Factors associated with sexual risk behaviour among heterosexual, homosexual and bisexual males in Sao Paulo, Brazil.

This study assesses the role of factors associated with sexual risk behaviour and HIV infection in a sample of males in Sao Paulo, Brazil. In particular it considers: a) the influence of HIV serostatus on sexual behaviour and b) the influence of sexual identity on sexual behaviour. This generates the following comparison groups: a) HIV seronegative and HIV seropositive males and b) heterosexuals, homosexuals and bisexuals. This was a cross-sectional study carried out in Sao Paulo, Brazil, from August 1994 to February 1995. It examined a sample of 236 participants, including both HIV seronegative (n = 150) and HIV seropositive (n = 86) males recruited from public health centres. For HIV seropositive participants, the inclusion criterion was to have never experienced any opportunistic infections. For HIV seronegative participants, the criterion was to have received a negative HIV test result directly before interview. Information was obtained by verbal administration of a questionnaire, including questions relating to demographic aspects, HIV and AIDS related knowledge, sexual identity, alcohol and drug use, sexual behaviour, and perceived risk of HIV infection. Variables were selected from psycho-social models and from findings from previous studies investigating sexual risk behaviour. Because preventing HTV involves a partner and considerable risks, inclusion of demographic, personal, interpersonal and situational components may provide a more comprehensive assessment of the determinants of HIV preventive behaviour. Chi-square analysis revealed that a lower proportion of seropositives engaged in overall sexual activity (x2 = 10.68, df = 1, p < 0.001) and t test analysis revealed that seropositives engaged in lower frequency of penetrative practices (t = 2.28, df = 220.49, p<0.05). Heterosexuals reported higher frequency of penetrative practices than homosexuals and bisexuals (F (2, 194) = 8.667, p < 0.001). Sexual behaviour with female partners was found to be less risky among bisexuals than heterosexuals. Bisexuals reported lower frequency of vaginal intercourse with both regular (t = 6.07, df = 50.63, p < 0.001) and casual (t = 3.03, df = 27.09, p < 0.01) partners. In terms of sexual behaviour with male partners, few significant differences were found between homosexuals and bisexuals. A higher proportion of homosexuals engaged in receptive anal intercourse with casual partners (x2= 5.67, df = 1, p < 0.01). Two-factor analyses of variance examining the effects of the interaction between sexual identity and HIV serostatus on risk behaviour revealed that HIV seronegative heterosexuals reported the highest risk score on a composite measure of overall condom use (F (2, 141) = 4.411, p < 0.014) and on a composite measure of overall condom use with regular partners (F (2, 108) = 3.625, p < 0.030). Forward stepwise logistic regression disclosed three variables to be significantly associated with HIV seropositivity: greater age, number of known people with HIV/AIDS, and homosexuality. Stepwise regression analysis assessing risk behaviour through overall condom use showed that HIV positive status and education were associated with lower risk behaviour, accounting for 3% and 5% of the variance respectively. Having regular partners, and high income were associated with higher risk behaviour, accounting for 7% and for 4% of the variance respectively. Stepwise regression analysis examining risk behaviour through frequency of penetrative practices indicated that having regular partners was associated with sexual risk behaviour accounting for 15% of the variance. Total number of casual partners and low education level were also associated with high risk behaviour accounting for 18% and 2% of the variance respectively. Findings suggest the need to target prevention efforts at men having unsafe sex with male or female partners, regardless of sexual identity, and that type of partner in relationship plays an important role in sexual risk behaviour. Results also support the need for intervention programmes for HIV negative heterosexuals. The implications of the results for public health interventions to encourage HIV preventive behaviour in Brazil are discussed. Some future directions for research into the determinants of risk behaviour and some recommendations for the development of prevention programmes are proposed