Trichomonas vaginalis infection-associated risk of cervical cancer: A meta-analysis

Trichomoniasis, caused by the extracellular eukaryotic parasite trichomonas vaginalis, is one of the most common non-viral sexually transmitted infections worldwide. The correlation between trichomoniasis and cervical cancer was ambiguous. This meta-analysis was carried out to determine the relevance between trichomoniasis and cervical cancer. Relevant data from 1985 to 2016 were identified through an extensive search of Medline, Cochrane database, Google Scholar, EMBASE, China National Knowledge Infrastructure. Finally 17 eligible articles covered 7715 individuals with cervical lesions and 67,598 controls were included. Meta-analysis of total eligible studies showed that odds ratio of retrospective studies was 2.06, with 95% confidence interval (95% CI) of 1.77 to 2.39, prospective studies with adjusted relative risk of 1.94 (95% CI = 1.19 to 3.15) and 2.84 (95% CI = 1.32 to 6.12) respectively, and the combined relative risk was 2.03 (95% CI = 1.35 to 3.06). Subgroup analysis indicated that there were significant regional and racial differences in the correlation between trichomoniasis and cervical cancer. Odds ratio of Africa and Europe are 2.43 (95% CI = 1.15 to 5.13) and 1.82 (95% CI = 1.67 to 2.62) respectively. Odds ratio of mixed population is 2.87 (95% CI = 2.00 to 4.12), followed by black and white, Asian with the lowest odds ratio of 1.91 (95% CI = 1.32 to 2.77). In conclusion, our data demonstrate that individuals infected with trichomonas vaginalis have a higher risk of cervical cancer, especially co-infected with Human Papilloma Virus. Besides, there is significant regional and racial variation in the correlation between trichomonas vaginalis infection and risk of cervical cancer.