Blood pressure and other metabolic syndrome factors and risk of brain tumour in the large population-based Me-Can cohort study.

OBJECTIVES: Brain tumour has few established determinants. We assessed to which extent risk of brain tumour was related to metabolic syndrome factors in adults.
METHODS: In the Me-Can project, 580 000 individuals from Sweden, Austria, and Norway were followed for a median of 10 years after baseline measurement. Data on brain tumours were obtained from national cancer registries. The factors of metabolic syndrome (BMI, SBP and DBP, and blood levels of glucose, cholesterol, and triglycerides), separately and combined, were analysed in quintiles and for transformed z-scores (mean transformed to 0 and standard deviation to 1). Cox proportional hazards multivariate regression models were used, with corrections for measurement error.
RESULTS: During follow-up, 1312 primary brain tumours were diagnosed, predominantly meningioma (n = 348) and high-grade glioma (n = 436). For meningioma, the hazard ratio was increased for z-scores of SBP [hazard ratio = 1.27 per unit standard deviation, 95% confidence interval (CI) 1.03-1.57], of DBP (hazard ratio = 1.29, 95% CI 1.04-1.58), and of the combined metabolic syndrome score (hazard ratio = 1.31, 95% CI 1.11-1.54). An increased risk of high-grade glioma was found for DBP (hazard ratio = 1.23, 95% CI 1.01-1.50) and triglycerides (hazard ratio = 1.35, 95% CI 1.05-1.72). For both meningioma and high-grade glioma, the risk was more than double in the fifth quintiles of DBP compared to the lowest quintile. For meningioma this risk was even larger for SBP.
CONCLUSION: Increased blood pressure was associated with risk of brain tumours, especially of meningiomas.