title: Plasma fetuin-A concentrations in young and older high- and low-active men.
abstract: Fetuin-A is a liver-derived factor that may play a role in insulin resistance and age-related chronic diseases (eg, type 2 diabetes mellitus and cardiovascular [CV] disease). Regular exercise improves CV risk and insulin sensitivity; however, it is unknown whether chronic exercise training is related to circulating levels of fetuin-A. Therefore, this study examined whether plasma fetuin-A levels were related to age and chronic physical activity in men. We hypothesized that chronic physical activity would be related to lower plasma fetuin-A levels in younger and older men. In healthy high-active (HI) and low-active (LO) young (HI, n = 7; LO, n = 8) and older (HI, n = 12, LO, n = 11) men, we determined cardiorespiratory fitness (maximal oxygen uptake), plasma fetuin-A levels, plasma insulin, insulin resistance (homeostasis model assessment of insulin resistance), and the standard risk factors for CV disease. Groups were matched for body mass index. Fetuin-A was significantly higher (~20%) in both young and older LO men compared with their HI counterparts, and fetuin-A was inversely related to maximal oxygen uptake (r = -0.40, P = .014). Plasma fetuin-A levels showed trends to be significantly correlated with insulin (r = -0.34, P = .052) and homeostasis model assessment of insulin resistance (r = 0.33, P = .058) in the older individuals. In younger participants, fetuin-A was related to blood pressure and cholesterol measures. These results indicate that low levels of fetuin-A are related to cardiorespiratory fitness and a number of conventional CV and metabolic disease risk factors independent of age and body mass index. Therefore, the maintenance of low levels of circulating fetuin-A may be a novel mechanism contributing to enhanced insulin sensitivity with regular physical activity.
authors.affiliation: Department of Kinesiology, School of Public Health, University of Maryland College Park, MD 20742, USA.
authors.forename: Nathan T
authors.initials: NT
authors.lastname: Jenkins
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: McKenzie
authors.forename: James M
authors.initials: JM
authors.lastname: Hagberg
authors.forename: Sarah
authors.initials: S
authors.lastname: Witkowski
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000502:physiology; D001798:Blood Proteins / Q000032:analysis / Q000378:metabolism*; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000503:physiopathology; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology; D012307:Risk Factors; D055815:Young Adult; D060749:alpha-2-HS-Glycoprotein
chemical_list: C556354:AHSG protein, human; D001786:Blood Glucose; D001798:Blood Proteins; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D007328:Insulin; D060749:alpha-2-HS-Glycoprotein; D002784:Cholesterol