IGF1 and its binding proteins 3 and 1 are differentially associated with metabolic syndrome in older men

Copyright © 2010 by European Society of EndocrinologyObjective: Circulating IGF1 declines with age, and reduced circulating IGF1 is associated with increased cardiovascular mortality in some but not all studies. The relationship between IGF-binding proteins 3 and 1 (IGFBP3 and IGFBP1) with risk of cardiovascular disease remains unclear. We sought to examine associations between IGF1, IGFBP3 and IGFBP1 with metabolic syndrome in older men. Design: Cross-sectional analysis of 3980 community-dwelling men aged 70 years. Methods: Morning plasma levels of IGF1, IGFBP3 and IGFBP1 were assayed. Metabolic syndrome was defined according to National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) criteria. Results: For IGF1 and IGFBP3, there was a U-shaped relationship, with middle quintiles possessing the lowest odds ratios (OR) for metabolic syndrome (reference Q1, Q3 IGF1: OR 0.74, 95% confidence intervals 0.57–0.96, Q3 IGFBP3: OR 0.67, 0.51–0.87). Increasing IGFBP1 was associated with reduced risk of metabolic syndrome with a dose–response gradient (reference Q1, OR for Q2 to Q5 IGFBP1: 0.56, 0.33, 0.22 and 0.12 respectively, P