Relationship between circulating visfatin/NAMPT, nutritional status and insulin resistance in an elderly population - results from the PolSenior substudy.

BACKGROUND: Circulating visfatin/nicotinamide phosphoribosyltransferase (visfatin/NAMPT) levels according to some studies are related to nutritional status and insulin resistance. These associations have not been studied in large elderly populations. Therefore, the aim of our study was to assess the relationships between circulating visfatin/NAMPT levels, nutritional status, and insulin resistance in a large population of the elderly. MATERIALS AND METHODS: Concentrations of glucose, albumin, creatinine, CRP, interleukin-6, insulin, and visfatin/NAMPT (by ELISA) were assessed, and HOMA-IR calculated in 3050 elderly participants of the PolSenior study. RESULTS: The highest plasma visfatin/NAMPT levels were observed in obese, as well as in non-diabetic insulin resistant subjects; however there were only significant differences found in women. The regression models showed that plasma visfatin/NAMPT levels decline with age and increased with waist circumference, BMI, and hs-CRP. Waist circumference was better correlated than BMI for visfatin/NAMPT levels in statistical models not adjusted by sex, and just the opposite in models which were. We demonstrated a 0.023ng/mL increase of Visfatin/NAMPT levels for 1mg/L increase of hs-CRP, and a 0.007ng/mL decline for each year of age. CONCLUSION: Our study revealed that in elderly subjects, circulating visfatin/NAMPT levels are related to age, nutritional status, especially visceral obesity, and inflammation.