Serum leptin-adiponectin ratio and endometrial cancer risk in postmenopausal female subjects

Objective. Obesity is a well-known risk factor for the development of endometrial cancer. Elevated endogenous estrogen and insulin resistance are recognized to be major factors that link obesity and cancer development. However, there is increasing evidence that the adipokines adiponectin and leptin, which are directly produced in adipose tissue, impact several obesity-related cancers. The purpose of the current study was to investigate the relationships of the concentration of leptin, adiponectin, and the leptin-to-adiponectin ratio (L/A ratio) with the endometrial cancer risk in postmenopausal female subjects. Methods. A case-control study was performed in 146 postmenopausal female subjects with endometrial cancer and 150 control subjects with no history of cancer. The serum levels of the adipokines leptin and adiponectin were measured, and the associations of these adipokines and the L/A ratios with the endometrial cancer risk were analyzed. Results. The leptin levels and the L/A ratios were significantly higher in the incident cases of endometrial cancer (8.2 +/- 0.5, 2.05 +/- 1.08 ng/ml) than in the controls subjects (4.5 +/- 0.5, 0.98 +/- 0.18, P<0.0001), whereas the adiponectin levels were significantly lower in the incident cases (6.2 +/- 0.4 mu g/ml) than in the control subjects (9.0 +/- 0.4 mu g/ml, P<0.0001). For the incident cases, the serum levels of the adipokines were significantly correlated with the patient body mass index (BMI) (P<0.001 for leptin, P<0.05 for adiponectin), and the leptin levels and the L/A ratios were significantly correlated with the homeostasis model assessment ratio (HOMA-R) and the fasting insulin levels (P<.001). Higher L/A ratios were found to be significantly associated with an increased risk of endometrial cancer [OR (95% Cl) for the top vs. the bottom tertile of the L/A ratio was 6.0 (3.2-11.9), P-value<0.0001]. Moreover, the ORs of the L/A ratios were higher than those of leptin or adiponectin alone. The association of the L/A ratios with endometrial cancer risk remained after adjusting for the obesity indices, hypertension, and presence of diabetes mellitus. Conclusion. The present results suggested that the L/A ratio was independently associated with an increased risk for endometrial cancer development. Additional research will elucidate the molecular mechanisms by which these adipokines are associated with the development of endometrial cancer. (C) 2010 Published by Elsevier Inc.