Black-white differences in Hodgkin's disease incidence in the United States by age, sex, histology subtype and time.

Black-white differences in Hodgkin's disease (HD) occurrence have been reported in older US mortality statistics and in limited international data, suggesting either genetic or socioeconomic determinants of susceptibility. However, there has been no evaluation with reliable data of the interracial incidence patterns by age, sex, and histologic subtype, that are prerequisite to understanding the causes of such variation. This project utilized 15 years of recent, high quality, incidence data from well-defined black and white US populations to calculate age-, sex-, and histology-specific rates of HD by race over time. Rates were somewhat lower for blacks (N = 593) than whites (N = 8,541) of both sexes, except among young boys. For blacks, age-specific incidence curves were slightly bimodal, although less than for whites; the male excess of HD was larger; and rates among women were low at all ages. For each histology subtype, blacks had lower incidence than whites; however, for the first time, nodular sclerosis was found to be the most common variant for both races. Between 1969-74 and 1980-84, HD rates declined in whites over age 55 but increased in white young adult women; among blacks, rates decreased slightly for boys and young adult men, the latter likely due to improving population enumeration. These findings confirm some interracial differences noted previously in HD. For blacks, they also reveal an incipiently bimodal age incidence and more prominent nodular sclerosis subtype occurrence that support a strong role for environmental factors in racial variation of this lymphoma.