Background: The epidemiology of Chlamydia trachomatis infection in men is not well defined, especially among those who are asymptomatic or show no signs of infection. Established C. trachomatis screening programs for women have demonstrated the benefit of routine screening in reducing prevalence over time, but the yield and benefit of screening asymptomatic men are unclear.
Methods: Cross-sectional study of C. trachomatis prevalence and associated risk factors among men tested at sexually transmitted disease (STD) clinics in Alaska, Idaho, Oregon, and Washington. We analyzed data from 43,094 men universally tested from 1997 to 1999 at 103 STD clinics, and assessed age-specific prevalence of infection, controlling for signs of infection (urethritis diagnosed by clinician) and report of sexual contact to a person with an STD (defined as "contact").
Results: Overall prevalence of C. trachomatis was 10.3%. Age-specific prevalence was highest among men aged 18 to 19 years and lowest among those aged >29 years, regardless of signs of infection upon examination or contact to a person with an STD. If these factors and age <25 years had been used to direct C. trachomatis testing at STD clinics, 59% of men would have been tested and 91% of positives would have been detected.
Conclusions: Using either the presence of clinical signs or report of a sex partner with an STD in combination with selective screening of all men aged <25 years detects the majority of infections and, in our population, would have considerably reduced the number of negative tests performed.