Objective: Although human papillomavirus causes essentially all cervical carcinoma, cofactors may differ by cancer histologic type. We examined human papillomavirus genotypes and sexual and reproductive risk factors for cervical adenocarcinoma and squamous cell carcinoma.
Study design: One hundred twenty-four women with adenocarcinoma, 139 women with squamous cell carcinoma, and 307 control subjects participated in this case-control study. Logistic regression analyses were performed to calculate odds ratios and CIs.
Results: Human papillomavirus 18 was associated most strongly with adenocarcinoma (odds ratio, 105; 95% CI, 23-487). Human papillomavirus 16 was associated most strongly with squamous cell carcinoma (odds ratio, 30; 95% CI, 12-77). More than three lifetime sexual partners was a risk factor for adenocarcinoma (odds ratio, 2.1; 95% CI, 1.1-4.0) and squamous cell carcinoma (odds ratio, 3.0; 95% CI, 1.6-5.9). Even being pregnant was associated inversely with adenocarcinoma (odds ratio, 0.4; 95% CI, 0.2-0.8). Five or more pregnancies was associated with squamous cell carcinoma (odds ratio, 2.2; 95% CI, 0.9-5.4).
Conclusion: The relative importance of human papillomavirus genotypes 16 and 18 and the reproductive co-factor differences suggest distinct causes for cervical adenocarcinoma and squamous cell carcinoma.