Body mass index in patients with Multiple Sclerosis: a meta-analysis.

Background : The impact of nutrition and diet on the etiology of Multiple Sclerosis (MS) has been evaluated through a number of studies. Only a limited number reported findings on the association between body mass index (BMI) and MS. We systematically assessed whether BMI differs between MS patients and healthy individuals. Methods : The PubMed database was searched for available studies assessing the relationship between BMI and MS until April 2018. Random effects models were applied for evaluating the association of mean BMI between MS, relapsing-remitting MS (RRMS) patients, females, or males with MS, and their respective healthy control groups. Results : We included 25 studies. The mean BMI of MS patients during the course of the disease and RRMS patients was significantly different from the mean BMI of their healthy counterpart individuals [standardized mean difference (SMD) (95% confidence interval (CI)): -0.25 (-0.44, -0.06), PZ  = 0.01 and SMD (95%): -0.27 (-0.54, -0.01), PZ  = 0.04, respectively]. The mean BMI of females with MS was significantly differentfrom that of corresponding healthy females [SMD (95% CI): -0.52 (-0.96, -0.07), PZ  = 0.02]. Moreover, the mean BMI was significantly different between males with MS and healthy males [SMD (95% CI): -0.75 (-1.33, -0.18), PZ  = 0.01]. Conclusions : Statistically significantly lower mean BMI was revealed in the overall MS patients' group during the MS course than in healthy controls. The same difference was revealed in all parts of the meta-analysis demonstrating a significantly lower BMI in patients with RRMS, in females, and in males with MS, when compared to their respective healthy individuals.