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) mmol/L and 113.4 (31.2) ng/mL, respectively. After adjustment for age and sex, selenium levels were positively associated with total IGF-1 (b SE: 43.76 11.2, p ¼ 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 (b SE: 36.7 12.2, p ¼ 0.003). The association was still significant when IL-6 was introduced in the model (b SE: 40.1 12.0, p ¼ 0.0008). Conclusions: We found an independent, positive and significant association between selenium and IGF-1 serum levels in community dwelling older adults.