Hormonal exposures and the risk of intracranial meningioma in women: a population-based case-control study

The association between oral contraception (OC) or hormone replacement therapy (HRT) and intracranial meningioma in women was investigated using a population-based, matched case-control study. Exposures for 143 cases and 286 controls matched on age within five years were obtained by interview. Diagnoses were confirmed histopathologically and estrogen and progesterone receptor assays conducted.Although risk of meningioma appeared modestly elevated in past OC users (OR = 1.5, 95% CI 0.8 – 2.7), and in current users (OR = 2.5, 95% CI 0.5 – 12.6), the confidence intervals were wide. No significant association between meningioma risk and duration of OC use was found. Likewise, risk of meningioma was only weakly associated with past use of HRT (OR = 0.7, 95% CI 0.4 – 1.3), and not at all with current use of HRT (OR = 1.0, 95% CI 0.5 – 2.2). Of 142 available specimens, 2 (1%) expressed estrogen receptors, whereas 130 (92%) expressed progesterone receptors (PR). OC use was associated with increased risk of a meningioma expressing less rather than more PR (OR = 3.2, 95% CI 1.3 – 8.0). Overall, in post menopausal women, HRT use appeared to confer a non-significant protective effect, and was not associated with low or high PR expressing meningiomas.This study found little evidence of associations between meningioma and exogenous hormone exposures in women but did suggest that some hormonal exposures may influence tumor biology in those women who develop meningioma.Meningiomas occur more frequently in women than men and have the highest incidence in the fifth and sixth decades of life[1,2]. Consistent with data from other studies in North America and Europe, we have previously reported the incidence of intracranial meningioma in western Washington State to be 3.2 per 100,000 person-years, with women comprising 69% of the meningioma diagnoses and the highest age- and gender-specific incidence of over 7 per 100,000 person-years in women 60 years or older[3].Research has focused o