Plasma adiponectin concentrations in relation to endometrial cancer: a case-control study in Greece

Adiponectin is a hormone secreted exclusively by adipocytes, and obesity is an established risk factor for endometrial cancer. We have, thus, evaluated the association of adiponectin with the occurrence of endometrial cancer. Questionnaire information and blood samples were taken before treatment from 84 women with newly diagnosed, histologically confirmed endometrial cancer and 84 control women who were admitted for minor gynecologic problems, mainly pelvic prolapse. Adiponectin levels were measured by immunoassay. The results were analyzed through multiple logistic regression and controlled for known risk factors for endometrial cancer, leptin, as well as major components of the IGF system (IGF-I, IGF-II, and IGF-binding protein 3). Among control women, there was no significant association of adiponectin with age or parity. Although there was no association of adiponectin with endometrial cancer among women 65 yr or older, there was an inverse, fairly strong, and statistically significant inverse association among younger women. Among women younger than 65 yr, an increase of adiponectin by 1 SD was associated with a more than 50% reduction of the risk for endometrial cancer [odds ratio (OR) 0.44; 95% confidence interval (CI) 0.24-0.81], even after controlling for body mass index and other potential confounders. Among all women, the adjusted OR for a 1 SD increase in adiponectin was not significant (OR, 0.78; 95% CI, 0.56-1.10) but was significant for a one quintile increase in adiponectin (OR, 0.74; 95% CI, 0.56-0.97). In women younger than 65 yr, among whom obesity represents a powerful risk factor for endometrial cancer, adiponectin is inversely and significantly related to the risk of this disease. This association is independent of possible effects of major components of the IGF system, leptin, body mass index, sociodemographic variables, and known endometrial cancer risk factors. Future studies are needed to prove causality and provide insight on both the mechanism of action of this hormone and its potential role in endometrial cancer.