Breastfeeding and Maternal Stroke Risk
by Anne Eglash MD, IBCLC, FABM
There is good evidence that women who breastfeed have a lower risk of high blood pressure and heart attacks when they are older. Risk factors for heart attacks are similar to those for strokes, so it would make sense to evaluate whether breastfeeding also reduces the maternal risk of stroke.
According to authors in the Women’s Health Initiative Observation Study, stroke is the third leading cause of death among US Hispanic and non-Hispanic black women over the age of 65. This 2010 study of approximately 80,000 postmenopausal women evaluated whether women who breastfed had a lower stroke rate compared to those who never breastfed, and whether the duration of breastfeeding modified that rate. Other underlying variables that affect risk of stroke were controlled for, such as smoking, weight, vitamin supplementation, and diet.
- They are more likely to work in jobs that are less supportive of breastfeeding.
- They earn less money.
- They have less social support.
- They have limited access to healthcare services.
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Abstract
Background:
Stroke is the third leading cause of death among US Hispanic and non‐Hispanic black women aged 65 and older. One factor that may protect against stroke is breastfeeding. Few studies have assessed the association between breastfeeding and stroke and whether this association differs by race and ethnicity.
Methods & Results:
Data were taken from the Women’s Health Initiative Observational Study with follow‐up through 2010; adjusted hazard ratios for stroke subsequent to childbirth were estimated with Cox regression models accounting for left and right censoring, overall and stratified by race/ethnicity. Of the 80 191 parous women in the Women’s Health Initiative Observational Study, 2699 (3.4%) had experienced a stroke within a follow‐up period of 12.6 years. The average age was 63.7 years at baseline. Fifty‐eight percent (n=46 699) reported ever breastfeeding; 83% were non‐Hispanic white, 8% were non‐Hispanic black, 4% were Hispanic, and 5% were of other race/ethnicity. After adjustment for nonmodifiable potential confounders, compared with women who had never breastfed, women who reported ever breastfeeding had a 23% lower risk of stroke (adjusted hazard ratio=0.77; 95% confidence interval 0.70‐0.83). This association was strongest for non‐Hispanic black women (adjusted hazard ratio=0.52; 95% confidence interval 0.37‐0.71). Further, breastfeeding for a relatively short duration (1‐6 months) was associated with a 19% lower risk of stroke (adjusted hazard ratios=0.81; 95% confidence interval 0.74‐0.89). This association appeared stronger with longer breastfeeding duration and among non‐Hispanic white and non‐Hispanic black women (test for trend P<0.01).
Conclusions:
Study results show an association and dose‐response relationship between breastfeeding and lower risk of stroke among postmenopausal women after adjustment for multiple stroke risk factors and lifestyle variables. Further investigation is warranted.