Objective: To evaluate the effect of multiple human papillomavirus (HPV) infection on the prevalence of cervical intraepithelial neoplasia (CIN) among women undergoing colposcopy following a cytological diagnosis of atypical squamous cells of undetermined significance (ASCUS) or low grade squamous intraepithelial lesions (LSIL).
Methods: HPV type-specific sequences of 15 high-risk and 10 low risk types were detected by the line probe, INNO-LiPA HPV genotyping assay before colposcopic examination and targeted biopsies. Multinomial logistic regression was used to evaluate the effect of multiple infection on pathologic outcome adjusting for confounders.
Results: The prevalence of HPV infection in the 1218 women enrolled was 69.9% (851/1218). HPV 16 (37.4%), 31 (26.1%), 51 (17.4%), 52 (15.7%) and 18 (14%) were the commonest viral types identified. Overall, the rates of multiple infection were 22.5% (153/680) among subjects with negative colposcopy/biopsy, 63.6% (218/343) and 79.5% (155/195) among those with CIN 1 and CIN>or=2, respectively (p for trend <.001). The corresponding rates among subjects uninfected by HPV 16 or 18 were 13.5% (77/572), 57.4% (112/195) and 62% (48/77), respectively (p for trend <.001). In multinomial logistic regression, the odds ratio of CIN>or=2 in multiple high risk as compared to single high risk HPV infection was 4.33 (95% confidence intervals=2.32-7.14) in the overall population and 2.76 (95% confidence intervals=1.36-5.59) among women uninfected by HPV 16 or 18.
Conclusions: Multiple HPV infection is a significant risk factor for CIN>or=2 among women undergoing colposcopy because of ASCUS/LSIL.