Possible interaction between ionizing radiation, smoking, and gender in the causation of meningioma.

Data on the association between smoking and meningioma are inconsistent. The aim of this study was to assess the role of smoking in radiation- and non-radiation-related meningiomas. The study was designed as a 4-group case-control study, balanced for irradiation, including 160 irradiated meningioma case patients, 145 irradiated control subjects, 82 nonirradiated case patients, and 135 nonirradiated control subjects. The sources of these groups included a cohort of individuals who underwent radiotherapy (mean dose, 1.5 Gy to the brain) during childhood for treatment of tinea capitis, claims filed for radiation damage in the framework of a compensation law, and the Israel Cancer Registry. All tests of statistical significance were 2-sided. A statistically significantly elevated risk of meningioma was found among men who had ever smoked, compared with those who were never smokers (odds ratio [OR], 2.13; 95% confidence interval [CI], 1.09-4.15), increasing with smoking pack-years from 1.67 to 2.69 for <10 to >20 pack-years, respectively. Among women, an interaction between radiation and smoking was observed, expressed by a significant protective effect for meningioma (OR, 0.32; 95% CI, 0.14-0.77), with a strong dose-response association (P < .01) in non-irradiated women and a nonsignificant increased risk of meningioma among those who were irradiated (OR, 1.23; 95% CI, 0.68-2.23). Variation in the association between smoking and meningioma may be explained by effects of distinct host factors, such as past exposure to ionizing radiation and/or hormonal factors.