San Francisco Young Men's Health Study, 1992-1999

The San Francisco Young Men's Health Study (SFYMHS) was a prospective epidemiological study, designed to learn more about the natural history of Acquired Immune Deficiency Syndrome (AIDS). The participants were from a sample of young men aged 18 to 29 who resided in 21 census tracts in San Francisco. These participants took part in a baseline survey in order to obtain information about behavior, attitudes, and beliefs relevant to AIDS. They were also asked to give a specimen of blood for serologic testing. This study had two major objectives: (1) to determine the general health status of young men living in San Francisco, and (2) to determine the degree to which this population was at risk for HIV infection. In addition, the study provided estimates of the prevalence of HIV infection among young gay and bisexual men. Five annual follow-up surveys were carried out in order to monitor the trends in these variables.
During Wave 2 of the Young Men's Health Study, the original participants were asked to complete a second interview and provide another blood specimen. In addition, these original participants were asked to volunteer the names of their gay and bisexual friends who might be interested in taking part in the study. This secondary group, recruited between May 1993 and January 1994, is referred to as the Referral or Snowball sample. This group was also asked to participate in an interview and provide a blood sample. Beginning with Wave 3 of the main Original sample, the Referral sample was re-interviewed together with the Original sample. Wave 3 of the Original sample is combined with Wave 2 of the Referral sample, Wave 4 of the Original sample was combined with Wave 3 of the Referral sample, and so on until Wave 6 of the Original sample, which was combined with Wave 5 of the Referral sample.
Beginning with Wave 4 of the Original sample, the Host Genetics Sub-Study was started. Wave 1 of this sub-study shows the results for 91 members of the SFYMHS who were selected to be part of the Host Genetics Sub-Study. Some 38 gay or bisexual men from the Original Random sample participated, and 53 gay or bisexual men from the Referral sample were also chosen. All were interviewed in person between June 1995 and May 1996. There were three additional waves of the Host Genetics Sub-Study. Wave 1 of this sub-study corresponds to Wave 4 of the Original sample, Wave 2 corresponds to Wave 5 of the Original sample, and Wave 3 corresponds to Wave 6 of the Original sample. Wave 4 of the Host Genetics Sub-Study included the results for 64 members of the Original Sample who still participated in the Host Genetics Sub-Study. Some 30 gay or bisexual men from the Original Random Sample participated, and 34 gay or bisexual men from the Referral sample participated. All were interviewed for the last time between January 1999 and October 1999.