Frequency and risk factors for incident and redetectedChlamydia trachomatisinfection in sexually active, young, multi-ethnic women: a community based cohort study

Abstract

ObjectiveTo investigate the frequency and risk factors for incident and redetected Chlamydia trachomatis infection in sexually active, young, multi-ethnic women in the community.DesignCohort study.Setting20 London universities and Further Education colleges.Participants954 sexually experienced women, mean age 21.5 years (range 16–27), 26% from ethnic minorities, who were recruited to the Prevention of Pelvic Infection (POPI) chlamydia screening trial between 2004 and 2006, and returned repeat postal self-taken vaginal swabs 11–32 (median 16) months after recruitment.ResultsThe estimated annual incidence of chlamydia infection among 907 women who tested negative at baseline was 3.4 per 100 person-years (95% CI 2.5 to 4.6 per 100 person-years), but 6.6 per 100 person-years (95% CI 4.5 to 9.3 per 100 person-years) in the 326 teenagers (<20 years). Predictors of incident chlamydia infection were age <20 years (relative risk (RR) 4.0, 95% CI 2.1 to 7.5), and (after adjusting for age) a new sexual partner during 12 months follow-up (RR 4.4, 95% CI 2.0 to 9.9), smoking (RR 2.2 95% CI 1.2 to 3.9), concurrent bacterial vaginosis (RR 2.0 95% CI 1.1 to 3.9) and high risk carcinogenic human papillomavirus (RR 2.2, 95% CI 1.1 to 4.3). Of 47 women positive for chlamydia at baseline, 12 (25.5%, 95% CI 13.9% to 40.3%) had redetected infection at a median of 16 months follow-up. Taking into account follow-up time (65 person-years), the annual redetection rate was 18.5 per 100 person-years (95% CI 9.9 to 30.0 per 100 person-years).ConclusionsOne in four women with chlamydia infection at baseline retested positive, supporting recent recommendations to routinely retest chlamydia positives.

Risk Factors for Incident and Redetected Chlamydia trachomatis Infection in Women

“…Another potential explanation is that women with lower socioeconomic status may be less likely to participate in CT screening. 31 In line with Aghaizu et al 7 and Hwang et al, 11 we found that women with a high-risk HPV infection at baseline were at increased risk for incident CT infection. In our study, this association remained after controlling for number of sexual partners and condom use, indicating that the increased risk of CT infection was not explained by more risk-taking sexual behavior among the HPV-positive women.…”

“…Based on previous studies, 7,[9][10][11]13,20 we a priori hypothesized that the risk for incident or redetected CT infection may be affected by the woman's age, educational level, age at sexual debut, number of sexual partners during follow-up, condom use, oral contraceptive use, smoking, and high-risk HPV status. In the main analysis, all potential risk factors were measured at baseline, except for "number of sexual partners during follow-up," which was measured at follow-up.…”

“…Results were presented as odds ratios (ORs) with corresponding 95% confidence intervals (CIs). The analyses were initially adjusted for age as a potential confounder because young age is an established risk factor for CT infection 7,8,10,19 and is potentially associated with the other risk factors considered. In multivariate analyses, all potential risk factors were included (age, educational level, age at sexual debut, number of sexual partners during follow-up, current condom use, current oral contraceptive use, current smoking, and high-risk HPV status).…”

“…7,11 Conversely, in the few available studies, no associations have been observed between HPV infection and CT persistence 20 or recurrence. 7 In the present study, we investigated risk factors for incident and redetected CT infection, including the role of highrisk HPV, in a population-based cohort of nearly 8000 young Danish women.…”

“…6 Several prospective studies have investigated risk factors for incident, 7-11 recurrent, 7,8,10,[12][13][14][15][16][17][18][19] or persistent 20,21 CT infection in women. However, several studies suffered from substantial loss to follow-up 7,10,13,15,17 or small sample sizes resulting in low statistical power, especially in analysis of recurrent 7,8 or persistent CT infection. 20,21 Moreover, several studies did not include information on sexual behavior or other potential behavioral risk factors for CT infection.…”