Fractures of the distal forearm (wrist) are among the most common of all fractures. While evidence exists concerning risk factors for wrist fracture among women, little is known about risk factors among men. This study examines the relation of lifestyle characteristics (cigarette smoking, alcohol consumption, relative weight) as well as body height and handedness to the risk for fracture in a male population that has been followed up for 6 years. The 51,529 men, who were between the ages of 40 and 75 years in 1986, were participants in the Health Professionals Follow-up Study, a national prospective cohort study. In 271,552 person-years of follow-up, 271 respondents reported a wrist fracture. The risk for wrist fracture in this population did not vary with age. Cigarette smoking, alcohol consumption, body height, and relative weight also were not related to risk for wrist fracture. Handedness, which was divided into four mutually exclusive categories (right-handed, left-handed, forced to change, and ambidextrous), was significantly associated with wrist fracture. Left-handers had a multivariate relative risk for wrist fracture 1.56 times that of right-handers (95% confidence interval 1.02-2.37), and men who reported they had been forced to change from left-handed to right-handed had a multivariate relative risk 2.47 times greater than right-handers (95 percent confidence interval 1.21-5.04).