More than 2.3 million people worldwide are living with multiple sclerosis, a debilitating and progressive disease that often ends in severe disability and premature death. Thanks to the collaborative efforts from a team of researchers in Canada and the UK, a possible link has been unearthed between unhealthy weight gain and multiple sclerosis. Their findings, published in the journal PLOS Medicine, may lead to a public health intervention in the fight against obesity, and the increased disease risks it carries.

“These findings may carry important public health implications because of the high prevalence of obesity in many countries,” the study’s authors wrote. “For instance, approximately 17 percent of youth and 35 percent of adults living in the United States are considered to be obese. Therefore, the identification of elevated BMI as a susceptibility factor for MS places a high proportion of the population at a relatively higher risk for MS.”

For the study, researchers reviewed 125 different studies with roughly 339,224 individuals. They studied each participant’s genome and searched for markers that indicated multiple sclerosis. Next, they calculated participants’ body mass indexes (BMI) in order to reveal the obese patients and any weight gain they may have had over time. Those who experienced a change in BMI from being overweight to obese had an approximate 40 percent increased risk for developing multiple sclerosis. Put in perspective: that means that if an average size woman weighing 150 pounds were to gain 30 more pounds, she would not only put herself at an increased risk for heart disease and Type 2 diabetes, but also a much greater chance of developing multiple sclerosis.

Obese MS
Obesity may be one of the risk factors for multiple sclerosis, especially in young people. Photo courtesy of Jeff J Mitchell/ Getty Images

According to the National MS Society, multiple sclerosis strikes in women two to three times more often than it does in men, however experts can’t pinpoint why. In fact, since they began studying the disease in 1975, they haven’t been able to figure out a potential root cause, but the disease is suspected to stem from an environmental influence, such as low vitamin D, cigarette smoking, and now possible unhealthy weight gain and obesity. The disease is both chronic and unpredictable, leading to a wide variety of symptoms including blurred vision, loss of balance, poor coordination, slurred speech, tremors, numbness, extreme fatigue, problems with memory and concentration, paralysis, and blindness.

Previous research published in the journal Neurology in 2014 had found a connection between being overweight at a young age and a susceptibility to developing multiple sclerosis, however, this is the first time researchers have located a genetic link. The researchers in 2014 believed the link may be inflammation because of obesity’s proclivity to chronic inflammation and other triggers that may cue the immune system to attack itself.

Because multiple sclerosis often affects young to middle-aged adults between the ages of 20 and 50, the study’s authors said that we have yet another reason to prevent obesity because the study results suggest that obesity in early life is indeed causally related to multiple sclerosis risk,

Source: Mokry LE, Ross S, Timpson NJ, Sawcer S, Smith GD, and Richards JB. Obesity and Multiple Sclerosis: A Mendelian Randomization Study. PLOS Medicine . 2016.