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KUSM-W > Newsroom > Study led by KUSM-W faculty member makes international headlines

Study led by KUSM-W faculty member makes international headlines

August 24, 2018

Lisette T. Jacobson, Ph.D., MPA, M.A.

A new study led by a University of Kansas School of Medicine-Wichita faculty member is making international headlines for its findings that show breastfeeding may help protect mothers from stroke.

Lisette Jacobson, Ph.D., MPA, M.A., assistant professor in KU School of Medicine-Wichita's Department of Preventive Medicine & Public Health, is the lead author on the study, which was published in Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association.

Co-authors include Tracie Collins, M.D., MPH, MHCDS, professor and chair of KU School of Medicine-Wichita's Department of Preventive Medicine & Public Health; Kim Kimminau, Ph.D., associate professor in Family Medicine at KU School of Medicine in Kansas City; and Karen Wambach, Ph.D., director of the Ph.D. program at the KU School of Nursing in Kansas City.

According to the study, 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.

"Some studies have reported that breastfeeding may reduce the rates of breast cancer, ovarian cancer and risk of developing Type 2 diabetes in mothers," Jacobson said. "Recent findings point to the benefits of breastfeeding on heart disease and other specific cardiovascular risk factors."

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.

Researchers 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 percent reported ever having breastfed. Among these women, 51 percent breastfed for one to six months, 22 percent for seven to 12 months and 27 percent 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 percent lower in all women,
  • 48 percent lower in black women,
  • 32 percent lower in Hispanic women,
  • 21 percent lower in white women, and
  • 19 percent lower in women who had breastfed for up to six months. A longer reported length of breastfeeding was associated with a greater reduction in risk.

"If you are pregnant, please 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," Jacobson said.

"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.

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, Jacobson said.

"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," Jacobson said.

The study was also limited by the relatively small number of strokes that occurred during the follow-up period (just 3.4 percent of the women experienced a stroke during the study period and 1.6 percent 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.

Currently, the American Academy of Pediatrics and the World Health Organization recommend exclusive breastfeeding for six months, with continuation of breast feeding for one year or longer. For babies' health, the American Heart Association recommends breastfeeding for 12 months with transition to other additional sources of nutrients beginning at about four - six months of age to ensure sufficient micronutrients in the diet.

The Heartland Institute for Clinical and Translational Research and the Wichita Center for Graduate Medical Education-Kansas Bioscience Authority funded the study. The WHI was supported by the National Health, Lung, and Blood Institute. Co-authors are Erinn M. Hade, Ph.D.; Tracie C. Collins, M.D., MPH, MHCDS; Karen L. Margolis, M.D., MPH; Molly E. Waring, Ph.D.; Linda V. Van Horn, Ph.D., R.D.; Brian Silver, M.D.; Maryam Sattari, M.D., M.S.; Chloe E. Bird, Ph.D.; Kim Kimminau, Ph.D.; Karen Wambach, Ph.D.; and Marcia L. Stefanick, Ph.D.

KU School of Medicine-Wichita
Last modified: Aug 25, 2018
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