Risk of endometrial cancer in relationship to cigarette smoking: Results from the EPIC study

Abstract

Current epidemiologic evidence indicates that cigarette smoking reduces the risk of endometrial cancer. We examined data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to analyze further aspects of the smoking-endometrial cancer relationship, such as possible modifying effects of menopausal status, HRT use, BMI and parity. In a total of 249,986 women with smoking exposure and menopausal status information, 619 incident endometrial cancer cases were identified during 1.56 million person-years of follow-up. Among postmenopausal women, the hazard ratio (HR) for current smokers versus never smokers was 0.70 (95% CI 5 0.53-0.93), while it was 1.75 (95% CI 5 1.13-2.70) among premenopausal women at recruitment. After adjustment for risk factors, the HR for postmenopausal women was slightly attenuated to 0.78 (95% CI 5 0.59-1.03). No heterogeneity of effect was observed with HRT use or BMI. Among premenopausal women, current smokers of more than 15 cigarettes per day or who smoked for 30 years or more at the time of recruitment had a more than 2-fold increased risk of endometrial cancer compared to never smokers (HR 5 2.54; 95% CI 5 1.47-4.38 and HR 5 2.23; 95% CI 5 1.04-4.77, respectively). Past smoking was not associated with endometrial cancer risk, either among pre-or post-

A population-based cohort study on sun habits and endometrial cancer

“…In our study, smoking women had a decreased risk of endometrial cancer, which is in agreement with other prospective cohort studies (Terry et al, 2002;Viswanathan et al, 2005;Al-Zoughool et al, 2007;Loerbroks et al, 2007).…”

Body Mass Index, Hormone Replacement Therapy, and Endometrial Cancer Risk: A Meta-Analysis

“…Differences in the BMI distribution across studies are a potential source of heterogeneity when expressing results on a linear scale, as it ignores that the true relationship between the logarithm of the relative risk and BMI is probably not linear. Smoking may be an additional confounder as it is antiestrogenic (58) and there is evidence that the risk of endometrial cancer is attenuated for a given BMI category in smokers compared with nonsmokers (59,60). However, the present analysis was not designed to assess the complex triangulated relationship of BMI, HRT, and smoking, and indeed our search failed to identify a study that assessed all three risk factors interactively.…”

Hormones and receptors in endometrial cancer

“…The increased enzyme activity results in greater clearance of estrogens from the circulation and a reduction in end organ effect 102 . Epidemiological studies have demonstrated a 20-30% reduction in the risk of endometrial cancer in women who smoke 103,104 . Endogenous estrogen production also occurs via autonomous synthesis within some ovarian tumors.…”