Geographic and birth cohort associations of Kaposi's sarcoma among homosexual men in Canada.

The authors conducted an analysis of all 677 cases of Kaposi's sarcoma among the 3,047 cases of acquired immunodeficiency syndrome diagnosed in homosexual/bisexual men in Canada between 1980 and 1989. The proportion with Kaposi's sarcoma declined from 32.2% during 1980-1985 to 15.0% in 1989. The proportion with Kaposi's sarcoma was significantly higher in primary epidemic centers (Vancouver, Toronto, and Montreal) and in men in the 1945-1954 birth cohort independent of year of diagnosis. These data are consistent with an environmental cofactor for Kaposi's sarcoma which is likely to be a sexually transmitted agent.