Sociodemographic and Behavioral Characteristics at Baseline Visit From April 2006 to November 2010, we enrolled 1,744 Thai MSMinto the study, including 175 (10 %) who were eventually lost to follow-up. Of the remaining 1,569 participants, the median age was 26.0 years (range 18–56), and 805 (51 %)had secondary or vocational education. Most were either employed or studying (96 %), and identified themselves as homosexual, gay, or bisexual (96 %). Fifty-six percent of study participants reported engaging in unprotected anal intercourse, and 16 % in recreational drug use, and the median number of sexual partners reported was four (IQR 2, 9). A total of 312 participants were HIV infected (20 %) (Table 1).