Sexual behaviour and smoking as determinants of cervical HPV infection and of CIN3 among those infected: a case-control study nested within the Manchester cohort.
To distinguish risk factors for acquisition of cervical human papillomavirus (HPV) infection from the determinants of neoplasia among infected individuals we have conducted a three-arm case-control study nested within a large population-based cohort of women (the Manchester cohort) screened for HPV at entry using L1 consensus primer PCR. The study includes 181 HPV-positive controls who did not develop high-grade cervical intraepithelial neoplasia (CIN3) during follow-up, 203 HPV-negative controls, and 199 HPV-positive cases with histologically confirmed CIN3. Detailed information on sexual, reproductive and gynaecological history, oral contraceptive use and smoking was obtained at face-to-face interview. There was a striking division between risk factors for infection and those predictive of disease. Comparing the HPV-positive against the HPV-negative controls, the only risk factors for infection were number of sexual partners (OR for six or more = 3.89; 95% Cl = 1.99-7.62), a relatively recent new sexual relationship (OR for a new partner within the previous 2 years = 4.17; 95% Cl = 2.13-8.33), and a history of previous miscarriage (OR = 2.59; 95% Cl = 1.28-5.21). The determinants of CIN3 among infected women were, in contrast, early age at first intercourse (OR for 16 years old or less = 3.23; 95% Cl = 1.33-7.69), a long time since starting a new sexual relationship (OR for 6 years or more = 4.94; 95% Cl = 2.51-9.71), and cigarette smoking, with strong evidence for a dose- response (OR for current smoking habit 20+ per day = 2.57; 95% Cl = 1.49-4.45). Oral contraceptive use was not significantly associated with either HPV infection or CIN3.
Deacon
J M
JM
Section of Epidemiology, Institute of Cancer Research, 15 Cotswold Road, Belmont, Sutton, Surrey, SM2 5NG, UK.
Evans
C D
CD
Yule
R
R
Desai
M
M
Binns
W
W
Taylor
C
C
Peto
J
J
D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D027383:Papillomaviridae; D030361:Papillomavirus Infections / Q000150:complications* / Q000453:epidemiology / Q000821:virology; D012307:Risk Factors; D012725:Sexual Behavior; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology / Q000235:genetics; D014412:Tumor Virus Infections / Q000150:complications* / Q000453:epidemiology / Q000821:virology; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000821:virology; D002578:Uterine Cervical Dysplasia / Q000453:epidemiology / Q000209:etiology* / Q000821:virology