Background and objectives: Trichomonas vaginalis infection is probably one of the most common sexually transmitted diseases. The epidemiology of this disease has long been ignored, and not much is known about its natural history and risk factors.
Goals: The authors conducted this study to define the incidence rates of T. vaginalis infection and to investigate risk factors for the infection.
Study design: A prospective study was carried out on a cohort of 16,797 women followed up from 1974 to 1985 within the framework of a cervical screening program in Jingan, China. Personal interviews were conducted by trained interviewers.
Results: A total of 1489 new cases of T. vaginalis infection were diagnosed with 132,946 person-years of observation. In a multivariate analysis, the increased risk was associated with multiple sexual partners (P = 0.0124) and greater number of induced abortions (P = 0.0028). The relative risks were 1.3 (95% confidence interval [CI], 1.1 to 1.5) for smokers and 1.5 (95% CI, 1.2 to 2.0) for those who drink alcohol. An inverse relationship was observed in older women and in women with cervical atrophy.
Conclusions: This study confirmed the relationship between T. vaginalis and multiple sexual partners and suggests that the risk for T. vaginalis also may be related to life-style risk factors.