Women who breastfeed at least one child may have a reduced risk of suffering a stroke later in life, a new study has found.

A stroke occurs when the blood supply to the brain is interrupted, depriving it of oxygen and nutrients. As a result, some brain cells die and others are damaged, and this can affect body functions, such as movement, learning and communication.

Every year in Ireland, some 10,000 people suffer a stroke and 2,000 die as a result. Thousands more are left with stroke-related disabilities.

While previous studies have suggested that breastfeeding may reduce rates of some types of cancer in mothers, more recent studies have also suggested that breastfeeding may benefit cardiovascular health.

US researchers decided to look into the specific role of breastfeeding, making this one of the first studies to investigate its potential relationship with stroke risk.

They analysed data relating to over 80,000 women who were taking part in an ongoing study of post-menopausal women. The average age of the participants was 63 years and all had delivered at least one baby. Some 58% had breastfed at some stage.

Among those who breastfed, 51% had breastfed for at least one six-month period, 22% for seven to 12 months and 27% for 13 months or more.

After taking into account factors that may have affected the results, such as family history of stroke, the researchers found that the risk of stroke was 23% lower among all women who breastfed their babies.

Among black women, this figure jumped to 48%.

Among women who breastfed for less than six months, the risk of stroke was 19% lower.

"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," commented the study's lead author, Dr Lisette T. Jacobson, of the University of Kansas School of Medicine-Wichita.

The researchers acknowledged that as this study was observational, it could not establish a cause-and-effect relationship between breastfeeding and lower stroke risk. However they noted that because so many participants were involved, they were able to adjust for many characteristics, and the effects of breastfeeding remained strong.

"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 added.

Details of these findings are published in the Journal of the American Heart Association.