Table 2.
Demographic Characteristics, Syphilis Prevalence, and Risk Factors for Men Who Have Sex With Men in 61 Cities in China
| Characteristics | Subjects, No. (%) | Syphilis Cases, No. (%) | Prevalence (CI)a | Unadjusted ORb (CI) | Adjusted OR (CI) | Adjusted P Valueb,c |
|---|---|---|---|---|---|---|
| Demographics | ||||||
| Age, y | ||||||
| 18–24 | 20 454 (43.3) | 1686 (30.4) | 8.2 (7.9–8.6) | 1.0 | 1.0 | |
| 25–29 | 9377 (19.9) | 1121 (20.2) | 12.0 (11.3–12.6) | 1.5 (1.4–1.6) | 1.5 (1.4–1.7) | <.0001 |
| 30–34 | 6574 (13.9) | 826 (14.9) | 12.6 (11.8–13.4) | 1.6 (1.4–1.7) | 1.7 (1.5–1.9) | <.0001 |
| 35–39 | 4419 (9.4) | 658 (11.9) | 14.9 (13.8–15.9) | 1.9 (1.7–2.1) | 2.0 (1.7–2.2) | <.0001 |
| 40–49 | 4654 (9.9) | 935 (16.8) | 20.1 (18.9–21.2) | 2.7 (2.4–2.9) | 2.8 (2.5–3.2) | <.0001 |
| 50–69 | 1182 (2.5) | 274 (4.9) | 23.2 (20.8–25.6) | 3.1 (2.7–3.6) | 3.2 (2.7–3.8) | <.0001 |
| Refused/missing | 571 (1.2) | 52 (0.94) | … | … | … | … |
| Marital status | ||||||
| Never married | 34 784 (73.6) | 3617 (65.1) | 10.4 (10.1–10.7) | 1.0 | 1.0 | |
| Married | 9592 (20.3) | 1452 (26.2) | 15.1 (14.4–15.9) | 1.5 (1.4–1.6) | .86 (.78–.96) | .0047 |
| Live with a partner (male/female) | 645 (1.4) | 72 (1.3) | 11.2 (8.7–13.6) | 1.2 (.96–1.6) | .98 (.75–1.3) | .9062 |
| Divorced/widowed | 2200 (4.7) | 410 (7.4) | 18.6 (17.0–20.3) | 2.0 (1.8–2.3) | .95 (.83–1.1) | .4967 |
| Refused/missing | 10 (0.02) | 1 (0.02) | … | … | … | … |
| Ethnicity | ||||||
| Han Chinese | 43 635 (92.4) | 5124 (92.3) | 11.7 (11.4–12.0) | 1.0 | 1.0 | |
| Other | 355 (7.5) | 426 (7.7) | 12.0 (10.9–13.1) | 1.2 (1.1–1.3) | 1.2 (1.0–1.3) | .0076 |
| Refused/missing | 42 (0.09) | 2 (0.04) | … | … | … | … |
| Highest education | ||||||
| Junior high | 9959 (21.1) | 1479 (26.6) | 14.9 (14.2–15.5) | 1.0 | 1.0 | |
| Senior high | 16 666 (35.2) | 2181 (39.3) | 13.1 (12.6–13.6) | .84 (.78–.90) | .97 (.90–1.1) | .4579 |
| College or above | 20 592 (43.6) | 1891 (34.1) | 9.2 (8.8–9.6) | .55 (.51–.59) | .70 (.64–.77) | <.0001 |
| Refused/missing | 14 (0.03) | 1 (0.02) | … | … | … | … |
| Household registration | ||||||
| Local resident | 26 607 (56.3) | 2921 (52.6) | 11.0 (10.6–11.4) | 1.0 | 1.0 | |
| Non–local resident | 20 601 (43.6) | 2626 (47.3) | 12.7 (12.3–13.2) | 1.1 (1.05–1.2) | 1.2 (1.1–1.3) | <.0001 |
| Refused/missing | 23 (0.05) | 5 (0.09) | … | … | … | … |
| Sexual behavior in the past 6 mo | ||||||
| Venues for finding sex partners | ||||||
| Bars/tea houses/dance halls | 10 380 (22.0) | 1186 (21.4) | 11.4 (10.8–12.0) | 1.0 | 1.0 | |
| Public bathhouses/saunas | 6436 (13.6) | 1197 (21.6) | 18.6 (17.6–19.5) | 1.7 (1.5–1.8) | 1.4 (1.3–1.5) | <.0001 |
| Parks | 5461 (11.6) | 751 (13.5) | 13.8 (12.9–14.7) | 1.4 (1.3–1.6) | 1.2 (1.1–1.3) | .0024 |
| Internet sites | 21 444 (45.4) | 2033 (36.6) | 9.5 (9.1–9.9) | .85 (.78–.91) | .97 (.89–1.1) | .4801 |
