Introduction: Chlamydia is the most common sexually transmitted bacterial infection in Denmark. Each year 13-14,000 cases are diagnosed; of these about 3000 occur in men. In order to describe the prevalence of chlamydia among young men, screening for chlamydia was conducted in those liable for military service and coming before the medical board.
Materials and methods: Of 2500 men coming before the medical boards in North Jutland State County, Arhus State County, and Copenhagen County during the winter of 1996-97, 1345 men aged 17-32 (median 18 years) were entered in the study. The participants sent a urine sample and a filled-in questionnaire to Statens Serum Institut. The urine samples were analysed by an in-house PCR and the test results were sent to the participant; if permission had been granted, the positive test results were further sent to the general practitioner, along with a second questionnaire.
Results: Chlamydia was found in 4.8% (65/1345) of all participants and in 6.9% of those sexually active. In North Jutland State County 7.1 and 9.8%, respectively, had chlamydia, whereas the corresponding figures for Arhus State County and Copenhagen County were about 4% and 6%. Two-thirds of the patients had no symptoms of urethritis.
Discussion: The results of this study indicate that a considerable reservoir of unrecognised chlamydia must exist in young men. The prevalence of chlamydia was higher in North Jutland State County than in the other two districts. One explanation could be that there is more focus on sexually transmitted infections and contact tracing in the largest cities than in the rest of the country.