Increased risk of oncogenic human papillomavirus infections and incident high-grade cervical intraepithelial neoplasia among smokers: experience from the Latin American screening study.

BACKGROUND

The purpose of this study was to assess the effect of smoking on the prevalence and incidence of high-risk human papillomavirus (hr-HPV) infection and cervical intraepithelial neoplasia (CIN) in a large sample of Latin American women.

METHODS

The study examines baseline data on over 12,000 women included in the Latin American Screening Study (Brazil and Argentina), and over 1000 women followed-up for a period of 36 months. Three groups were formed: never smokers, current, and past smokers. The prevalence of hr-HPV infection and CIN were compared between the study groups. In the prospective analysis, women were controlled at 6-month intervals to assess the cumulative risk of incident hr-HPV infection, smear abnormalities, and CIN.

RESULTS

A higher prevalence (21.7%) of hr-HPV infection was found among current smokers as compared to never smokers (16.5%) or past smokers (13.5%). Being current smoker was significantly (P <0.01) associated with hr-HPV detection (OR = 1.6; 95% CI = 1.2-2.1). Being a current smoker was a significant predictor of incident hr-HPV during the follow-up [Hazards ratio (HR) = 1.4; 95% CI 1.0-1.9]. For incident CIN2+, being a past smoker (HR = 3.6; 95% CI 1.6-9.8) or current smoker (HR = 3.6; 95% CI 1.5-8.6) were the significant independent predictors. Current and past smokers had a significantly increased risk of incident CIN2+ (P <0.01).

CONCLUSIONS

Smoking increases the risk of contracting hr-HPV infection and modifies the effect of a persistent hr-HPV infection by further increasing the risk of developing CIN2+. It seems that this effect modification persists over several years after smoking cessation.