Meningiomas occur more commonly in females. The coincidence between meningioma 
and breast cancer and case reports of tumor growth during pregnancy support a 
hormonal hypothesis. A case control study was conducted to investigate this. 
Female subjects treated between 1987 and 1992 were identified from 3 hospitals 
in the Chicago area. Female spouses of male back pain patients were recruited as 
controls. A self-administered mail questionnaire focused on exogenous, 
endogenous and other hormonal factors, personal and family medical history as 
well as radiation exposures. Odds ratios and 95% confidence intervals were 
estimated using crude, stratified and multivariable logistic models including 
219 cases and 260 controls. Participation rates were 86% among cases and 75% 
among controls. An increased odds ratio (OR) was observed comparing African 
Americans to Caucasians [OR = 2.4, 95% confidence interval (CI) = 1.0-6.1]. A 
protective effect was observed for pregnancy, which increased with number and 
age at first pregnancy. The odds ratio for 3 or more pregnancies compared to 
none was 0.3 (95% CI = 0.2-0.6). Age at menarche or total period of hormonal 
activity was not protective. Ever smokers showed a decreased odds ratio for 
meningioma (OR = 0.6, 95% CI = 0.4-0.9). The increased odds ratios with African 
Americans was retained in post-menopausal women, while the protective odds 
ratios for pregnancy, smoking and oral contraceptives (OCs) became stronger in 
pre-menopausal women. The pattern by duration and timing of use does not suggest 
an etiologic role for OCs or hormone replacement therapy. These data add to the 
evidence that factors known to influence endogenous hormones (pregnancy and 
indirectly smoking) may have protective effects for meningiomas primarily in 
premenopausal women.