Menopausal Hormone Therapy and Risk of Central Nervous System Tumours: a UK-based Nested Case-control Study
METHODS: We conducted a nested case-control study within the UK General Practice Research Database (GPRD) cohort to examine the relation between prescription for hormone therapy (HT) for the menopause and the incidence of CNS tumours. Our study included women aged 50-79 years registered in the GPRD during 1987-2011. Controls were matched to cases in a ratio of 4:1 for year of birth, general practice and observation period. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression.
RESULTS: During a mean observation period of 8.6 years, 3500 CNS tumours were recorded, of which 689 were glioma, 1197 meningioma, 439 acoustic neuroma, and 273 were pituitary tumours. Women prescribed HT had a significantly increased risk of any CNS tumour (RR for 1+ vs. no HT prescriptions = 1.2, 95%CI=1.1-1.3), and risk between tumour types did not differ for specified glioma, meningioma, acoustic neuroma, and pituitary tumours (heterogeneity-p = 0.6). In women with a current prescription for HT, the risks for all CNS tumours and for specified types were higher for oestrogen-only HT than for combined oestrogen-progestagen HT. Meningioma risk did not vary by type of HT.
CONCLUSIONS: Findings from the GPRD study suggest that HT for the menopause may increase the risk of CNS tumours, with the excess risk largely confined to oestrogen-only HT.