Co-factors related to the causal relationship between human papillomavirusand invasive cervical cancer in Honduras

Background A case-control study was conducted in Honduras to identify co-fa ctors in the carcinogenic pathway by which human papillomavirus (HPV) cause s invasive cervical cancer. Methods Ninety-nine cases aged 23-65 (median 47) years participated. Two co ntrols were matched to each case by age and clinic where they first present ed for cytological screening; controls had no cervical abnormalities. Infor mation on risk factors was obtained by personal interviews in the clinics r egarding sociodemographic, reproductive and behavourial characteristics. Hu man papillomavirus was detected in cervical scrapes by general primer-media ted polymerase chain reaction (PCR) followed by sequence analysis to identi fy the different types present. Results All cases had squamous cell tumours and most were FIGO (Internation al Federation of Gynecologists and Obstetricians) class II or higher; HPV w as strongly associated with cervical cancer (odds ratio [OR] = 7.66, 95% CI :3.88-15.1). Among HPV-positive women, dose-response relationships were obs erved for education, age at first intercourse and exposure to wood smoke th at persisted after adjustment for previous screening. Among HPV-negative wo men, the number of sexual partners and parity were associated with cervical cancer. The protective effect of previous cytological screening operated i ndependently of HPV. Conclusions Our findings speak for the powerful role that both primary and secondary education plays in fostering a Lifestyle that reduces the risk of invasive cervical cancer. The data suggest that important elements of such a lifestyle include later age at first sexual intercourse, a limited numbe r of pregnancies, greater likelihood of undergoing cytological screening an d reduced exposure to carcinogens in the household environment.