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Breastfeeding may help protect against stroke

Post-menopausal women have lower risk of stroke if they breastfed

Ingrid Torjesen

Wednesday, 22 August 2018

Post-menopausal women have a lower risk of stroke if they breastfed at least one child, a study* published in the Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association, has found.

The study also suggested that the impact of breastfeeding on stroke risk also varied according to ethnicity, with black and Hispanic women benefitting most from having breastfed.

Researchers analysed data on 80,191 participants in the Women's Health Initiative observational study, a large ongoing national study that has tracked the medical events and health habits of postmenopausal women who were recruited between 1993 and 1998.

All women in this analysis had delivered one or more children and 58% reported ever having breastfed: 51% breastfed for 1-6 months, 22% for 7-12 months and 27% for 13 or more months. At the time of recruitment, the average age was 63.7 years and the follow-up period was 12.6 years.

After adjusting for non-modifiable stroke risk factors (such as age and family history), researchers found stroke risk among women who breastfed their babies was on average 23% lower, and longer breastfeeding was associated with a greater reduction in risk.

Breastfeeding benefitted black women most, as those that did saw their stroke risk almost halve (48% lower risk). Stroke risk fell by a third (32%) in Hispanic women who had breastfed, and by a fifth (21%) in white women who had done so.

Lead author of the study, Lisette Jacobson, assistant professor in the department of preventive medicine and public health at the University of Kansas School of Medicine, Wichita, said: "Some studies have reported that breastfeeding may reduce the rates of breast cancer, ovarian cancer and risk of developing type 2 diabetes in mothers. Recent findings point to the benefits of breastfeeding on heart disease and other specific cardiovascular risk factors."

She added: "Our study did not address whether racial/ethnic differences in breastfeeding contribute to disparities in stroke risk. Additional research should consider the degree to which breastfeeding might alter racial/ethnic differences in stroke risk."

Jacobson said women should breastfeed for at least six months to receive the optimal benefits for themselves and their infant.

The World Health Organization recommend exclusive breastfeeding for six months, with continuation of breast feeding for one year or longer.

As the study was observational, it couldn't establish a cause-and-effect relationship between breastfeeding and lower stroke risk, the researchers said, meaning that it is possible some other characteristic that distinguishes between women who breastfeed and those who don't is the factor changing the stroke risk.

The study was also limited by the relatively small number of strokes that occurred during the follow-up period (just 3.4% of the women experienced a stroke during the study period and 1.6% reported having had a stroke prior to the study) and by the Women's Health Initiative's exclusion of women who had already had severe strokes at the time of recruitment.

*Jacobson LT, Hade EM, Collins TC, et al. Breastfeeding History and Risk of Stroke Among Parous Postmenopausal Women in the Women's Health Initiative. Journal of the American Heart Association. 2018;7:e008739

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