The control of reproductive tract infections (RTIs), especially sexually transmitted infections (STIs), is an urgent health priority in many countries (1-4). Policy-makers should be able to set health sector priorities in accordance with the disease burden, the availability and estimated cost-effectiveness of technical solutions, and other variables (5). However, this is often difficult because of a paucity of epidemiological data and the absence of a functional surveillance system for such infections, other than infection with human immunodeficiency virus (HIV).
A recent review (6) of cross-sectional studies of RTI prevalence in general population samples found only five surveys from south Asia, including the present one, which included laboratory results. One of these surveys considered only the prevalence of vaginal infections. Four studies in India relied entirely on clinical diagnosis to define the presence of infection, notwithstanding the lack of correlation between clinical and laboratory results (6). Global burden of disease calculations for these infections have been based on a restricted number of survey results from facility-based or convenience-based samples. There were no studies from Bangladesh and only. one population-based survey from India was available (7).
We therefore conducted a population-based survey of RTI/STI prevalence in a rural area of Bangladesh to determine the risk factors for RTIs.
Materials and methods
Study site and population
The study was undertaken in the Matlab area of Bangladesh. Demographic surveillance and field trials have been conducted in this area by the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) since the 1960s. The Matlab field research station was set up to learn about the epidemiology of common diseases (8) and to test the efficacy or impact of proposed interventions before their implementation nationally. We have previously reported the results of testing syndromic management for STI control in this area (9).
Matlab, which is situated 60 km south-east of Dhaka, has a population of 210 000 people in 142 villages and is included in ICDDR,B's demographic surveillance system (DSS), which records all marriages, births, deaths, inward and outward migration, and internal movements. The area is subdivided into an intervention area where a maternal, child health and family planning programme carries out intervention studies, and a comparison area where all health services are provided by the government system. A record-keeping system (RKS) is employed to gather information on reproductive status and morbidity episodes among married women aged 15-50 years and on morbidity among children aged 0-4 years in the intervention area; it is updated monthly through household visits in the intervention area.
This study was conducted in the intervention area by using DSS and RKS computerized population lists as the basis for sampling frames. Sample sizes were based on the expected prevalence of selected RTIs as found in previous surveys in Bangladesh (10, 11). For cultural and ethical reasons it was not felt appropriate to include unmarried women and girls in a survey of RTI/STI prevalence. A systematic sample of married non-pregnant women aged 15-50 years was therefore drawn from the RKS registered population in August 1995. Since there were no restrictions on the inclusion of men, the census-derived DSS list was used as the sampling frame for the selection of a systematic sample of men of the same age.
Approval for the study was obtained from the ICDDR,B ethical review committee. The participants were informed that they would be tested for RTIs and STIs and that they would be offered free treatment if found to be infected. Informed consent was obtained in all cases. HIV testing was carried out in accordance with the principles of unlinked anonymous testing, a well-recognized method for obtaining an unbiased assessment of the prevalence of HIV infection in a population (12-14). …