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.