Body mass index, physical activity, and risk of adult meningioma and glioma: A meta-analysis.

OBJECTIVE: Whether adiposity and lack of physical activity affect the risk for developing meningioma and glioma is poorly understood. Our objective was to characterize these associations in detail.

METHODS: We conducted a systematic review and meta-analysis of adiposity and physical activity in relation to meningioma and glioma using cohort and case-control studies published through February 2015. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS: We identified 12 eligible studies of body mass index (BMI) and 6 studies of physical activity, comprising up to 2,982 meningioma cases and 3,057 glioma cases. Using normal weight as the reference group, overweight (summary relative risk [RR] = 1.21, 95% confidence interval [CI] = 1.01-1.43) and obesity (RR = 1.54, 95% CI = 1.32-1.79) were associated with increased risk of meningioma. In contrast, overweight (RR = 1.06, 95% CI = 0.94-1.20) and obesity (RR = 1.11, 95% CI = 0.98-1.27) were unrelated to glioma. Similarly, dose-response meta-analyses revealed a statistically significant positive association of BMI with meningioma, but not glioma. High vs low physical activity levels showed a modest inverse relation to meningioma (RR = 0.73, 95% CI = 0.61-0.88) and a weak inverse association with glioma (RR = 0.86, 95% CI = 0.76-0.97). Relations persisted when the data were restricted to prospective studies, except for the association between physical activity and glioma, which was rendered statistically nonsignificant (RR = 0.91, 95% CI = 0.77-1.07).

CONCLUSIONS: Adiposity is related to enhanced risk for meningioma but is unassociated with risk for glioma. Based on a limited body of evidence, physical activity is related to decreased risk of meningioma but shows little association with risk of glioma.