Screening strategy for asymptomatic chlamydial infection of students in nonmedical settings in Japan

Objective: To try a new screening strategy for asymptomatic chlamydial infection among students for more accurate and efficient screening of infected individuals in nonmedical settings.

Methods: Population-based cross-sectional surveys were carried out in campus settings for general student populations using anonymous identification numbers and polymerase chain reaction testing of urine specimens for Chlamydia trachomatis; online access to test results via mobile phones was provided. All universities and junior colleges and most professional schools in a prefecture in Japan took part in this screening program. Subjects comprised 10,111 asymptomatic student volunteers „18 and over years old (5986 females, 4125 males). Prevalence and risk factors of asymptomatic infection were determined on the basis of survey results for subjects with positive results to urine testing for C. trachomatis.

Results: The prevalence of asymptomatic chlamydial infection was 9.6% for females and 6.7% for males. Lifetime history of „4 and over sexual partners (females: odds ratio, 3.46; 95% confidence interval, 2.63-4.58; males: 1.90; 1.28-2.81), inconsistent condom use (females: 2.52; 1.78-3.57; males: 4.00; 2.44-6.59), and 6-month history of „2 and over sexual partners (females: 1.55; 1.19-2.03; males: 1.48; 1.01-2.17) represented significant risk factors for both sexes. Using lifetime history of „4 and over sexual partners or inconsistent condom use as selective criteria allowed detection of 90.4% of infected females from 43.2% of the screened female population, and detection of 87.4% of infected males from 40.0% of the screened male population.

Conclusions: On the basis of the resulting accurate epidemiological data, using risky sexual behaviors as a simple selective criteria will allow for efficient screening of infected individuals in nonmedical settings.