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.

Endometrial cancer and the IGF system: a case-control study in Greece.

OBJECTIVES: Insulin-like growth factor I (IGF-I) and other components of the IGF system have been implicated in the etiology of several human malignancies. We have undertaken a case-control study among Greek women to explore the relation of major components of the IGF system (IGF-I, IGF-II and IGF-binding protein 3, IGFBP-3) with endometrial cancer risk. METHODS: During a 1-year period (1999), 84 incident cases of histologically confirmed endometrial cancer were compared with 84 control women admitted to the same clinical department for small gynecological operations, mainly pelvic prolapse. Data were modeled through multiple logistic regression. RESULTS: Endometrial cancer was positively associated with IGF-II and inversely with IGF-I. Both associations were statistically significant and they appear symmetrical around the null value. IGFBP-3 is positively associated with endometrial cancer risk, but this association does not reach statistical significance. CONCLUSIONS: This study adds to the gradually developing consensus that components of the IGF system play a central role in human carcinogenesis. It is possible that IGF-II, rather than IGF-I, is closely linked to the etiology of endometrial cancer, the form of cancer most strongly associated with obesity.

Leptin and body mass index in relation to endometrial cancer risk.

BACKGROUND/AIM: Because leptin is a hormone associated with obesity and reproduction, we attempted to examine whether there is a relationship between leptin and endometrial cancer. METHODS: Cases were 84 women with histologically confirmed incident endometrial cancer, whereas controls were 84 women admitted to the same hospital for small surgical operations. The serum leptin levels were determined in fasting morning blood samples by using radioimmunoassay. The mean values of leptin levels among cases and controls were compared with simple t test, and the data were further analyzed using multiple logistic regression procedures. RESULTS: The serum leptin levels were 36.7 +/- (SD) 25.7 ng/ml among cases and 26.9 +/- 19.8 ng/ml among controls (p = 0.006). After adjustment for known risk factors of endometrial cancer, components of the insulin-like growth factor system did not confound the association of leptin with endometrial cancer, but this association was eliminated, when the body mass index was adjusted for. Thus, the odds ratio for an increment of 1 SD of blood leptin was 1.52 (p = 0.03) before adjustment for body mass index, but only 1.13 (p = 0.62) after adjustment for it. CONCLUSIONS: In a case-control study of incident endometrial cancer in Greece, we found evidence that leptin is strongly positively associated with endometrial cancer. It cannot be conclusively inferred, however, whether leptin elevation, as a consequence of obesity, plays a role in endometrial carcinogenesis or whether it is a simple correlate of obesity.

Diet in relation to endometrial cancer risk: a case-control study in Greece.

The risk of endometrial cancer is positively associated with obesity, but the role of specific nutrients remains unclear. Given the distinct characteristics of the Greek diet and the low incidence of this form of cancer among Greek women, we undertook a case-control study to investigate the association of endometrial cancer with food groups and micronutrients. Cases were 84 women with histologically confirmed endometrial cancer and controls were 84 women with intact uterus admitted to the same teaching hospital in Athens, Greece. Consumption of pulses, nuts, and seeds was significantly inversely related to the risk for endometrial cancer. No other significant association with food groups was detected, although a protective effect of added lipids, which in the Greek diet are primarily represented by olive oil, was highly suggestive. Retinol, nicotinic acid, vitamin B- 6, and riboflavin were inversely associated with the disease. These findings need to be replicated, because this was a relatively small study with the statistical power to detect only strong associations between cases and controls; they appear, however, to support a role of diet in the etiology of endometrial cancer.