TABLE 1

Comparison of Participant Characteristics Across All 4 Study Waves, Unadjusted and Adjusted for Propensity Score

CharacteristicWave 1, N = 371Wave 2, N = 409Wave 3, N = 400Wave 4, N = 400P,a UnadjustedP,a Propensity Score Adjusted
N (%)Mean (SD)N (%)Mean (SD)N (%)Mean (SD)N (%)Mean (SD)
Enrollment site
 Teen Health Center239 (64.4)268 (65.5)250 (62.5)307 (76.8)<.0001.55
 Health department132 (35.6)141 (34.5)150 (37.5)93 (23.3)
Demographic characteristics and medical history
 Age, y18.7 (3.0)18.8 (2.9)19.1 (2.8)19.1 (2.6).18.5
 Race and/or ethnicity
  White or Asian American110 (30.1)114 (27.9)108 (27.0)91 (22.8).13.78
  African American or multiracial255 (69.9)295 (72.1)292 (73.0)309 (77.3)
 Appalachian descent24 (6.7)16 (3.9)9 (2.3)6 (1.5).0006.22
 Hispanic ethnicity25 (6.9)24 (5.9)28 (7.0)21 (5.3).69.53
 Health insurance plan
  Private32 (8.6)63 (15.4)35 (8.8)52 (13)˂.0001.69
  Medicaid196 (52.8)217 (53.1)269 (67.3)284 (71)
  None or not sure143 (38.5)129 (31.5)96 (24.0)64 (16)
 History of any STI170 (46.5)212 (52.0)202 (50.5)215 (53.8).22.29
Behaviors
 Age of first sexual intercourse ≤13 y of age76 (21.5)85 (20.8)63 (15.8)44 (11.1).0014.07
 No. male sexual partners in lifetime ≥2282 (80.6)354 (87.8)327 (82.2)311 (78.7).02.29
 No. male sexual partners in the past 3 mo ≥271 (20.1)86 (21.0)77 (19.3)68 (17.4).48.15
 Main sexual partner male319 (89.1)380 (92.9)361 (90.3)314 (79.3)˂.0001.97
 Ever had anal sex with a male partner89 (25.3)93 (22.7)81 (20.3)83 (21.3).39.50
 Condom use with main partner in the past 3 mo
  Less than every time298 (80.3)333 (81.4)342 (85.5)353 (88.3).01.45
  Every time73 (19.7)76 (18.6)58 (14.5)47 (11.8)
 Condom use at last sexual intercourse121 (37.5)146 (38.5)139 (34.8)105 (26.3).02.42
 Smoked at least 100 cigarettes in lifetime114 (31.8)117 (29.1)86 (21.9)67 (16.9)˂.0001.58
  • —, not applicable.

  • a P value calculated by using χ2 test, Fisher’s exact test, Kruskal-Wallis test, or analysis of variance.