A 25-Year Prospective Study of Plasma Adiponectin and Leptin Concentrations and Prostate Cancer Risk and Survival

BACKGROUND: Adipocytokines may mediate the association between adiposity and lethal prostate cancer outcomes. METHODS: In the Physicians' Health Study, we prospectively examined the association of prediagnostic plasma concentrations of adiponectin and leptin with risk of developing incident prostate cancer (654 cases diagnosed 1982-2000 and 644 age-matched controls) and, among cases, risk of dying from prostate cancer by 2007. RESULTS: Adiponectin concentrations were not associated with risk of overall prostate cancer. However, men with higher adiponectin concentrations had lower risk of developing high-grade or lethal cancer (metastatic or fatal disease). The relative risk (95% CI) comparing the highest quintile to the lowest (Q5 vs Q1) was 0.25 (95% Cl 0.07-0.87; P-trend = 0.02) for lethal cancer. Among all the cases, higher adiponectin concentrations predicted lower prostate cancer-specific mortality [hazard ratio (HR)(Q5 vs Q1) = 0.39; 95% Cl 0.17-0.85; P-trend = 0.02], independent of body mass index (BMI), plasma C-peptide (a marker of insulin secretion), leptin, clinical stage, and tumor grade. This inverse association was apparent mainly among men with a BMI >= 25 kg/m(2) (HRQ5 vs Q1 = 0.10; 95% CI 0.01-0.78; P-trend = 0.02), but not among men of normal weight (P-trend = 0.51). Although the correlation of leptin concentrations with BMI (r = 0.58, P < 0.001) was stronger than that of adiponectin (r = -0.17, P < 0.001), leptin was unrelated to prostate cancer risk or mortality. CONCLUSIONS: Higher prediagnostic adiponectin (but not leptin) concentrations predispose men to a lower risk of developing high-grade prostate cancer and a lower risk of subsequently dying from the cancer, suggesting a mechanistic link between obesity and poor prostate cancer outcome. (C) 2009 American Association for Clinical Chemistry