SIRT1 Polymorphisms and Serum-Induced SIRT1 Protein Expression in Aging and Frailty: The CHAMP Study.

The nutrient sensing protein, SIRT1 influences aging and nutritional interventions such as caloric restriction in animals, however, the role of SIRT1 in human aging remains unclear. Here, the role of SIRT1 single-nucleotide polymorphisms (SNPs) and serum-induced SIRT1 protein expression (a novel assay that detects circulating factors that influence SIRT1 expression in vitro) were studied in the Concord Health and Ageing in Men Project (CHAMP), a prospective cohort of community dwelling men aged 70 years and older. Serum-induced SIRT1 expression was not associated with age or mortality, however participants within the lowest quintile were less likely to be frail (odds ratio (OR) 0.34, 95% confidence interval (CI) 0.17-0.69, N = 1,309). Serum-induced SIRT1 expression was associated with some markers of body composition and nutrition (height, weight, body fat and lean % mass, albumin, and cholesterol) but not disease. SIRT1 SNPs rs2273773, rs3740051, and rs3758391 showed no association with age, frailty, or mortality but were associated with weight, height, body fat and lean, and albumin levels. There were some weak associations between SIRT1 SNPs and arthritis, heart attack, deafness, and cognitive impairment. There was no association between SIRT1 SNPs and the serum-induced SIRT1 assay. SIRT1 SNPs and serum-induced SIRT1 expression in older men may be more closely associated with nutrition and body composition than aging and age-related conditions.