Hormone replacement therapy and risk of meningioma in women: a meta-analysis

The relationship between hormone replacement therapy (HRT) and the incidence of meningioma in women has been investigated in several epidemiologic studies, but their results were not entirely consistent. Here, we performed a meta-analysis of case-control and cohort studies to analyze this association. The PubMed database was searched from inception to 30 September 2012 to identify relevant studies that met pre-stated inclusion criteria. We also reviewed reference lists from the retrieved articles. Two researchers evaluated study eligibility and extracted the data independently. Odds ratios (ORs) or relative risks and 95 % confidence intervals (CIs) were extracted and pooled using the fixed-effect or random-effects models. A total of 11 studies (six case-control and five cohort studies) were included in this meta-analysis, involving 1,820,954 participants, of whom 3,249 had meningioma. When compared to never users of HRT, the pooled OR with ever users for meningioma was 1.29 (95 % CI 1.03-1.60). Sensitivity analyses restricted to postmenopausal women yielded similar results (OR: 1.22; 95 % CI 1.02-1.46). Subgroup analyses showed that the pooled ORs were 1.27 (95 % CI 1.08-1.49, p < 0.05) and 1.12 (95 % CI 0.95-1.32) for current and past users of HRT, respectively. Hormone replacement therapy use is associated with an increased risk of meningioma in women, as well as in postmenopausal women. Besides, the significant risk elevation is present in current users but not in past users. Future research should attempt to establish whether this association is causal and to clarify its mechanisms.