Intracranial meningiomas arise from the meninges and typically have be
nign histologic findings. They constitute approximately 20% of all int
racranial tumors. Their incidence increases with age, and they affect
women more commonly than men. The annual incidence per 100,000 people
ranges from two to seven for women and from one to five for men. Since
the first study was published in 1970, only eight major epidemiologic
studies have been done that attempted to identify risk factors for me
ningioma. Ionizing radiation and head trauma have emerged as the most
promising etiologic risk factors. In these studies, radiation doses as
low as 1-2 Gy have been associated with increased risk. The role of d
ental radiographs has been suggested in some studies but not supported
in others. An explanation for the apparent excess of meningiomas in w
omen remains obscure. The potential effects of endogenous or exogenous
sex hormones on tumor induction or growth remain unexplored in epidem
iologic studies. More should be learned about the risk factors for men
ingioma in search of opportunities for prevention.