Association of Trichomonas vaginalis and Cytological Abnormalities of the Cervix in Low Risk Women

OBJECTIVE Is Trichomonas vaginalis (TV) an inducing factor for the development of (pre-)cancerous lesions of the cervix? DESIGN Cross sectional study. SETTING Screening healthy Belgian women with low infection risk. SAMPLE 63,251 consecutive liquid based cervical samples. METHODS Real time quantitative PCR for presence of TV, 18 HPV types and Pap smear analysis of cytologic abnormalities. MAIN OUTCOME MEASURES Association of TV and HPV with cervix dysplasia. RESULTS The overall prevalence of TV DNA was 0.37%, of low risk HPV 2%, of high risk HPV 13.2%, and 8.8 % had cytological abnormalities. Both LR-HPV and HR-HPV were significantly associated with all cytological abnormalities. Presence of TV was associated with LR- and HR-HPV, ASC-US and HSIL, but not with other abnormalities. All women with TV and HSIL also had HR-HPV, while the latter was present in only 59% of women with TV and ASC-US. Amongst HPV negative women, TV was found in 1.3% of women with ASC-US, but only in 0.03% of women with normal cytology (OR 4.2, CL95% 2.1-8.6). In HR-HPV positive women, presence of TV increased the likelihood of cytological abnormalities somewhat (P=0.05), mainly due to an increase in ASC-US and LSIL, but not HSIL. CONCLUSIONS We conclude that TV infection is associated with both LR and HR-HPV infection of the cervix, as well as with ASC-US and HSIL. TV is a concomitant STI, but is not thought to be a co-factor in the causation of HSIL and cervical cancer. However, TV may cause false positive diagnoses of ASC-US.