| Other | 2681 (5.7) | 312 (5.6) | 11.6 (10.4–12.9) | 1.0 (.88–1.1) | 1.0 (.90–1.2) | .6048 |
| Refused/missing | 829 (1.7) | 73 (1.3) | … | … | … | … |
| Buy male sex | ||||||
| No | 44 541 (94.3) | 5209 (93.8) | 11.7 (11.4–12.0) | 1.0 | 1.0 | |
| Yes | 2543 (5.4) | 328 (5.9) | 12.9 (11.6–14.2) | .85 (.75–.96) | .94 (.82–1.1) | .3613 |
| Refused/missing | 147 (0.31) | 15 (0.27) | … | … | ||
| Sell sex to a male | ||||||
| No | 42 732 (90.5) | 4991 (89.9) | 11.7 (11.4–12.0) | 1.0 | 1.0 | |
| Yes | 4358 (9.2) | 553 (10.0) | 12.7 (11.7–13.7) | .91 (.83–1.0) | .96 (.89–1.1) | .5458 |
| Refused/missing | 141 (0.30) | 8 (0.14) | … | … | ||
| No. of male sex partners | ||||||
| 0 | 5886 (12.5) | 545 (9.8) | 9.3 (8.5–10.0) | 1.0 | 1.0 | |
| 1 | 13 421 (28.4) | 1279 (23.0) | 9.5 (9.0–10.0) | 1.0 (.92–1.1) | 1.1 (1.0–1.3) | .0267 |
| 2–10 | 22 370 (47.4) | 2958 (53.3) | 13.2 (12.8–13.7) | 1.4 (1.3–1.6) | 1.5 (1.3–1.7) | <.0001 |
| >10 | 2372 (5.0) | 368 (6.6) | 15.5 (14.1–17.0) | 1.7 (1.5–1.9) | 1.7 (1.4–1.9) | <.0001 |
| Refused/missing | 3182 (6.7) | 402 (7.2) | … | … | … | … |
| Consistent condom use with male partners | ||||||
| No | 24 107 (51.0) | 3085 (55.6) | 12.8 (12.4–13.2) | 1.0 | 1.0 | |
| Yes | 16 720 (35.4) | 1862 (33.5) | 11.1 (10.7–11.6) | .81 (.76–.86) | .71 (.64–.79) | <.0001 |
| No sex in past 6 mo | 5886 (12.5) | 545 (9.8) | 9.3 (8.5–10.0) | .69 (.63–.76) | .65 (.55–.76) | <.0001 |
| Refused/missing | 518 (1.1) | 60 (1.0) | … | … | … | … |
| No. of female sex partners | ||||||
| 0 | 35 495 (75.2) | 4196 (75.6) | 11.8 (11.5–12.2) | 1.0 | 1.0 | |
| 1 | 8401 (17.8) | 1040 (18.7) | 12.4 (11.7–13.1) | 1.0 (.96–1.1) | .86 (.75–.98) | <.0001 |
| ≥2 | 2699 (5.7) | 261 (4.7) | 9.7 (8.6–10.8) | .81 (.71–.93) | .67 (.54–.84) | <.0001 |
| Refused/missing | 636 (1.3) | 55 (1.0) | … | … | … | … |
| Study design | ||||||
| Sampling method | ||||||
| Snowball | 43 437 (92.0) | 5024 (90.5) | 11.6 (11.3–11.9) | 1.0 | 1.0 | |
| RDS | 3794 (8.0) | 528 (9.5) | 13.9 (12.8–15.0) | 1.4 (1.2–1.6) | 1.4 (1.2–1.5) | <.0001 |
| City-level characteristics | ||||||
| Administrative level | ||||||
| Directly under central government | 6051 (12.8) | 776 (14.0) | 12.8 (12.0–13.7) | 1.6 (.90–2.9) | 1.5 (.87–2.6) | .1384 |
| Province capitals | 23 422 (49.6) | 2913 (52.5) | 12.4 (12.0–12.9) | 1.5 (1.1–2.0) | 1.4 (1.04–1.8) | .0257 |
| Other cities | 17 758 (37.6) | 1863 (33.6) | 10.5 (10.0–10.9) | 1.0 | 1.0 | |
| Overall | 47 231 (100) | 5552 (100) | 11.8 (11.5–12.0) | … | … | … |
Abbreviations: CI, confidence interval; OR, odds ratio; RDS, respondent-driven sampling.
a CIs are 95% CIs in all cases and were calculated by approximating the binomial distribution with a normal distribution.
b ORs and P values were calculated by using a multilevel logistic regression model.
c P values are 2-sided in all cases.