Obesity is implicated in the development of multiple sclerosis (MS), but its effect on disability is less well-established. This study examined the effects of various obesity measures on MS severity in 12,584 MS cases, using Mendelian randomization to mitigate confounding. Results showed a significant association between higher genetically-determined body mass index (N = 806,834) and increased MS severity (P = 0.02). This finding was supported by additional measures of general obesity but not adiposity distribution. The convergence of this genetic evidence with prior observational studies strengthens the association between obesity and adverse long-term disability in MS, suggesting weight management as a potential therapeutic strategy. ANN NEUROL 2024.
