Tobacco Use and Oral HPV-16 Infection

Oral human papillomavirus type 16 (HPV-16), a sexually transmitted infection, is believed to be responsible for the increase in incidence of oropharyngeal squamous cell cancers in the United States.¹ An association between self-reported number of cigarettes currently smoked per day and oral HPV prevalence has been observed.^2,3 We investigated associations between objective biomarkers reflective of all current tobacco exposures (environmental, smoking, and use of smokeless tobacco) and oral HPV-16 prevalence.

The National Health and Nutrition Examination Survey (NHANES) is a cross-sectional, stratified multistage probability sample of the US population.⁴ The NHANES was approved by the National Center for Health Statistics institutional review board and written informed consent was obtained from participants. During 2009-2012, the response rate was 73.4%. Mobile examination center participants aged 14 to 69 years were eligible for oral HPV DNA testing. Exfoliated oral cells were collected using a 30-second oral rinse and gargle, and tested for HPV-16 as previously reported.²

Computer-assisted self-interviews were used to ascertain self-reported tobacco use and sexual behaviors. Self-reported tobacco use for the past 5 days included any nicotine-containing product. Biomarkers of recent tobacco use included serum cotinine, a major nicotine metabolite, and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a tobacco-specific, carcinogenic metabolite.⁴

Of 20 293 participants interviewed, the analysis was restricted to participants aged 18 to 59 years (n = 8527) with data on oral HPV-16 and recent tobacco use (n = 6887). The principal outcome was oral HPV-16 infection. NHANES sample weights were used to estimate prevalence. Mean biomarker values were compared using Wald tests. For modeling, cotinine and NNAL were log-transformed and considered as continuous and categorical variables. The association of tobacco use with oral HPV-16 was explored using logistic regression. All multivariable models included variables considered significant (2-sided P < .05) in bivariable analysis and important factors based on the literature.² Analyses were performed using SUDAAN software version 11.0.1 (RTI International).

Among 6887 participants, 2012 (28.6%; 95% CI, 26.5%-30.9%) were current tobacco users and 63 (1.0%; 95% CI, 0.8%-1.3%) had oral HPV-16 detected. Current tobacco users were more likely than nonusers to be male, younger, less educated, and to have a higher number of lifetime oral sexual partners (Table 1). In bivariable analysis, self-reported and biological measures of tobacco exposure as well as oral sexual behavior were significantly associated with prevalent oral HPV-16 infection (Table 2). Oral HPV-16 prevalence was greater in current tobacco users (2.0%; 95% CI, 1.3%-3.1%) compared with never or former tobacco users (0.6%; 95% CI, 0.4%-0.9%) (P = .004). Mean cotinine (157.7 ng/mL vs 57.2 ng/mL, P = .002) and NNAL levels (0.36 ng/mL vs 0.12 ng/mL, P = .02) were higher in individuals with vs without oral HPV-16 infection.

All biomarkers of tobacco exposure remained associated with oral HPV-16 infection after adjustment for other factors (Table 2). Significant dose-response relationships were observed between cotinine (P = .02 for trend) or NNAL (P = .01 for trend) levels and odds of oral HPV-16 infection (Table 2). Each log increase in cotinine, approximating 3 cigarettes per day, was independently associated with oral HPV-16 prevalence (adjusted odds ratio, 1.31; 95% CI, 1.07-1.60). Each log increase in NNAL, approximating 4 cigarettes per day, was independently associated with oral HPV-16 prevalence (adjusted odds ratio, 1.68; 95% CI, 1.23-2.28).

In this large cross-sectional, population-based study, we demonstrated statistically significant dose-response relationships between behavioral and objective biomarkers of current tobacco use and oral HPV-16 infection. Tobacco use is an established co-factor for the development of cervical cancer, for which HPV infection is a necessary cause.⁵ Tobacco use has local and systemic immunosuppressive effects⁶; however, the specific biological mechanisms underlying our observed associations are unknown. Tobacco use may alter determinants of oral HPV-16 prevalence, such as incidence, persistence, or reactivation of infection.

These findings highlight the need to evaluate the role of tobacco in the natural history of oral HPV-16 infection and progression to malignancy. Although adjusted for sexual behavior, we cannot entirely exclude the possibility that tobacco use is a marker for risky behavior. Additional limitations include some unstable estimates and a cross-sectional study design that precludes our ability to determine temporality or causation.

Corresponding Authors: Gypsyamber D’Souza, PhD, MS, MPH, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205 (gdsouza2@jhu.edu); and Carole Fakhry, MD, MPH (cfakhry@jhmi.edu).

Author Contributions: Dr D’Souza had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Fakhry, D’Souza.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Fakhry, D’Souza.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Fakhry, D’Souza.

Obtained funding: All authors.

Administrative, technical, or material support: Fakhry, D’Souza.

Study supervision: Fakhry, D’Souza.

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Drs Gillison and D’Souza reported receiving previous research support from Merck Inc. Dr Gillison also reported serving as an unpaid consultant to GlaxoSmithKline. No other disclosures were reported.

Funding/Support: This study was supported by grants P50DE019032, R01DE021395, R01DE023175 from the National Institute of Dental and Craniofacial Research and funding from the Milton J. Dance Head and Neck Center and Merck.

Role of the Funder/Sponsor: The National Institute of Dental and Craniofacial Research, the Milton J. Dance Head and Neck Center, and Merck had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: Timothy S. McNeel, BA (Information Management Services Inc), assisted with statistical analyses and received compensation.