Abnormal body mass index is associated with risk of multiple sclerosis: A systematic review and meta-analysis

It is widely recognized that obesity is characterized by a chronic low-grade inflammatory condition. In the context of childhood and adolescent obesity, there is also a noteworthy correlation with elevated levels of inflammatory markers. These markers signify a proinflammatory state that may have relevance to the development of MS. We aim to comprehensively explore the relationship between childhood, adolescent, and adulthood obesity and the risk of developing multiple sclerosis (MS).

We performed a comprehensive systematic review and meta-analysis of relevant literature through online search in databases like MEDLINE, Scopus, EMBASE, and Web of Science. We included studies that 1) provided information on multiple body mass index (BMI) categories before the onset of MS (Pre-MS BMI) and 2) had a healthy control group.

The overall risk ratio (RR) in underweight people is 0.96 (95 % CI: 0.85 to 1.09, I² = 0 %), indicating no significant impact on MS risk. Individuals who are overweight or obese, on the other hand, were at a higher risk of MS, with RRs of 1.38 (95 % CI: 1.27 to 1.49, I² = 49 %) and 1.88 (95 % CI: 1.50 to 2.35, I² = 76 %), respectively. There is a significantly greater risk of MS for people who are obese than for those who are overweight.

Overweight and obese individuals are at increased risk for MS, emphasizing the significance of weight status in MS susceptibility. Our findings support the hypothesis that obesity-related mechanisms-such as chronic inflammation, immune responses, and changes in gut microbiota and adipokines-may play a role in this association.