Table 1. Demographic and behavioral characteristics at baseline of North American men who have sex with men from four longitudinal cohort studies, 1995–2007.
| Characteristic at baseline | VPS N (%) | Vax004 N(%) | Explore N(%) | STEP N(%) | Total N (%) |
| Total number of participants included | 2974 | 4456 | 3798 | 1049 | 12,277 |
| Median age (IQR) | 32 (27–38) | 36 (30–43) | 33 (28–39) | 34 (27–40) | 34 (28–40) |
| Race | |||||
| White | 2259 (76.0%) | 3827 (85.9%) | 2800 (73.7%) | 754 (71.9%) | 9640 (78.5%) |
| Black | 183 (6.2%) | 162 (3.6%) | 241 (6.4%) | 94 (9.0%) | 680 (5.5%) |
| Hispanic | 370 (12.4%) | 295 (6.6%) | 543 (14.3%) | 133 (12.7%) | 1341 (10.9%) |
| Asian | 92 (3.1%) | 71 (1.6%) | 99 (2.6%) | 32 (3.1%) | 294 (2.4%) |
| Other | 70 (2.4%) | 101 (2.3%) | 115 (3.0%) | 36 (3.4%) | 322 (2.6%) |
| Number of Partner in last 6 months | |||||
| 0 | 0 (0.0%) | 128 (2.8%) | 83 (2.2%) | 55 (5.2%) | 266 (2.2%) |
| 1 | 674 (22.7%) | 986 (22.1%) | 454 (12.0%) | 226 (21.5%) | 2340 (19.1%) |
| 2–5 | 1117 (37.6%) | 1669 (37.4%) | 1273 (33.5%) | 387 (36.9%) | 4446 (36.2%) |
| 6–10 | 535 (18.0%) | 761 (17.1%) | 791 (20.8%) | 167 (15.9%) | 2254 (18.4%) |
| >10 | 648 (21.8%) | 912 (20.5%) | 1197 (31.5%) | 214 (20.4%) | 2971 (24.2%) |
| Any methamphetamine use in thelast six months | 272 (9.15%) | 371 (8.3%) | 479 (12.6%) | 62 (5.9%) | 1184 (9.6%) |
| Any popper use in the last six months | 821 (27.6%) | 1276 (28.6%) | 1292 (34.0%) | 172 (16.4%) | 3561 (29.0%) |