Handedness and risk of brain tumors in adults.

The objective of this study was to evaluate the relation between handedness, and the risk of malignant and benign brain tumors. Handedness has been hypothesized to serve as a behavioral marker of prenatal hormonal exposures or other factors that influence subsequent cancer risk. A case-control study was conducted at hospitals in three United States cities between 1994 and 1998. The cases were adult patients newly diagnosed with glioma (n = 489), meningioma (n = 197), or acoustic neuroma (n = 96), and the 799 frequency-matched controls were patients admitted to the same hospitals for a variety of nonmalignant conditions. Handedness was determined by interview. Unconditional logistic regression was used to estimate odds ratios (ORs) and calculate 95% confidence intervals (CIs). Persons who described themselves as left-handed or ambidextrous appeared to be at reduced risk of glioma relative to those who described themselves as right-handed (OR, 0.7; 95% CI, 0.5-0.9). The association was similar for men and women, and for left-sided and right-sided tumors. Neither meningioma (OR, 0.9; CI, 0.6-1.5) nor acoustic neuroma (OR, 0.9; CI, 0.5-1.7) showed significant associations with handedness. These findings require confirmation but raise the possibility that early neurodevelopmental events or genetic factors related to handedness also influence the risk of glioma among adults.