Objectives: To assess the prevalence of sexually transmitted infections (STI) and relationships between them and sociodemographic/behavioural data in the major Venereology Clinic in Lisbon.
Methods: Every patient attending this STI clinic for the first time in the first 17 weeks of 2007 was enrolled in this study. Early syphilis, Chlamydia trachomatis infection, gonorrhoea, human immunodeficiency virus (HIV) first diagnosed and genital warts were considered for the study of statistical associations with sociodemographic/behavioural variables or other STI. Data were analysed with an exact significance level of 5%.
Results: A total of 743 patients were included. In women (n = 296), the only significant associations found were for C. trachomatis and being non-Caucasian (OR = 2.13, CI 1.17-3.9) or being younger than 25 years (OR = 1.9, CI 1.31-2.79). Men who have sex with men (176 of the 447 male patients) contributed to 39% of the STI, although more than half of the early syphilis, gonorrhoea and HIV cases were diagnosed in this group.
Conclusions: Despite its limitations, our study allows some insight into the relationships between sociodemographic factors and STI in a selected population attending Lisbon's major Venereology Clinic. The results were similar to those of other European studies and to recent trends in STI, but differ in the association between C. trachomatis infection and non-Caucasian women, which is similar to cities with significant African minorities. Attention should be given to the associations found between men who have sex with men and STI such as gonorrhoea, syphilis and HIV, as these associations can lead to serious difficulties in the control of HIV infection in Portugal.