Case-control study of risk factors for cervical squamous cell neoplasia in Denmark. IV: role of smoking habits.
The role of smoking and other risk factors for cervical neoplasia was investigated in a population-based case-control study of 586 women with histologically verified cervical squamous-cell carcinoma in situ (CIS), and 59 women with invasive squamous-cell cervical cancer from Copenhagen. Controls were randomly selected from the general female population using the computerized Danish Central Population Register. After adjustment for a variety of confounding variables, which were all significantly associated with CIS risk and included age, number of partners, proportion of sexually active life without barrier contraceptive use, years with intra-uterine devices, number of births, and age at first episode of genital warts (as a proxy measure for human papillomavirus exposure), current cigarette smoking was found to be significantly associated with CIS [adjusted relative risk (RR) = 2.4; 95% confidence interval (CI): 1.7-3.4]. Ex-smokers had a lower, but still significantly increased risk (RR = 1.6; 95% CI: 1.0-2.7). A dose-response relationship was present, especially for number of cigarettes smoked per day. In contrast, the crude estimates showed a weak association between invasive cervical cancer and smoking, which however disappeared after confounder control. The results of the present study support the hypothesis implicating smoking as a risk factor for CIS.
Kjaer
S K
SK
Danish Cancer Society, Division for Cancer Epidemiology, Copenhagen, Denmark.
Engholm
G
G
Dahl
C
C
Bock
J E
JE
D000328:Adult; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D012042:Registries; D012306:Risk; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology / Q000209:etiology*; D002578:Uterine Cervical Dysplasia / Q000453:epidemiology / Q000209:etiology*