Smoking worsens the prognosis of mild abnormalities in cervical cytology.

OBJECTIVE

To examine the effect of smoking on the incidence of low- and high-grade cervical intraepithelial neoplasia (CIN) in women with a baseline Pap smear of atypical squamous cells (ASC) or a low-grade squamous intraepithelial lesion (LSIL).

DESIGN

Prospective study in which a cohort of women with normal colposcopy and ASC/LSIL at baseline were followed at 6-month intervals of up to 36 months. Women were grouped in post-hoc analysis according to their smoking behavior: never (or past) smokers and current smokers.

SETTING

This report was based on data from the Latin American Screening Study, conducted in Sao Paulo, Campinas, Porto Alegre (Brazil) and Buenos Aires (Argentina).

POPULATION

A subset of 150 women derived from a cohort of 1,011 women.

METHODS

Multivariate Cox analysis and Kaplan-Meier curves were used.

MAIN OUTCOME MEASURES

Low- and high-grade CIN during follow-up.

RESULTS

The only factor related to an increased risk of developing CIN was the positive high-risk (hr) HPV status (hazard ratio (HR) = 3.42; 95% CI: 1.11-9.43). A total of 21 cases of incident CIN were detected during follow-up. Of these, 11 appeared in the group of 67 smokers and 10 among the 83 non-smoker women (log-rank, p=0.33). Smoking status was not associated with the risk of developing CIN (HR = 0.73; 95% CI: 0.40-1.33). However, when restricting the analysis to high-grade CIN only (11 cases), the probability of developing the disease was significantly higher among smokers (p=0.04).

CONCLUSIONS

Smoking contributes additional risk for developing high-grade CIN in women with ASC or LSIL cytology but normal colposcopy.