Time trends of HIV-I antibody prevalence in homosexual men.

1840 homosexual and bisexual men were tested for human immunodeficiency virus type I (HIV) infection at the Landesinstitut für Tropenmedizin, Berlin between April 1983 and December 1987. A total of 25.1% were seropositive for HIV, but the percentage was seemingly declining. During the study period we observed also a steady decrease in the prevalence of lymphadenopathy syndrome (LAS), antibodies to hepatitis B and syphilis, and high-risk sexual behaviour in the study population. By adjusting for these changes of population characteristics we assessed the odds of HIV infection which had more than doubled between 1983 and 1986 (prevalence odds ratio 2.43, 95% confidence interval 1.58 to 3.76). In 1987 the HIV prevalence odds showed a drop which, however, was not significant (p = 0.34) when compared with the odds in 1986. Methodological aspects of time trend estimation based on data of voluntary HIV testing are discussed.