Low levels of adiponectin have been related to coronary heart disease, but adiponectin is higher in persons with type 1 diabetes who have an increased rate of coronary disease. In the Coronary Artery Calcification in Type 1 Diabetes Study (2000-2002), the authors investigated potential determinants of elevated adiponectin levels in persons with type 1 diabetes and whether a difference exists compared with nondiabetic persons. Serum adiponectin was measured in 1,393 persons (sex: 48% male; age: 38 (standard deviation: 9) years; diabetes duration: 23 (standard deviation: 9) years; 54% nondiabetic and 46% with type 1 diabetes). Determinants of log-transformed adiponectin levels were evaluated by multiple linear regression analysis with interaction terms to determine whether predictors of adiponectin levels differed by diabetes status. Adiponectin levels were higher in type 1 diabetic than nondiabetic persons (13.5 (standard deviation: 1.0) vs. 8.8 (standard deviation: 1.0) microg/ml; p < 0.0001), adjusting for age, gender, body mass index, and glomerular filtration rate. The final regression model explained 67% of the difference in adiponectin levels between type 1 diabetic and nondiabetic persons. The variables explaining this difference included high density lipoprotein cholesterol, albumin excretion rate, plasminogen activator inhibitor-1, and hemoglobin A1c level. Adiponectin is higher in type 1 diabetic than nondiabetic persons. Although some of the difference can be explained, further study is needed to better understand the relation between elevated adiponectin levels and patient outcomes, including coronary heart disease.