risk factors, and medical and reproductive history. Results There were 3,428 (3.4%) first CVD-related hospital admissions and 418 (0.4%) deaths during a mean follow-up time of 6.1 years for CVD hospitalisation, and 5.7 years for CVD mortality. In the unadjusted and fully-adjusted models, ever breastfeeding was associated with lower risks of CVD hospitalisation and CVD mortality compared to never breastfeeding (all P 0.1). Conclusions Ever breastfeeding, and to some extent lifetime breastfeeding duration, are associated with lower maternal risk of CVD hospitalisation and mortality in this large cohort of middle-aged and older Australian women. Breastfeeding may offer long-term maternal cardiovascular health benefits.