Multiple sclerosis is associated with worse body composition across compartments: Results from a systematic review and meta-analysis

Background: There is conflicting evidence regarding specific differences in body composition (i.e., body fat, lean, and bone) between people with multiple sclerosis (MS) and non-MS controls. The objective of this meta-analysis was twofold: (1) quantify overall and compartment-specific differences in body composition between people with MS and controls; and (2) identify individual and disease-specific moderators of any differences in body composition between groups. Methods: A search of five electronic databases (MEDLINE, EMBASE, Cochrane Central, CINAHL, and Scopus) was performed by an information specialist. Results: Overall, 180 effects were derived from 37 studies, 155 (86.1 %) of which were negative, with a mean effect ∆ of -0.39 (95 %CI: -0.46, -0.32, Z = -10.86, p < 0.001) suggesting poorer overall body composition in people with MS. Disability status was significantly associated with overall effect size (β = 0.31, Z = 4.33, p < 0.0001); effects were significantly larger at higher disability levels. Regarding body fat, 55/61 (90.2 %) effects were negative, resulting in a mean effect ∆ of -0.32 (95 %CI: -0.43, -0.21, Z = -5.72, p < 0.001). With regards to lean tissue, 38/43 (88.4 %) effects were negative, with a mean effect ∆ of -0.38 (95 %CI: -0.56, -0.21, Z = -4.28, p < 0.001). Lastly, 62/76 (81.6 %) effects for bone mineral density were negative, with a mean effect ∆ of -0.44 (95 %CI: -0.55, -0.34, Z = -8.28, p < 0.001). Conclusions: Current evidence supports poorer overall and compartment-specific body composition in people with MS, and this may be particularly relevant at higher disability. Strategies for managing body composition in MS should consider the need for maintaining lean mass and bone health, while managing obesity.