Table 3
Prevalence and risk factors associated with Chlamydia trachomatis infection in the French population for subjects aged between 18 and 29 (NatChla study, Contexte de la Sexualité (CSF) survey)
| Men 18–29 years | Women 18–29 years | |||||||||||||||
| (p) | (p) | (p) | (p) | |||||||||||||
| Prevalence | Crude | Adjusted | Prevalence | Crude | Adjusted | |||||||||||
| N | n | %* | 95% CI | OR | 95% CI | OR† | 95% CI | N | n | %* | 95% CI | OR | 95% CI | OR† | 95% CI | |
| Total | 508 | 10 | 2.5 | 1.2 to 5.0 | 737 | 22 | 3.2 | 2.0 to 5.3 | ||||||||
| Age | (0.88) | (0.56) | ||||||||||||||
| 18–24 | 322 | 6 | 2.4 | 1.0 to 5.7 | 1 | 467 | 15 | 3.6 | 1.9 to 6.8 | 1 | ||||||
| 25–29 | 186 | 4 | 2.7 | 0.8 to 8.0 | 1.1 | 0.3 to 4.8 | 270 | 7 | 2.7 | 1.2 to 6.1 | 0.7 | 0.2 to 2.1 | ||||
| Education level | (0.51) | (0.01) | (0.01) | |||||||||||||
| High | 102 | 0 | 0.0 | - | 206 | 3 | 1.0 | 0.3 to 3.7 | 1 | 1 | ||||||
| Intermediate | 339 | 8 | 2.8 | 1.3 to 6.0 | 1 | 478 | 16 | 2.9 | 1.6 to 4.9 | 2.8 | 0.7 to 11.5 | 3.2 | 0.7 to 15.1 | |||
| Low | 65 | 2 | 3.4 | 0.7 to 15.3 | 1.2 | 40 | 3 | 12.5 | 4.1 to 32.4 | 13.5 | 2.3 to 79.3 | 16.5 | 2.4 to 112.1 | |||
| Region of residence | (0.01) | (0.02) | (0.40) | |||||||||||||
| Outside Paris area | 422 | 5 | 1.3 | 0.4 to 3.7 | 1 | 1 | 629 | 12 | 2.9 | 1.6 to 5.3 | 1 | |||||
| Paris area | 86 | 5 | 7.5 | 3.0 to 17.5 | 6.2 | 1.4 to 26.7 | 5.2 | 1.2 to 21.6 | 816 | 16 | 4.6 | 1.9 to 10.8 | 1.6 | 0.5 to 4.9 | ||
| Country of birth | (0.10) | (0.40) | ||||||||||||||
| France | 486 | 8 | 2.1 | 1.0 to 4.5 | 1 | 699 | 20 | 3.0 | 1.8 to 5.1 | 1 | ||||||
| Outside France | 22 | 2 | 8.5 | 1.6 to 34.3 | 4.4 | 0.7 to 29.2 | 38 | 2 | 6.0 | 1.2 to 24.6 | 2.0 | 0.4 to 11.4 | ||||
| Sexual orientation in past year | (0.45) | (<0.01) | (0.05) | |||||||||||||
| Only heterosexual partners | 444 | 8 | 2.6 | 1.2 to 5.4 | 1 | 679 | 17 | 2.6 | 1.5 to 4.5 | 1 | 1 | 1 | ||||
| Homo-bisexual partners§ | 33 | 2 | 4.9 | 1.1 to 18.8 | 1.9 | 0.4 to 10.4 | 46 | 4 | 13.0 | 4.1 to 34.6 | 5.6 | 1.4 to 22.7 | 2.8 | 1.0 to 7.5 | ||
| Number of sexual partners in past year | (0.01) | (0.19) | (0.01) | (0.03) | ||||||||||||
| 0–1 2 >2 | 333 67 87 | 3 3 4 | 0.8 6.3 7.0 | 0.2 to 3.3 1.8 to 19.4 2.4 to 18.8 | 1 7.9 8.9 | 1.2 to 51.8 1.5 to 52.6  ‡ | 1 2.4 | 0.6 to 9.1 | 538 121 70 | 13 3 6 | 2.4 1.5 13.1 | 1.2 to 4.5 0.5 to 4.8 5.3 to 28.7 | 1 0.6 6.1 | 0.1 to 2.4  ‡1.9 to 20.2 | 1 3.6 | 1.1 to 11.6 |
| New partner in the past year | (0.02) | (0.08) | ||||||||||||||
| 0 | 230 | 2 | 0.9 | 0.1 to 5.0 | 1 | 443 | 10 | 2.2 | 1.0 to 4.6 | 1 | ||||||
| ≥1 | 227 | 8 | 4.9 | 2.3 to 10.2 | 6.8 | 1.0 to 43.7 | 274 | 12 | 5.2 | 2.6 to 10.2 | 2.5 | 0.9 to 6.9 | ||||
| Last sexual partner | (0.01) | (0.03) | (<0.01) | (0.06) | ||||||||||||
| Cohabiting or principal partner | 333 | 3 | 0.8 | 0.2 to 3.4 | 1 | 1 | 596 | 11 | 2.0 | 1.0 to 4.2 | 1 | 1 | ||||
| Casual | 23 | 1 | 11.1 | 1.6 to 48.7 | 14.7 | 1.2 to 174.0 | 12.7 | 1.4 to 116.4 | 24 | 2 | 11.9 | 2.9 to 37.6 | 6.5 | 1.2 to 34.5 | 7.0 | 1.2 to 41.9 |
| New partner <3 months | 119 | 6 | 6.1 | 2.6 to 13.8 | 7.7 | 1.4 to 41.2 | 4.6 | 1.1 to 19.5 | 103 | 8 | 8.4 | 3.6 to 18.4 | 4.4 | 1.4 to 14.2 | 2.6 | 0.8 to 8.2 |
| Condom at last intercourse | (0.20) | (0.64) | ||||||||||||||
| Yes | 193 | 5 | 4.1 | 1.6 to 10.1 | 1 | 194 | 6 | 2.7 | 1.2 to 6.3 | 1 | ||||||
| No | 276 | 5 | 1.7 | 0.7 to 4.5 | 0.41 | 0.6 to 9.7 | 517 | 15 | 3.5 | 1.9 to 6.4 | 0.8 | 0.3 to 2.3 | ||||
↵* Prevalence weighted to take into account unequal selection probability and post-stratified for sex, age, level of education, marital status and region of residence.
↵† OR adjusted were presented for all variables included in logistic models, selected if p<0.25 and non-collinear in univariate analysis.
↵‡ Variable recoded in two classes, combining classes with similar prevalence.
↵§ Homo-bisexual partners: all four women infected with Chlamydia trachomatis were bisexual, one out of two men infected with Chlamydia trachomatis was bisexual.