title: Cigarette smoking and endometrial cancer risk: the modifying effect of obesity.
abstract: The objective of this study was to evaluate the association between cigarette smoking and endometrial cancer risk by investigating potential modifying effects of menopausal status, obesity, and exogenous hormones. We pooled data from three case-control studies with the same study design conducted in Italy and Switzerland between 1982 and 2006. Overall, 1446 incident endometrial cancers and 4076 hospital controls were enrolled. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models, conditioned on study and centre, and adjusted for age, period of interview, age at menarche, parity, and body mass index. In comparison with never smokers, current smokers showed reduced endometrial cancer risk (OR: 0.80; 95% CI: 0.66-0.96), with a 28% decrease in risk for smoking ≥ 20 cigarettes/day. The association did not vary according to menopausal status, oral contraceptive use, or hormone replacement therapy. However, heterogeneity emerged according to body mass index among postmenopausal women, with obese women showing the greatest risk reduction for current smoking (OR: 0.47; 95% CI: 0.27-0.81). In postmenopausal women, obesity turned out to be an important modifier of the association between cigarette smoking and the risk of endometrial cancer. This finding calls for caution in interpreting the favorable effects of cigarette smoking, considering the toxic and carcinogenic effects of tobacco.
authors.affiliation: SOC Epidemiologia e Biostatistica, Centro di Riferimento Oncologico, IRCCS, Aviano, Italy.
authors.forename: Jerry
authors.initials: J
authors.lastname: Polesel
authors.forename: Diego
authors.initials: D
authors.lastname: Serraino
authors.forename: Antonella
authors.initials: A
authors.lastname: Zucchetto
authors.forename: Ersilia
authors.initials: E
authors.lastname: Lucenteforte
authors.forename: Luigino
authors.initials: L
authors.lastname: Dal Maso
authors.forename: Fabio
authors.initials: F
authors.lastname: Levi
authors.forename: Eva
authors.initials: E
authors.lastname: Negri
authors.forename: Maurizio
authors.initials: M
authors.lastname: Montella
authors.forename: Silvia
authors.initials: S
authors.lastname: Franceschi
authors.forename: Renato
authors.initials: R
authors.lastname: Talamini
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D016889:Endometrial Neoplasms / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008572:Menarche; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D013557:Switzerland / Q000453:epidemiology; D055815:Young Adult