RISK-FACTORS FOR KAPOSIS-SARCOMA IN HIV-POSITIVE SUBJECTS IN UGANDA

Background: Kaposi's sarcoma (KS) is associated epidemiologically with HIV infection and with human herpesvirus 8 (HHV-8 or KSHV). Both KS a nd HIV infection are common in Uganda. We conducted a case-control stu dy of 458 HIV-seropositive Ugandan adults with KS and 568 HIV-seroposi tive subjects without KS to examine risk factors for HIV-associated KS . Methods: We recruited newly diagnosed adult KS cases from five hospi tals in Kampala, Uganda and controls from a large referral clinic for HIV infection at Mulago Hospital. All cases and controls were counsell ed and tested for HIV and answered an interviewer-administered questio nnaire about their home, socioeconomic conditions, lifestyle and sexua l behaviour before they became ill. Only HIV-seropositive subjects wer e included in the analysis. Results: There were 295 males and 163 fema les with KS and 227 mate and 341 female controls. Age distribution was similar but there was a higher proportion of cases (45%) than control s (29%) residing in rural regions of Uganda. KS cases were more likely than controls to have a higher level of education (chi(2) for trend, 4.8; P = 0.03), to have occupations associated with affluence [chi(2) for heterogeneity, 17.3 on 5 degrees of freedom (df); P = 0.004] and t o come from larger settlements [adjusted odds ratio (OR) for settlemen ts of >1000 venus 10-99 houses, 1.8; 95% confidence interval (CI), 1.1 -3.0]. Cases were more likely than controls to have high household inc ome (chi(2) for trend, 32.6; P < 0.001) and other markers of urban or rural wealth such as owning several cows (chi(2) for trend, 9.5; P = 0 .002). Cases were more likely to travel away from home (adjusted OR, 1 .6, 95% CI, 1.1-2.3) and more likely to have spent increasing time in contact with water (chi(2) for trend, 12.3; P < 0.001). Few indices of sexual behaviour were related to risk of KS, including reported numbe r of sexual partners. Cases were more likely than controls to be marri ed to one rather than several spouses (adjusted OR, 1.6; 95% CI, 1.2-2 .2) and to have reported a history of sexually transmitted diseases (S TD) (adjusted OR, 1.6; 95% CI, 1.2-2.3). Conclusions: Among HIV-infect ed subjects, KS cases are characterized by better education and greate r affluence, compared with controls. Urban address, travel away from h ome, exposure to water, monogamous marriage and self-reported STD were also more frequent among KS cases than controls. The higher socio-eco nomic status of persons with HIV and KS may be a marker for enhanced e xposure to a possibly sexually transmitted agent, or for a delayed exp osure to a childhood infection. The risk posed by exposure to water am ong KS cases requires further study.