Abstract B81: Racial differences in serum adiponectin and leptin before and after weight loss

Abstract

Abstract Background: In vitro and in vivo data have shown that adiponectin is antiangiogenic and that leptin increases angiogenesis. The divergent roles that these two adipocytokines play in cancer biology may be underlying mechanisms for racial disparities in cancer severity and mortality. The purpose of this study was to determine whether there were differences in serum concentrations of adiponectin and leptin before and after weight loss in healthy premenopausal African-American (AA) and European-American (EA) women. Methods: Sixty-three African-American (AA) and 58 European-American (EA) premenopausal women were weight-reduced from body mass index (BMI) 27-30 kg/m2 to BMI≤24 kg/m2. Body composition measurements and fasting blood samples were collected before and after weight loss. Repeated-measures mixed models were used to assess the change in adiponectin and leptin from baseline to the weight-reduced state and whether there were racial differences after adjusting for covariates. Results: Following weight loss leptin significantly decreased and adiponectin significantly increased similarly in both racial groups. Mix-model analyses indicated that adiponectin differed with race after adjusting for age, time, intra-abdominal fat, interleukin-6, limb fat and trunk fat (p=0.039). Adjusted least squared means (mean 95% confidence interval) showed that AA women had lower adiponectin relative to EA women at baseline [7.64 (6.8, 8.59) µg/ml vs 9.59 (8.61, 10.7) µg/ml, p=0.011] and in the weight-reduced state [9.84 (8.77, 11.0) µg/ml vs 11.5 (10.3, 12.8) µg/ml, p=0.075]. Mixed-model analyses indicated that leptin differed with race after adjusting for age, time, total fat mass, estradiol, testosterone and insulin (p<.0001). According to the adjusted least squared means, AA women had higher leptin relative to EA women at baseline [25.1 (22.8, 27.7) ng/dl vs 19.6 (18.0, 21.4) ng/dl, p=0.0003] and in the weight-reduced state [12.1 (10.6, 13.7) ng/dl vs 8.23 (7.32, 9.24), p<.0001]. Conclusions: Weight reduction may reduce the risk for cancer severity and mortality through increased serum adiponectin and reduced leptin in both AA and EA women. However, AA women may have worse outcomes as a result of cancer compared to EA women due to differences in the serum concentrations of these adipocyte derived factors that influence tumor angiogenesis. Citation Information: Cancer Prev Res 2010;3(12 Suppl):B81.