Bacterial Vaginosis Decreases the Risk of Cervical Cytological Abnormalities

Genital tract infections, including vulvovaginal candidiasis and bacterial vaginosis, have emerged as potential modulators of persistent human papillomavirus (HPV) infections causing cervical cytologic abnormalities and cervical cancer. This study aimed to investigate whether vulvovaginal candidiasis or bacterial vaginosis had an additional effect on HPV infection and thus caused such abnormalities. ThinPrep cytologic tests were used to detect cytologic abnormalities, vulvovaginal candidiasis, and bacterial vaginosis in 14,679 women. Cytologic abnormalities included atypical squamous cells of undetermined significance, low-grade squamous intraepithelial lesions, high-grade squamous intraepithelial lesions, atypical squamous cells-cannot exclude HSIL, and squamous cell carcinoma. Logistic regression Model 1 (univariate regression) and Model 2 (multivariate logistic regression analysis adjusted for age combined with HPV infection) were used to analyze the association between bacterial vaginosis and cytologic abnormalities, or vulvovaginal candidiasis and cytologic abnormalities, alone or in the presence of HPV infection. Bacterial vaginosis infection rates were found to be significantly higher in the cytology-negative group among all participants and those with HPV infection (P = 0.003, P < 0.001, respectively). Analyses using Model 1 and Model 2 both pointed to bacterial vaginosis as a protective factor against cytologic abnormalities for all participants (OR = 0.36, 0.17, respectively, P < 0.05) and for HPV-infected participants (OR = 0.17, 0.16, respectively, P < 0.05). Neither vulvovaginal candidiasis nor vulvovaginal candidiasis + HPV was significantly associated with the incidence of cytologic abnormalities based on Model 1 (OR = 0.94, 0.71, respectively, P > 0.05) and Model 2 (OR = 0.91, 0.74, respectively, P > 0.05). Furthermore, neither vulvovaginal candidiasis nor bacterial vaginosis increased the incidence of cytologic abnormalities regardless of HPV infection status, while bacterial vaginosis might possibly prevent cytologic abnormalities in women coinfected by HPV.

Neither vulvovaginal candidiasis nor bacterial vaginosis was found to increase the incidence of cervical cytologic abnormalities with or without the presence of HPV. On the contrary, bacterial vaginosis may play a role in preventing cytologic abnormalities in women with HPV coinfection.