Background: We wanted to determine the prevalence of Chlamydia trachomatis in a sample of young women and to assess risk factors related to sexual behaviour that are predictive of such infection.
Material and methods: 898 healthy, non-pregnant women aged 16 to 24 years attending primary care centres over a two-year period (September 1998 to December 2000) were recruited for the study. Uterine cervix samples were tested for Chlamydia trachomatis and participants were interviewed about their sexual behaviour. Chlamydia test results from 881 samples were valid.
Results: The prevalence of genital Chlamydia trachomatis infection was 2.4% (21/881). In univariable analyses, a high number of lifetime partners (four or more), smoking, previous pregnancy and a previous positive chlamydia test were factors predictive of a positive Chlamydia test. In multivariable analyses, previous pregnancy and a previous positive Chlamydia test were the only significant factors. The number of lifetime partners was higher among women who had been pregnant or previously had tested positively for Chlamydia.
Interpretation: The prevalence of Chlamydia was low in this population. Risk behaviour (frequent change of partners) can be expressed by teenage pregnancy and positive Chlamydia test results and these factors can be used for identification of women who should be tested more frequently than others for Chlamydia infection in a low-prevalence population.