RESUMO
BACKGROUND: Human papillomavirus and Chlamydia trachomatis share the same route of sexual transmission and possess similar risk factors, indicating that coinfection may act synergistically in the induction of epithelial cell abnormalities. OBJECTIVE: This study aimed to determine the prevalence of human papillomavirus and Chlamydia trachomatis in adolescents and young women and identify factors associated with coinfection. STUDY DESIGN: This cross-sectional study included 276 female participants, aged 15-24 years, who were sexually active. Interviews were conducted and cervical specimens were collected for cervical smears and molecular tests. All cervical specimens were tested for 27 human papillomavirus genotypes by polymerase chain reaction amplification and hybridization to a human papillomavirus linear array. Detection of Chlamydia trachomatis was performed by polymerase chain reaction using primers directed to the region encoding the cryptic plasmid. Bivariate and multivariate analyses were performed to evaluate the factors associated with coinfection with human papillomavirus and Chlamydia trachomatis. The odds ratio, the adjusted odds ratio, and the 95% confidence interval were calculated. RESULTS: The prevalence of infection by Chlamydia trachomatis and human papillomavirus was 9.1% (95% confidence interval, 5.61-12.4) and 47.1% (95% confidence interval, 41.0-53.2), respectively. The prevalence of coinfection with human papillomavirus and Chlamydia trachomatis was 5.8% (95% confidence interval, 3.3-9.2); coinfection with 1 human papillomavirus type was 3.3% (95% confidence interval, 1.5-6.1) and with multiple types was 2.5% (95% confidence interval, 1.0-5.2). The prevalence of cytological abnormalities was 12.3% (95% confidence interval, 8.6-16.79). Human papillomavirus infections of high oncogenic risk were more prevalent (85.4%). Factors independently associated with coinfection of human papillomavirus/Chlamydia trachomatis obtained by multivariate analysis were the initiation of sexual activity under 16 years of age with an an odds ratio of 4.9 (95% confidence interval, 1.0-23.63; P = .05) and cytological abnormalities with an odds ratio of 10.7 (95% confidence interval, 1.9-59.5; P = .01), which indicates there is risk for the detection of cytological abnormalities in adolescents and young women coinfected with human papillomavirus/Chlamydia trachomatis. CONCLUSION: The prevalence of coinfection among our study population was of a magnitude that warrants attention by public health services. Adolescents and young women should be monitored for Chlamydia trachomatis infection and vaccinated against human papillomavirus. The association between cytological abnormalities and coinfection with human papillomavirus and Chlamydia trachomatis indicates the potential synergistic role of these infections in carcinogenesis of the cervix.