Association between adiponectin, insulin resistance, and endometrial cancer

BACKGROUND. Obesity is a well known risk factor for the development of endometrial cancer; however, weight alone does not account for all cases. The authors hypothesized that insulin resistance also contributes to an increased risk for endometrial cancer. Adiponectin is a protein secreted by adipose cells and has been shown to be a surrogate marker for insulin resistance, with low levels of adiponectin correlated with hyperinsulinemia and degree of insulin resistance. The purpose of the current study was to determine whether there was an independent association between adiponectin level and endometrial cancer. METHODS. A case-control study was performed on 117 endometrial cancer patients (cases) and 238 women with no history of cancer (controls). Serum adiponectin levels were measured using enzyme-linked immunoadsorbent assay and examined for their association with endometrial cancer. Univariate and multivariate logistic regression analyses were performed with adjustment for confounding factors. RESULTS. The mean serum adiponectin levels were significantly lower among cases (88.8 +/- 63.3 ng/mL) than among controls (148.2 +/- 68.3; P <.001). This inverse correlation continued to be observed after controlling for age, body mass index, diabetes, and hypertension. Cases were significantly more likely to have serum adiponectin levels in the lowest (odds ratio [OR] of 10.5; 95% confidence interval [95% CI], 4.49-24.57 [P <.001]) and intermediate tertiles (OR of 2.5; 95% Cl, 1.01-6.21 [P =.05]) when compared with controls. CONCLUSIONS. Adiponectin level was found to be independently and inversely associated with endometrial cancer. Women with endometrial cancer were more likely to have low adiponectin levels than controls, even after adjusting for body mass index. This suggested that insulin resistance is independently associated with endometrial cancer.