Risk factors for nodular sclerosis and other types of Hodgkin's disease.

The age-adjusted incidence rates of nodular sclerosis in Los Angeles County from 1972 to 1975 were 58% lower in Mexican-Americans and 42% lower in blacks than in other whites. They were the same for each sex among other whites and the curve of age-specific incidence peaked in young adulthood. The incidence of nodular sclerosis was directly associated with social class. In contrast, the rates for other histological varieties of Hodgkin's disease (lymphocyte predominance, mixed cellularity, lymphocyte depletion) were only 12% lower in Mexican-Americans but 34% lower in blacks. In other whites, the rates were 92% higher in men and increased gradually with age while there were no clear trends with social class. These characteristics support the hypothesis that, at least for purposes of etiology, the nodular sclerosis form of this disease should be considered a distinct entity. Self-administered questionnaire were completed by 218 of the 1972 to 1973 Hodgkin's disease patients and 218 individually matched neighbourhood controls. Significantly high risk ratios for Hodgkin's disease were found for prior appendectomy (risk ratios = 1.9, p = 0.01) and for past amphetamine use (risk ratios = 3.0, p = 0.01). The elevated risk associated with amphetamine use had been found in a previous study.