Breastfeeding associated with lower CVD risk in high-risk women

A large study has investigated how longer duration of breastfeeding is related to cardiovascular risk among women at high risk of cardiovascular disease (CVD). While it is known that breastfeeding is associated with decreased cardiovascular risk in parous women in the general population, this studied assessed the association among women with prior gestational diabetes or type 2 diabetes.

Cardiovascular disease is the leading cause of morbidity and mortality among people with type 2 diabetes, with the relative CVD risk in women being up to 50% greater than in men. Additionally, the onset of gestational diabetes (GDM) confers a higher risk for CVD, even among women who do not develop type 2 diabetes. 

Breastfeeding provides short- and long-term health benefits to women and their children. In mothers, it is associated with decreased risks of types 2 diabetes, CVD and all-cause mortality. Despite this, rates of exclusive breastfeeding for 6 months postpartum, as recommended by the World Health Organization, are very low.

Researchers analysed questionnaire data supplied by participants in two large cohort studies in the US – the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHS II). They included 15,146 parous women with type 2 diabetes (from NHS and NHS II) and 4537 women with a history of GDM (from NHS II). Breastfeeding history was collected through follow-up questionnaires. 

Incident CVD cases (stroke or coronary heart disease [CHD]) were documented in 1159 women with type 2 diabetes in both cohorts during 188,874 person-years of follow-up. There were 132 incident CVD cases among women with a GDM history during 100,218 person-years of follow-up. 

A longer lifetime duration of breastfeeding was associated with lower CVD risk in women with type 2 diabetes. Compared with women who never breastfed, women cumulatively breastfeeding >18 months had 32% lower CVD and 38% lower CHD in the pooled cohorts. 

Among women with a GDM history, those with a cumulative breastfeeding duration >18 months had a 51% lower risk of incident CVD compared to parous women who never breastfed.

These findings strengthen the evidence of the lifelong benefits of breastfeeding to women at high risk for CVD complications, such as women with type 2 diabetes or GDM, and suggest that breastfeeding might mitigate some of the CVD risk associated with diabetes. The authors conclude that there is a need for greater promotion of breastfeeding as a primary prevention CVD strategy in high-risk women.

The full study findings can be read here.