Association of plasma selenium concentrations with total IGF-1 among older community-dwelling adults: The InCHIANTI study

Background & aims: Insulin-like growth factor (IGF-1) stimulates cell proliferation and inhibits cell apoptosis. Recent studies underline its importance as anabolic hormone and nutritional marker in older individuals. IGF-1 synthesis and bioactivity are modulated by nutritional factors including selenium intake. However, whether circulating IGF-1 levels are positively influenced by plasma selenium, one of the most important human antioxidants, is still unknown. Methods: Selenium and total IGF-1 were measured in 951 men and women >= 65 years from the InCHIANTI study, Tuscany, Italy. Results: Means (SD) of plasma selenium and total IGF-1 were 0.95 (0.15) mu mol/L and 113.4 (31.2) ng/mL, respectively. After adjustment for age and sex, selenium levels were positively associated with total IGF-1 (13 SE: 43.76 +/- 11.2, p = 0.0001). After further adjustment for total energy and alcohol intake, serum alanine aminotransferase (ALT), congestive heart failure, selenium remained significantly associated with IGF-1 (beta +/- SE: 36.7 +/- 12.2, p = 0.003). The association was still significant when IL-6 was introduced in the model (beta +/- SE: 40.1 +/- 12.0, p = 0.0008). Conclusions: We found an independent, positive and significant association between selenium and IGF-1 serum levels in community dwelling older adults. (C) 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.