The interrelation of demographic and geospatial risk factors between four common sexually transmitted diseases.

Objectives: To examine the interrelation between demographic and geospatial risk factors for gonorrhoea, chlamydia, genital warts, and genital herpes.

Design: We analysed age, sex, ethnicity, socioeconomic status, and area of residence for Leeds residents aged 15-54 with Neisseria gonorrhoeae, genital Chlamydia trachomatis, first episode genital herpes, and first episode genital warts during 1994-5. The 1991 UK census provided denominator population information.

Results: Regression analysis showed that young age (15-24 years), ethnicity (with a gradient of risk black >white >Asian), and residence in inner city areas of deprivation were independent risk factors for all STDs. There were highly significant correlations in the geospatial distribution of incidence rates between the four infections. However, there was variation in the degree of central urban clustering, with gonorrhoea having the most restricted, and genital warts and chlamydia the widest distribution. 31% of all disease occurred in the four inner city census wards, representing 15% of the population.

Conclusion: These results are in keeping with core group theory applying in a unified manner to the four most common UK sexually transmitted diseases in this urban area. Population based studies are needed to clarify whether ethnicity is associated with differing sexual behavioural or mixing patterns. Our data suggest that chlamydia screening in women <25 years of age could detect 70% of cases in the community, that such programmes should give particular emphasis to implementation in core group areas, and that they could function as unifying strategies for the control of most common STDs within urban areas.