INCIDENT CHLAMYDIA-TRACHOMATIS INFECTIONS AMONG INNER-CITY ADOLESCENTFEMALES

Context.-Adolescents are at highest risk for infection with Chlamydia trachomatis, an important preventable cause of pelvic inflammatory dis ease and subsequent tubal factor infertility in US women. Current guid elines for delivery of adolescent primary care services recommend year ly chlamydia screening for those adolescent females considered to be a t risk. Objectives.-To describe the epidemiology of prevalent and inci dent chlamydia infection among adolescent females to assess the approp riate interval for chlamydia screening and to define risk factors that would identify adolescent females to target for screening. Design.-Pr ospective longitudinal study. Patients.-A consecutive sample of 3202 s exually active females 12 through 19 years old making 5360 patient vis its over a 33-month period, January 1994 through September 1996. Setti ng.-Baltimore, Md, family planning, sexually transmitted disease, and school-based clinics. Intervention.-Testing for C trachomatis by polym erase chain reaction. Main Outcome Measures.-Prevalence and incidence of C trachomatis infections; predictors of positive test result for C trachomatis, Results.-Chlamydia infection was found in 771 first visit s (24.1%) and 299 repeat visits (13.9%); 933 adolescent females (29.1% ) had at least 1 positive test result. Females who were 14 years old h ad the highest age-specific chlamydia prevalence rate (63 [27.5%] of 2 29 cases; P=.01). The chlamydia incidence rate was 28.0 cases per 1000 person-months (95% confidence interval, 24.9-31.5 cases). The median time was 7.2 months to a first positive chlamydia test result and 6.3 months to a repeat positive test result among those with repeat visits . Independent predictors of chlamydia infection-reason for clinic visi t, clinic type, prior sexually transmitted diseases, multiple or new p artners, or inconsistent condom use-failed to identify a subset of ado lescent females with the majority of infections. Conclusions.-A high p revalence and incidence of C trachomatis infection were found among ad olescent females. We, therefore, recommend screening all sexually acti ve adolescent females for chlamydia infection every 6 months, regardle ss of symptoms, prior infections, condom use, or multiple partner risk s.