Genital Chlamydia trachomatis infections in Uppsala County, Sweden, 1985-1993: declining rates for how much longer?

Abstract

Background: In Uppsala County, between 1985 and 1993, examinations for Chlamydia trachomatis were being performed in a central laboratory. A change in national sexually transmitted disease legislation in 1988 encouraged screening.

Goals of this study: To analyze trends in detection rates of genital chlamydial infections by age, sex, and clinic type, and to assess the influence of the legislation change.

Study design: This was an analysis of 119,892 tests, representing 95.4% of all specimens sampled. Eighty-six percent of the samples were cultured, 14% were examined by enzyme immunoassay.

Results: Seventy-nine percent of specimens came from women. 7,989 positive samples were identified. Detection rates declined from 107.2 per 1,000 in 1985 to 32.3 in 1993 in women and from 183.3 to 70.7 in men. Positivity rates were highest in sexually transmitted disease and youth clinics and lowest in private practices. Among female youths, rates leveled off in later years, but the rates increased in male youths. The legislation change reduced the probability of a positive test in men but not in women.

Conclusions: Genital chlamydial infection generally declined. However, among youths, an increase has occurred in recent years. Continued screening and the introduction of noninvasive diagnostic methods for males is warranted, particularly in youth clinics. Selective screening may be more cost-effective in other age groups.