Published odds ratios associated with factors used in first sample size calculation
| Factor | Observed prevalence (%) | OR | Reference | |
|---|---|---|---|---|
| Patient | Control | |||
| Genital chlamydial infection | 40 | 4 | 10 | Bevan et al12, Grun et al13 |
| Smoker (current) | 43 | 23 | 2 | Scholes et al5 |
| Gonorrhoea | 15 | 5 | 3 | Scholes et al5 |
| 1 lifetime partner | 12 | 29 | 0.5 | Scholes et al5 |
| 2–4 lifetime partners | 42 | 33 | 1.6 | Scholes et al5 |
| Age at first sexual intercourse <18 years | 68 | 31 | 2.8 | Scholes et al5 |