The longer women breastfeed, the lower their risk for multiple sclerosis

Added to the many health benefits breastfeeding confers on women, researchers have found that breastfeeding longer may lower a woman’s risk of developing multiple sclerosis (MS), according to results published in the journal Neurology.

“This is another example of a benefit to the mother from breastfeeding,” said lead author Annette Langer-Gould, MD, PhD, Kaiser Permanente Southern California, Pasadena, CA, and member, American Academy of Neurology. “Other health benefits include a reduced risk of breast cancer, ovarian cancer, type 2 diabetes, and heart attack.”

Previous studies have shown that women with MS have significantly fewer MS relapses during pregnancy and while exclusively breastfeeding.

“Many experts have suggested that the levels of sex hormones are responsible for these findings, but we hypothesized that the lack of ovulation may play a role, so we wanted to see if having a longer time of breastfeeding or fewer total years when a woman is ovulating could be associated with the risk of MS,” said Dr. Langer-Gould.

In the MS Sunshine Study, Dr. Langer-Gould and colleagues sought to assess whether women who breastfeed their infants longer or have fewer years ovulating were at lower risk of developing MS.

From the membership of Kaiser Permanente Southern California, researchers included 397 women with newly diagnosed MS or clinically isolated syndrome (CIS), a precursor of MS, and 433 matched controls. They administered a structured, in-person questionnaire to collect information on pregnancies, breastfeeding, and hormonal contraceptive use (behavioral factors) and age at menarche, menopause, amenorrhea (biological factors).

In women who had live births, they found a reduced risk of MS/CIS in those who had a cumulative duration of breastfeeding of ≥ 15 months (adjusted OR: 0.47; 95% CI: 0.28-0.77; P=0.003) compared with 0 to 4 months of breastfeeding).

No significant associations were seen between the risk of MS/CIS and total ovulatory years, gravidity, parity, episodes of amenorrhea, hormonal contraceptive use, or age at first birth.

“This study provides more evidence that women who are able to breastfeed their infants should be supported in doing so,” concluded Dr. Langer-Gould. “Among the many other benefits to the mother and the baby, breastfeeding may reduce the mother’s future risk of developing MS.”

This study was supported by the National Institute of Neurological Disorders and Stroke.