Cigarette smoking and risk of adult leukemia.

A case-control study investigated the relation between cigarette smoking and histologic subtypes of adult leukemia in Missouri in 1984-1990. Among males, elevated risks associated with ever smoking were observed for acute nonlymphocytic leukemia (odds ratio (OR) = 1.5; 95% confidence interval (CI) 1.1-2.0) and acute myelocytic leukemia (OR = 1.5; 95% CI 1.1-2.1). Females also showed an increased risk of acute nonlymphocytic leukemia associated with ever smoking (OR = 1.4; 95% CI 1.0-1.9), with an increasing trend in risk by level of smoking (p less than 0.01). Attributable risk estimates of the proportion of acute nonlymphocytic leukemia caused by smoking were 33 percent in males and 29 percent in females. Elevations in risk were not apparent for chronic forms of leukemia. The findings support the hypothesis that some types of leukemia may be etiologically related to cigarette smoking.