Risk factors for incident chlamydia infections*
| Univariate analysis‡ | ||||||
|---|---|---|---|---|---|---|
| No† | Obs | Py | Rate | RR | p Value | |
| *Included in analysis are those people with at least two chlamydia tests during the study period, and who are considered to have been uninfected with chlamydia during the study period. | ||||||
| †No = the number of people (sums to 978 for all variables except “gonorrhoea” and “syphilis” for which subjects can contribute to more that one level); Obs = number of incident infections; Py = person years of follow up; rate = incident rate per 100 person years. | ||||||
| ‡In univariate analysis each variable is fitted separately. p Values in parentheses are overall test for heterogeneity. | ||||||
| §Prevalent infection is at first test during study period. Incident infections are up to 7 days before date of relevant incident chlamydia infection during study period. Levels are hierarchical: “no test,” “no,” “prevalent,” “incident” (a person contributes only to relevant levels). | ||||||
| ¶Prevalent chlamydia infection is at time of first chlamydia test during study period. | ||||||
| Sex | ||||||
| Male | 454 | 89 | 680.1 | 13.1 | 1.0 | |
| Female | 524 | 151 | 841.7 | 17.9 | 1.36 | 0.040 |
| Age (years) at first incident chlamydia | ||||||
| 30+ | 231 | 29 | 357.9 | 8.1 | 1.0 | |
| 25–29 | 200 | 50 | 308.8 | 16.2 | 2.06 | 0.004 |
| 20–24 | 226 | 73 | 344.4 | 21.2 | 2.76 | <0.001 |
| 15–19 | 206 | 79 | 320.4 | 24.7 | 3.16 | <0.001 |
| 12–14 | 115 | 9 | 190.4 | 4.7 | 0.57 | 0.159 (<0.001) |
| Time | ||||||
| <June 1997 | 950 | 135 | 837.8 | 16.1 | 1.0 | |
| ≥June 1997 | 846 | 105 | 684 | 15.4 | 0.95 | 0.707 |
| Resident status | ||||||
| Permanent | 898 | 217 | 1426.9 | 15.2 | 1.0 | |
| Removed | 80 | 23 | 94.9 | 24.2 | 1.65 | 0.047 |
| Marital status | ||||||
| Never married | 289 | 54 | 463.0 | 11.7 | 1.0 | |
| 1+ wives | 587 | 159 | 908.7 | 17.5 | 1.55 | 0.011 |
| Widow/past | 70 | 23 | 107.1 | 21.5 | 1.77 | 0.048 |
| Not known | 32 | 4 | 43.0 | 9.3 | 0.80 | 0.689 (0.038) |
| Alcohol | ||||||
| No abuse | 583 | 146 | 954.7 | 15.3 | 1.0 | |
| Abuse | 347 | 88 | 499.0 | 17.6 | 1.18 | 0.282 |
| Not known | 48 | 6 | 68.1 | 8.8 | 0.57 | 0.211 (0.210) |
| Petrol sniffing | ||||||
| Never | 785 | 173 | 1216.0 | 14.2 | 1.0 | |
| Male ever occasional | 34 | 10 | 54.3 | 18.4 | 2.30 | <0.001 |
| Male ever regular | 107 | 25 | 163.3 | 15.3 | 1.25 | 0.269 |
| Female ever occasional | 26 | 21 | 43.7 | 48.6 | 3.62 | <0.001 |
| Female ever regular | 26 | 11 | 44.5 | 24.7 | 1.79 | 0.110 (0.001) |
| Gonorrhoea§ in study period | ||||||
| No | 815 | 131 | 1130.4 | 11.6 | 1.0 | |
| Prevalent | 148 | 50 | 171.8 | 29.1 | 2.53 | <0.001 |
| Incident | 219 | 51 | 197.5 | 25.8 | 2.01 | <0.001 |
| No test | 66 | 8 | 22.0 | 36.3 | 3.39 | 0.001 (<0.001) |
| Syphilis§ in study period | ||||||
| No | 894 | 199 | 1311.9 | 15.2 | 1.0 | |
| Prevalent | 23 | 5 | 28.3 | 17.7 | 1.27 | 0.489 |
| Incident | 15 | 9 | 14.7 | 61.3 | 3.87 | 0.003 |
| No test | 200 | 27 | 166.9 | 16.2 | 1.15 | 0.498 (0.023) |
| Syphilis in 91–95 | ||||||
| No | 689 | 147 | 1106.5 | 13.3 | 1.0 | |
| Prevalent infection | 105 | 36 | 153.7 | 23.4 | 1.85 | 0.004 |
| Incident infection | 93 | 45 | 139.0 | 32.8 | 2.48 | <0.001 |
| No test | 91 | 12 | 122.7 | 9.8 | 0.75 | 0.357 (<0.001) |
| Prevalent¶ chlamydia | ||||||
| No | 877 | 199 | 1384.2 | 14.4 | 1.0 | |
| Yes | 101 | 41 | 137.6 | 29.8 | 2.22 | <0.001 |