Genital infection by Chlamydia trachomatis in Lisbon: prevalence and risk markers.
BACKGROUND
There is little information about the prevalence and risk markers for Chlamydia trachomatis infections in Portugal.


OBJECTIVE
Our aim was to assess the prevalence of C. trachomatis genital infection and to study variables associated with this infection in a group of sexually active women aged < or =30 years living in the Lisbon area and to estimate the prevalence of C. trachomatis infection among partners of infected patients.


METHODS
A systematic sample of women observed in general practice family planning and teenager clinics was collected. A questionnaire was administered, followed by a pelvic examination. A first-catch urine sample was taken for polymerase chain reaction (PCR) Amplicor assay. When a sample tested positive, the woman was invited to obtain a urine sample from her partner. Socio-demograhic, behavioural and clinical variables were studied and their association with the PCR Amplicor result was assessed.


RESULTS
A total of 1108 women, aged between 14 and 30 years, were studied. Fifty-one women (4.6% of total sample) tested positive for C. trachomatis. The prevalence of infection was slightly higher in patients aged < or =19 years (5.3%) than in age groups 20-25 (4.8%) and 26-30 years (3.9%). African ethnicity was related to a higher percentage of infection than European ethnicity: 9.8% versus 3.8%, P= 0.0067. Use of condoms "sometimes/never" was associated with a higher prevalence of infection: 5.2% versus 2.3% in those responding "always/almost always" (P= 0.0447). An altered cervix was associated with a higher prevalence of infection: 7.3% versus 3.7% with a normal cervix (P= 0.0106). Urine samples were obtained from 16 partners of infected patients. Six partners (37.5%) tested positive for C. trachomatis.


CONCLUSIONS
A 4.6% prevalence of C. trachomatis genital infection was found. African ethnicity, using condoms "sometimes/never" and an altered cervix were associated with C. trachomatis infection, but showed low positive predictive value for C. trachomatis infection. Younger age may be associated with a slight increase in risk. Contact tracing for diagnosis and treatment remains a difficult issue to approach effectively.
Instituto de Medicina Preventiva, Faculdade de Medicina de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisbon, Portugal. abritosa@sapo.pt
Armando
A
Brito de Sá
João Paulo
JP
Gomes
Sílvia
S
Viegas
Maria Arminda
MA
Ferreira
Albertina
A
Paulino
Maria dos Anjos
Mdos A
Catry
D000293:Adolescent; D000328:Adult; D002690:Chlamydia Infections / Q000453:epidemiology*; D002692:Chlamydia trachomatis; D005260:Female; D005831:Genital Diseases, Female / Q000382:microbiology*; D006801:Humans; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors