Table 5.
Age of Initiation of Anal Sex with a Man by Birth Cohort of MSM Participants in the American Men’s Internet Survey, United States, 2015
| Birth Cohort | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| All | 1950–1969 | 1970–1979 | 1980–1989 | 1990–2000 | ||||||
| (N=8,331) | (N=2,164) | (N=1,085) | (N=2,038) | (N=3,044) | ||||||
| Had oral sex by age xa | No. | (%) | No. | (%) | No. | (%) | No. | (%) | No. | (%) |
| 10 | 31 | (0.4) | 10 | (0.5) | 6 | (0.6) | 9 | (0.4) | 6 | (0.2) |
| 11 | 78 | (0.9) | 29 | (1.3) | 11 | (1.0) | 22 | (1.1) | 16 | (0.5) |
| 12 | 243 | (2.9) | 89 | (4.1) | 44 | (4.1) | 53 | (2.6) | 57 | (1.9) |
| 13 | 470 | (5.6) | 161 | (7.4) | 68 | (6.3) | 104 | (5.1) | 137 | (4.5) |
| 14 | 800 | (9.6) | 232 | (10.7) | 107 | (9.9) | 180 | (8.8) | 281 | (9.2) |
| 15 | 1286 | (15.4) | 333 | (15.4) | 159 | (14.7) | 297 | (14.6) | 497 | (16.3) |
| 16 | 1981 | (23.8) | 457 | (21.1) | 213 | (19.6) | 451 | (22.1) | 860 | (28.3) |
| 17 | 2677 | (32.1) | 586 | (27.1) | 257 | (23.7) | 620 | (30.4) | 1214 | (39.9) |
| 18 | 3843 | (46.1) | 785 | (36.3) | 371 | (34.2) | 941 | (46.2) | 1746 | (57.4) |
| 19 | 4655 | (55.9) | 902 | (41.7) | 468 | (43.1) | 1145 | (56.2) | 2140 | (70.3) |
| 20 | 5235 | (62.8) | 1021 | (47.2) | 542 | (50.0) | 1301 | (63.8) | 2371 | (77.9) |
| 21 | 5826 | (69.9) | 1148 | (53.0) | 640 | (59.0) | 1471 | (72.2) | 2567 | (84.3) |
| 22 | 6210 | (74.5) | 1251 | (57.8) | 704 | (64.9) | 1588 | (77.9) | 2667 | (87.6) |
| 23 | 6474 | (77.7) | 1320 | (61.0) | 758 | (69.9) | 1683 | (82.6) | 2713 | (89.1) |
| 24 | 6710 | (80.5) | 1375 | (63.5) | 810 | (74.7) | 1770 | (86.8) | 2755 | (90.5) |
| 25 | 6927 | (83.1) | 1472 | (68.0) | 854 | (78.7) | 1837 | (90.1) | 2764 | (90.8) |
| Log-rank p-valueb | <0.001 | <0. 001 | <0.001 | ref | ||||||
| Mean (SD) age of first anal sex | 20.3 [6.7] | 24.0 [10.1] | 21.5 [6.3] | 19.4 [4.04] | 17.8 [2.6] | |||||
| Rank-sum p-valuec | <0.001 | <0.001 | <0.001 | ref | ||||||
a
Number and percentages are cumulative. For example by 18 years of age, 3,843 (46.1%) participants ever had anal sex with a male partner.
b
Log-rank p-value comparing equality of survival until first anal sex of one birth cohort to referent group of those MSM born 1990–2000.
c
Rank-sum p-value by Wilcoxon two-sample test comparing mean age of first anal sex of one birth cohort to referent group of those MSM born 1990–2000.