Adiponectin, a hormone secreted by adipocytes, has insulin-sensitizing, antidiabetic, antiinflammatory, and antiangiogenic properties. The authors conducted a nested case-control study in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort, a cohort of male Finnish smokers aged 50-69 years at baseline, to test whether prediagnostic adiponectin concentrations are associated with pancreatic cancer. Between January 1985 and October 2004, 311 incident exocrine pancreatic cancer cases were diagnosed among cohort participants with serum samples. Controls (n = 510) were alive and free of cancer at the time the case was diagnosed and were matched to the cases by age and date of blood drawing. The authors used conditional logistic regression adjusted for smoking, blood pressure, and C-peptide level to calculate odds ratios and 95% confidence intervals for pancreatic cancer. Higher adiponectin concentrations were inversely associated with pancreatic cancer (for highest quintile (> 9.8 microg/mL) vs. lowest (< or =4.6 microg/mL), odds ratio = 0.65, 95% confidence interval: 0.39, 1.07; P-trend = 0.04). The inverse association was significant among cases diagnosed 5 or more years after blood collection (n = 238) (for highest quintile vs. lowest, odds ratio = 0.55, 95% confidence interval: 0.31, 0.98; P-trend = 0.03). These results support the hypothesis that higher adiponectin concentrations may be inversely associated with the development of pancreatic cancer.