The social hysteria over breastfeeding has risen to a fever pitch in the past several years, yet for decades scientists have expounded the health benefits of this innate act that defines mammals from all other animals. While the overwhelming majority of health advantages from breastfeeding are passed along to the nursing child, recent studies have begun to uncover an array of benefits for breastfeeding mothers. For instance, new findings from investigators at the University of Kansas and Stanford University provides evidence that breastfeeding may reduce the risk for stroke in post-menopausal women who reported breastfeeding at least one child.
Results from the new study were published in the Journal of the American Heart Association through an article titled “Breastfeeding History and Risk of Stroke Among Parous Postmenopausal Women in the Women's Health Initiative.” Stroke is the fourth leading cause of death among women aged 65 and older and is the third leading cause of death among Hispanic and black women aged 65 and older. This is among the first studies to examine breastfeeding and a possible relationship to stroke risk for mothers, as well as how such a relationship might vary by ethnicity.
“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,” explains lead study investigator Lisette Jacobson, Ph.D., assistant professor in the department of preventive medicine and public health at the University of Kansas School of Medicine-Wichita.
In the current study, the research team analyzed 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 having breastfed. Among these women, 51% breastfed for one to six months, 22% for seven to 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 compiling all of their data, the researchers made some interesting discoveries. Adjusting for nonmodifiable stroke risk factors (such as age and family history), researchers found stroke risk among women who breastfed their babies was on average:
- 23% lower in all women
- 48% lower in black women
- 32% lower in Hispanic women
- 21% lower in white women
- 19% lower in women who had breastfed for up to six months.
Interestingly, the scientists found that a longer reported length of breastfeeding was associated with a greater reduction in risk.
Because the study was observational, it couldn't establish a cause-and-effect relationship between breastfeeding and lower stroke risk, 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. However, because the Women's Health Initiative is large, researchers were able to adjust for many characteristics, and the effects of breastfeeding remained strong.
“Our study did not address whether racial/ethnic differences in breastfeeding contribute to disparities in stroke risk,” Dr. Jacobson notes. “Additional research should consider the degree to which breastfeeding might alter racial/ethnic differences in 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.
“Breastfeeding is only one of many factors that could potentially protect against stroke. Others include getting adequate exercise, choosing healthy foods, not smoking, and seeking treatment if needed to keep your blood pressure, cholesterol, and blood sugar in the normal range,” Dr. Jacobson remarks.
Currently, the American Academy of Pediatrics and the World Health Organization recommend exclusive breastfeeding for six months, with the continuation of breastfeeding for one year or longer. The American Heart Association recommends breastfeeding for 12 months with the transition to other additional sources of nutrients beginning at about four to six months of age to ensure sufficient micronutrients in the diet.
“If you are pregnant, consider breastfeeding as part of your birthing plan and continue to breastfeed for at least six months to receive the optimal benefits for you and your infant,” Dr. Jacobson concludes.