HOMOSEXUAL TRANSMISSION OF HIV AIDS IN ME XICO

Objective: To analyze HN homosexual transmission in Mexico, epidemic t rends and biological and social risk factors, Methods: This analysis i s based on 19 090 notifications of AIDS cases and on a review of two p revious studies that include 3 029 behavioral interviews (together wit h HIV serological screening tests) carried out at the Information Cent er of the Mexican Council for Control and Prevention of AIDS (CONASIDA ) (1988-89) and during a 1988 study in sis Mexican cities. Cities were included because they were the larger in the country and/or because t hey were touristic places(Mexico City, Guadalajara, Monterrey, Acapulc o, Tijuana and Merida). Logistic regressions were used to estimate the odds ratios for HIV seropositivity and for condom use. Results: Seven ty-two percent of the total reported AIDS cases (Ig 090) up to June 30 , 1994, were associated with male homosexual behaviors. In absolute nu mbers, cases under this category exhibited a rising trend until the en d of 1993. HN seroprevalence was 31% in 2 314 men with homosexual prac tices who attended ''FLORA'', the AIDS Information Center in Mexico, f rom January 1988 to June 30, 1989. The main predictive variables for s eropositivity were exclusive homosexual behavior, more than 40 life-ti me sexual partners, mixed sexual behavior (both insertive and receptiv e anal intercourse), sex with a person with AIDS, history of syphilis, and anal or genital warts. In general; these risk factors (data from the information Center) are similar to those found in the six Mexican cities study. There were significant differences in HN prevalence amon g the high-risk city samples (the highest in Mexico City with 25% and the lowest in Monterrey with 2.4%). Reported condom use was very low i n both studies: only 5% used a condom in all of their sexual relations hips. A statistically significant protective effect for HIV infection was found only for those who reported using a condom in all sexual enc ounters. In the six cities study, city of residence was a strong predi ctor of condom use. Conclusions: HIV homosexual transmission is steadi ly increasing; the recent decline in the percentage of homosexual case s is artificial because of the increment of cases under other categori es. Men who report exclusive homosexual behavior have higher prevalenc e rates of infection than bisexual men. Individuals with insertive/rec eptive behavior (mixed) have the highest risk for HN seropositivity, m ainly because of sociological, rather than biological reasons. This di fference in risks for HN and condom use may be related to the selectio n of sexual partners from specific social networks. Condom use was dem onstrated to be an effective method for preventing HN seropositivity a mong those who always use condoms. However it is alarming that only 5% of respondents reported condom use in all sexual encounters. Social a nd geographic differences in the cumulative numbers of cases, HIV prev alence, sexual practices and condom use must be taken into account in the planning of preventive programs.