Table 3:
Bivariate and multivariate analysis of risk factors for incident HIV infection
| Incident HIV (cases/person-years) |
Crude HIV incidence (95% CI) |
Bivariate analysis hazard ratio (95% CI) |
Multivariate analysis hazard ratio (95% CI) |
|||
|---|---|---|---|---|---|---|
| Total | 212/3554 | 6·0 (5·2–6·8) | ·· | |||
| Age group (years) | ||||||
| 18–21 | 49/537 | 9·1 (6·8–12·1) | 2·5 (1·6–3·7) | 2·5 (1·7–3·9) | ||
| 22–29 | 122/1917 | 6·4 (5·3–7·6) | 1·7 (1·2–2·5) | 1·68 (1·2–2·4) | ||
| ≥30 | 41/1100 | 3·7 (2·7–5·0) | 1 (ref) | 1 (ref) | ||
| Education | ||||||
| Primary | 3/46 | 6·5 (1·3–19·1) | 1·4 (0·4–4·4) | ·· | ||
| Secondary or vocational | 122/1668 | 7·3 (6·1–8·7) | 1·5 (1·2–2·0) | ·· | ||
| University and above | 87/1841 | 4·7 (3·8–5·8) | 1 (ref) | ·· | ||
| Study or work status | ||||||
| Work | 101/2120 | 4·7 (3·9–5·8) | 1 (ref) | ·· | ||
| Work and study | 100/1304 | 7·7 (6·2–9·3) | 1·6 (1·2–2·1) | ·· | ||
| Neither | 11/130 | 8·4 (4·2–15·1) | 1·8 (1·0–3·3) | ·· | ||
| Current living situation | ||||||
| With family | 69/1504 | 4·6 (3·6–5·8) | 1 (ref) | 1 (ref) | ||
| With partner | 28/502 | 5·6 (3·7–8·1) | 1·2 (0·8–1·9) | 1·2 (0·8–1·9) | ||
| Alone or with housemate | 115/1547 | 7·4 (6·1–8·9) | 1·6 (1·2–2·2) | 1·5 (1·1–2·1) | ||
| Ever used methamphetamine to increase sexual pleasure | ||||||
| Yes | 28/197 | 14·2 (9·4–20·5) | 2·7 (1·8–4·0) | 2·0 (1·2–3·1) | ||
| No | 184/3357 | 5·5 (4·7–6·3) | 1 (ref) | 1 (ref) | ||
| Use of erectile dysfunction drugs in past 4 months | ||||||
| Yes | 29/267 | 10·9 (7·3–15·6) | 1·9 (1·3–2·9) | ·· | ||
| No | 183/3288 | 5·6 (4·8–6·4) | 1 (ref) | ·· | ||
| Anal sex in past 4 months | ||||||
| Yes | 208/3278 | 6·3 (5·5–7·3) | 4·4 (1·6–11·8) | 3·6 (1·3–9·9) | ||
| No | 4/276 | 1·5 (0·4–3·7) | 1 (ref) | 1 (ref) | ||
| Total number of male partners in past 4 months | ||||||
| 0 | 3/245 | 1·2 (0·2–3·6) | 1 (ref) | ·· | ||
| 1–5 | 135/2370 | 5·7 (4·8–6·7) | 4·7 (1·5–14·7) | ·· | ||
| ≥6 | 74/939 | 7·9 (6·2–9·9) | 6·5 (2·0–20·6) | ·· | ||
| Condom use with male partner in past 4 months* | ||||||
| Always | 96/1966 | 4·9 (4·0–5·0) | 1 (ref) | ·· | ||
| Not always | 112/1312 | 8·5 (7·0–10·3) | 1·8 (1·3–2·3) | ·· | ||
| Presence of circumcision at baseline | ||||||
| Yes | 18/411 | 4·4 (2·6–6·9) | 1 (ref) | ·· | ||
| No | 194/3143 | 6·2 (5·3–6·9) | 1·4 (0·9–2·3) | ·· | ||
| Ever had group sex | ||||||
| Yes | 53/536 | 9·9 (7·4–12·9) | 1·9 (1·4–2·6) | ·· | ||
| No | 159/3019 | 5·3 (4·5–6·2) | 1 (ref) | ·· | ||
| Ever coerced into sex | ||||||
| Yes | 46/581 | 7·9 (5·8–10·6) | 1·4 (1·0–2·0) | ·· | ||
| No | 166/2971 | 5·6 (4·8–6·5) | 1 (ref) | ·· | ||
| Paid money for sex in past 4 months | ||||||
| Yes | 18/386 | 4·7 (2·8–7·4) | 1 (ref) | ·· | ||
| No | 194/3169 | 6·1 (5·3–7·0) | 1·3 (0·8–2·1) | ·· | ||
| Received money for sex in past 4 months | ||||||
| Yes | 22/301 | 7·3 (4·6–11·1) | 1·2 (0·8–1·9) | ·· | ||
| No | 190/3169 | 5·8 (5·0–6·6) | 1 (ref) | ·· | ||
| Finding casual sex partners on the internet in past 4 months | ||||||
| Yes | 38/381 | 10·0 (7·0–13·7) | 2·0 (1·4–2·9) | 1·6 (1·0–2·6) | ||
| No | 174/3173 | 5·5 (4·7–6·7) | 1 (ref) | 1 (ref) | ||
| Ever attended chemsex party* | ||||||
| Yes | 13/49 | 26·8 (14·3–45·8) | 5·3 (2·9–9·7) | 2·9 (1·4–5·7) | ||
| No | 67/1317 | 5·1 (3·9–6·5) | 1 (ref) | 1 (ref) | ||
| Any ulcerative STIs at baseline | ||||||
| Yes | 154/2171 | 7·1 (6·0–8·3) | 1·7 (1·3–2·3) | 1·7 (1·3–2·3) | ||
| No | 58/1384 | 4·2 (3·2–5·4) | 1 (ref) | 1 (ref) | ||
Only significant variables are reported for the multivariate analysis. STI=sexually transmitted infection.
*
Missing values for this factor were handled by an indicator variable.