Predictors of incident chlamydia infection (n=42) in 907 women who were chlamydia negative at baseline and provided repeat postal samples after 11–32 months
| Percentage of women with characteristic | Incidence of chlamydia % (proportion) of women | Relative risk (95% CI) | Adjusted relative risk* (95% CI) | ||
|---|---|---|---|---|---|
| Characteristic | With characteristic | Without characteristic | |||
| Age <20 years | 35.9 | 8.9 (29/326) | 2.2 (13/581) | 4.0 (2.1 to 7.5) | – |
| Black ethnicity | 17.5 | 5.7 (9/158) | 4.4 (33/747) | 1.3 (0.6 to 2.6) | 1.1 (0.5 to 2.2) |
| Smoker | 27.1 | 7.8 (19/245) | 3.5 (23/660) | 2.2 (1.2 to 4.0) | 2.2 (1.2 to 3.9) |
| New partner during 12 months follow-up | 48.0 | 8.0 (35/435) | 1.5 (7/471) | 5.4 (2.4 to 12.0) | 4.4 (2.0 to 9.9) |
| Condom use during 12 months follow-up† | 55.0 | 5.5 (27/487) | 3.8 (15/399) | 1.5 (0.8 to 2.7) | 1.2 (0.6 to 2.1) |
| Age at first sex <16 years | 29.3 | 6.8 (18/263) | 3.8 (24/636) | 1.8 (1.0 to 3.3) | 1.5 (0.8 to 2.7) |
| Neisseria gonorrhoeae‡ | 0.2 | 0 (0/2) | 4.7 (41/867) | – | – |
| Bacterial vaginosis‡ | 16.2 | 8.5 (12/141) | 3.7 (27/727) | 2.3 (1.2 to 4.4) | 2.0 (1.1 to 3.9) |
| Mycoplasma genitalium‡ | 2.9 | 12.0 (3/25) | 4.3 (36/837) | 2.8 (0.9 to 8.5) | 2.8 (2.3 to 9.0) |
| Carcinogenic HPV‡ | 16.4 | 8.5 (11/130) | 3.8 (25/663) | 2.2 (1.1 to 4.5) | 2.2 (1.1 to 4.3) |
*Adjusted for age <20 years.
†No data available on consistency of use.
‡At baseline.