Excess Body Weight during Childhood and Adolescence Is Associated with the Risk of Multiple Sclerosis: A Meta-Analysis

BACKGROUND AND AIM: Several epidemiological studies have reported the association between obesity and multiple sclerosis (MS). METHODS: A literature search of the observational studies, published as original articles in English before December 2015, was performed using electronic databases. RESULTS: Five observational studies were included, of which 3 were case-control studies and 2 were cohort studies. The pooled relative risk (RR) for overweight and obesity during childhood and adolescence compared with normal weight (body mass index = 18.5-24.9 kg/m2) was 1.44 (95% CI 1.22-1.70) and 2.01 (95% CI 1.63-2.48), respectively. In subgroup analyses, we found that excess body weight during childhood and adolescence increased the risk of MS in the female group (overweight: pooled RR = 1.62, 95% CI 1.35-1.94; obesity: pooled RR = 2.25, 95% CI 1.77-2.85), but not in the male group (overweight: pooled RR = 1.19, 95% CI 0.91-1.55; obesity: pooled RR = 1.22, 95% CI 0.79-1.90). CONCLUSIONS: Excess body weight during childhood and adolescence was associated with an increased risk of MS; severe obesity demonstrated a stronger risk. A statistically significant association was found in the female group, but not in the male group.