The impact of body mass index and height on the risk for glioblastoma and other glioma subgroups: a large prospective cohort study

Background: Glioma comprises a heterogeneous group of mostly malignant brain tumors, whereof glioblastoma (GBM) represents the largest and most lethal subgroup. Body height and body mass index (BMI) are risk factors for other cancers, but no previous study has examined anthropometric data in relation to different glioma subgroups. Methods: This prospective cohort study includes 1.8 million Norwegian women and men between ages 14 and 80 years at baseline. Body weight and height were measured, and incident cases of glioma were identified by linkage to the National Cancer Registry. Cox regression analyses were performed to evaluate risk for different glioma subgroups in relation to anthropometric measures. Results: During 54 million person-years of follow-up, 4,382 gliomas were identified. Overweight and obesity were not associated with risk for any glioma subgroup. Height was positively associated with risk for GBM and all other gliomas (hazard ratio [HR] per 10 cm increase: 1.24; 95% confidence interval [CI], 1.17-1.31 and 1.18; 95% CI, 1.09-1.29) but not with the proxy for isocitrate dehydrogenase (IDH)-mutant glioma (HR, 1.09; 95% CI, 0.98-1.21). In further subgroup analyses, the effect of height on glioma risk varied significantly with positive associations for oligoastrocytoma (HR, 1.74; 95% CI, 1.20-2.53) and malignant glioma not otherwise specified (NOS) (HR, 1.42; 95% CI, 1.16-1.76, but not with diffuse astrocytoma (WHO grades II and III) or oligodendroglioma. Conclusion: This epidemiologic study consolidates height as a risk factor for GBM and other gliomas. It further indicates that this association is not universal for gliomas but may differ between different glioma subgroups.