Objectives: The purpose of this study was to evaluate the effect of cigarette smoking and alcohol use on the risk of endometrial cancer. The impact of smoking on serum estrone, estradiol, and androstenedione levels also was examined.
Study design: This hospital-based case-control study included 168 women with endometrial carcinoma and 334 control women.
Results: Women who were current smokers had a lower risk of endometrial cancer than did women who did not smoke (relative rate 0.69; 95% confidence interval 0.40-1.19), whereas women who were exsmokers and women who had never smoked had similar rates (relative rate 0.83; 95% confidence interval 0.46-1.48). There was little overall association between serum estrogen levels and cigarette smoking, although estradiol levels in overweight control subjects were lower among women who were current smokers than among women who had never smoked. Androstenedione levels were slightly higher among women in the control group who smoked than among women in the control group who did not smoke, but the difference was not statistically significant (p = 0.28, two-tailed). Alcohol use was unrelated to endometrial cancer in this study.
Conclusions: The study provides additional support for the hypothesis that smoking is inversely related to endometrial cancer. The inverse smoking association with endometrial cancer may be more directly related to higher serum androstenedione levels than to lower serum estrogen levels except, perhaps, among overweight women.