Breastfeeding may reduce later MS risk for people with family history

Use of cow's milk or formula linked to increased risk of familial MS in study

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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A red teddy bear lies against the side of a sleeping infant.

In people with a family history of multiple sclerosis (MS), exclusive breastfeeding in the first months of life may reduce the risk of developing the disease later on, whereas use of cow’s milk or formula may increase MS risk.

That’s according to a new study on the potential impact of breastfeeding in sporadic versus familial MS, titled “Exclusive breastfeeding may be a protective factor in individuals with familial multiple sclerosis. A Population Registry-based case-control study.” It was published in Multiple Sclerosis and Related Disorders.

The researchers noted, however, that “exclusive breastfeeding was shown to be a protective factor for [familial MS] only in male population, for individuals breastfed [for at least] 4 months.” The team did note that a larger analysis of 15 studies, including theirs, “has shown a slight overall protective effect of breastfeeding on MS risk.”

Given these findings, “healthcare professionals may consider recommending prolonged exclusive breastfeeding for infants in families with a history of MS,” the researchers wrote.

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Investigating breastfeeding impact in sporadic vs. familial MS

The causes of MS remain incompletely understood. While genetic factors are thought to play a role in determining disease risk, lifestyle habits and environmental exposures also may affect the development of MS. Some studies have suggested that people who were breastfed as infants may be less likely to develop MS, but this link remains unproven.

Most people with MS have sporadic disease — referred to as sMS — meaning that the condition affects only one person in a biological family. But there also are cases of familial MS, or fMS, in which multiple close biological relatives develop MS, presumably due to shared genetic risk factors. To date, studies on the effects of breastfeeding in MS risk have not distinguished between these two types of MS.

Here, a team led by scientists in Serbia conducted a study that sought to find out whether the effect of breastfeeding on MS risk differs between those with sporadic or familial disease.

“Until now, the role of environmental factors, including breastfeeding, in the development of MS have been studied only in the general MS population, comprising both sporadic and familial cases. … In this report, we aimed to investigate whether breastfeeding might have a specific protective role in [people] with either fMS or sMS in comparison with healthy controls,” the scientists wrote.

The study included data on 131 people with fMS and an equal number with sMS, as well as controls without the disease. All of the controls were spouses or friends of the fMS patients. Each participant completed a standardized survey asking about any history of being breastfed.

Roughly three-quarters of participants in each of the three groups reported that they were breastfed exclusively in the first three months of life. But looking at the first six months of life, significantly more controls (73.4%) were exclusively breastfed compared with those with fMS (58.7%) or sMS (67.2%).

At ages older than six months, slightly more than half of controls and patients with sporadic disease were exclusively breastfed, but less than half of fMS patients were exclusively breastfed at older ages. The researchers noted that this was a significant difference.

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Difference in risk found to be statistically significant only in males

With data in hand, the researchers constructed statistical models to assess the relationship between breastfeeding status and MS risk.

The results showed no significant effect of breastfeeding on the risk of sporadic MS. But in cases of familial disease, exclusive breastfeeding for six months or longer was associated with a significantly reduced risk of MS.

Our findings indicate that breastfeeding might have a potential role in additionally reducing the risk of MS in infants with family history of the disease, although this protective effect may be limited to the male population.

When stratified by sex, this difference was statistically significant in males, but not females.

“Our findings indicate that breastfeeding might have a potential role in additionally reducing the risk of MS in infants with family history of the disease, although this protective effect may be limited to the male population,” the researchers wrote.

The models also indicated that, in fMS, people with a longer time spent breastfeeding tended to have a reduced risk of disease, while use of cow’s milk or infant formula was associated with increased risk of familial MS.

These findings “might indicate that infants in families with family history of MS should avoid the consumption of cow’s milk and infant formula in infanthood,” the researchers wrote.

The scientists highlighted that this was a fairly small study, and because familial MS is much rarer than the sporadic form, it’s difficult to find sample sizes large enough to detect meaningful associations. They stressed a need for further studies with more participants to verify these results.