Trends in sexual behaviour in a cohort of homosexual men: a 7 year prospective study.

A cohort of homosexual men at risk for human immunodeficiency virus (HIV) infection were studied prospectively over a 7-year period (1982/88) to assess trends in sexual behaviour and amyl nitrite intake. During the period, there were dramatic declines in the proportion of HIV seropositive and seronegative subjects reporting multiple casual partners for anal intercourse, unprotected anal intercourse and recreational use of amyl nitrite. Reported rates of orogenital intercourse remained the same during the period, whilst the total number of seroconversions fell from 17 for the period 1982-84 to 8 for 1985-88. High-risk sexual and related social behaviour among homosexual men, as assessed by patterns of anal intercourse behaviour and nitrite intake, changed over the 7-year period, with the greatest changes apparent before the widespread availability of HIV antibody testing and public education campaigns. This highlights the effectiveness of peer-group and community-based programmes in modifying the sexual behaviour of their members.