A prospective cohort study of cigarette smoking and the risk of endometrial cancer

Abstract

Case -control studies have shown inverse associations between cigarette smoking and endometrial cancer risk. However, two small prospective cohort studies have not clearly supported an association. Moreover, quantitative measures of smoking have been examined infrequently. Our aim was to study the association between smoking and endometrial cancer risk in a large prospective cohort. We used proportional hazards models to estimate hazard ratios relating cigarette smoking to endometrial cancer risk among 70 591 women aged 40 -59 years at recruitment into a randomised controlled trial of mammography screening for breast cancer. During an average of 10.6 years of follow-up (751 833 person -years), a total of 403 women were diagnosed with incident endometrial cancer. We found that a reduced endometrial cancer risk was evident only among women who currently smoked 20 cigarettes per day or more (hazard ratio=0.62, 95% CI=0.42 -0.92, P for trend=0.03). There was some suggestion of an inverse association with smoking duration, but this was less clear. The association did not vary with menopausal status, relative body weight, or the use of hormone replacement therapy, but it appeared to be stronger among parous than nulliparous women. The underlying biological mechanisms of this association remain unclear.

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).…”

Smoking, Earlier Menarche and Low Parity as Independent Risk Factors for Gynecologic Cancers in Japanese: A Case-Control Study

“…On the other hand, a decreased risk associated with passive smoking was observed for endometrial cancer, and a decreased risk associated with alcohol drinking was found for ovarian cancer. In Western countries, similar associations have been observed (Lyon et al 1983;Baron et al 1986;Kjaer et al 1996;Terry et al 2002;Viswanathan et al 2005). In Japan, although the evidence is sparse, Hirose et al have reported the increase in cervical cancer risk among active and passive smokers, and Kato et al found a decreased risk associated with alcohol drinking in ovarian cancer (Kato et al 1989;Hirose et al 1996).…”

“…Local immune suppression produced by tobacco smoking, which may enhance HPV persistence, may also affect the development of cervical cancer (Burger et al 1993). The association between smoking and endometrial cancer risk may be attributed to antiestrogenic effects of smoking (Terry et al 2002;Viswanathan et al 2005). Estrogen may promote the development of endometrial cancer.…”

Conditions Associated with Antibodies Against the Tumor-Associated Antigen MUC1 and Their Relationship to Risk for Ovarian Cancer

“…Besides bone fracture and IUD use, a third factor, which may link the etiology of ovarian and endometrial cancer, is smoking. A decreased risk for endometrial cancer is found in smokers, especially current smokers (29,30). The data are less clear for ovarian cancer with two recent studies suggesting that smoking may increase the risk only for mucinous histologic subtypes (31,32).…”