HIV modifies the effect of tobacco smoking on oral human papillomavirus infection

Background. People living with HIV (PLWH) are more likely to smoke and harbor oral human papillomavirus (HPV) infections, putting them at higher risk for head and neck cancer. We investigated effects of HIV and smoking on oral HPV risk. Methods. Consecutive PLWH (n = 169) and at-risk HIV-negative individuals (n = 126) were recruited from 2 US health centers. Smoking history was collected using questionnaires. Participants provided oral rinse samples for HPV genotyping. We used multivariable logistic regression models with interaction terms for HIV to test for smoking effect on oral HPV. Results. PLWH were more likely to harbor oral HPV than HIV-negative individuals, including α (39% vs 28%), β (73% vs 63%), and γ-types (33% vs 20%). HIV infection positively modified the association between smoking and high-risk oral HPV: odds ratios for smoking 3.46 (95% confidence interval [CI], 1.01-11.94) and 1.59 (95% CI,.32-8.73) among PLWH and HIV-negative individuals, respectively, and relative excess risk due to interaction (RERI) 3.34 (95% CI, −1.51 to 8.18). RERI for HPV 16 was 1.79 (95% CI, −2.57 to 6.16) and 2.78 for β1-HPV (95% CI, −.08 to 5.65). Conclusion. Results show tobacco smoking as a risk factor for oral HPV among PLWH.