Breastfeeding May Reduce MS Risk for Individuals With Family History

Breastfeeding has a protective effect on male infants with a family history of multiple sclerosis (MS), according to study findings published in the journal Multiple Sclerosis and Related Disorders.

A combination of environmental and genetic factors can lead to MS. While familial MS (fMS) is defined as MS in a person with first-, second-, or third-degree relatives with MS, sporadic MS (sMS) is an individual who has MS with no family history of MS.

Research regarding the association between breastfeeding and MS risk is unclear, although most studies suggest that breastfeeding has a protective effect on MS occurrence. Researchers conducted a study to evaluate the differences in environmental and genetic risk factors for MS development and to determine what role breastfeeding has on MS risk. 

The researchers collected data from a case-control study conducted at the Clinic of Neurology at the University Clinical Center of Serbia in Belgrade between March 2021 and January 2023. Individuals who had relatives with MS beyond the third degree were excluded from the study. Participant cases of sMS were matched to patients in the fMS group, and spouses or non-blood-related friends of individuals with fMS were included in the study as the healthy control group. 

Of the 393 participants in the study, 131 individuals had fMS, 131 had sMS, and 131 were healthy control group patients. There were was a greater proportion of female participants in the fMS (71.8%) and sMS (71.8%) groups compared with the healthy control group (35.9%). 

Compared with individuals with fMS (58.7%) and sMS (67.2%; P =.045), a higher proportion of participants in the control group (73.4%) were exclusively breastfed in the first 6 months of life.

When compared with the fMS group, a greater number of participants in the sMS group were exclusively breastfed longer than 6 months (relative risk ratios [RRR], 2.01; 95% CI, 1.22-3.32).

Among the 131 patients in the fMS group, 93 participants had a first-degree relative with MS (71.0%), 26 participants (19.8%) had a second-degree relative with MS, and 12 participants (9.2%) had a third-degree relative with MS. Of these cases, 25 (19.1%) of participants had more than one relative with MS. 

Stratification by sex revealed that exclusive breastfeeding is a protective factor for male patients in the fMS group if breastfed for at least 4 months. There were no associations observed for breastfeeding and MS risk protection in the female population. 

Some factors associated with fMS risk include the use of alternative milks, including infant formula or cow’s milk, at any other time in infancy regardless of breastfeeding status.

Study limitations are recall bias, the inability to select an adequate control group, and the genotype of individuals potentially impacting the effects of breastfeeding. 

“These findings implicate the importance of influence of cultural factors on breastfeeding practices, which differ significantly between populations,” the researchers concluded.