title: Intra-individual variation of plasma adipokine levels and utility of single measurement of these biomarkers in population-based studies.
abstract: Adipokines, soluble mediators produced by adipocytes, may link adipose tissue to the inflammatory, metabolic, and immune dysregulation that characterize many obesity-related diseases. The stability of plasma adipokine levels within individuals, their seasonal variability, intercorrelations, and relationships to well-established measures of adiposity are incompletely defined. We measured levels of 12 adipokines [interleukin 1beta (IL-1beta), IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha), plasminogen activator inhibitor-1 (PAI-1), high-sensitivity C-reactive protein (hsCRP), monocyte chemoattractant protein-1 (MCP-1), nerve growth factor (NGF), leptin, adiponectin, hepatocyte growth factor (HGF), and resistin] in four seasonal random plasma samples of 48 male participants of a population-based cohort study. The representativeness of single measurements was assessed by correlating the adipokine levels of a single, random sample with the mean levels from the remaining three samples using a bootstrap approach and using intra-class correlation coefficients (ICC). Spearman correlations between adipokine levels, age, body mass index (BMI), and waist-to-hip ratio (WHR) were estimated. Correlations between plasma adipokine levels from one random sample and the mean of the remaining three seasonal samples ranged from 0.57 to 0.89. Over the 1-year study period, the ICCs for adipokine levels ranged from 0.44 (PAI-1) to 0.83 (HGF). IL-8, MCP-1, and resistin levels were positively associated with age; HGF and PAI-1 levels were correlated with BMI and WHR. This study suggests that adipokine levels in a single blood sample may be useful biomarkers of inflammation in population-based studies of obesity-related disease.
authors.affiliation: Vanderbilt Epidemiology Center, Nashville, Tennessee 37203-1738, USA.
authors.forename: Sang-Ah
authors.initials: SA
authors.lastname: Lee
authors.forename: Asha
authors.initials: A
authors.lastname: Kallianpur
authors.forename: Yong-Bing
authors.initials: YB
authors.lastname: Xiang
authors.forename: Wanqing
authors.initials: W
authors.lastname: Wen
authors.forename: Qiuyin
authors.initials: Q
authors.lastname: Cai
authors.forename: Dake
authors.initials: D
authors.lastname: Liu
authors.forename: Sergio
authors.initials: S
authors.lastname: Fazio
authors.forename: MacRae F
authors.initials: MF
authors.lastname: Linton
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Xiao Ou
authors.initials: XO
authors.lastname: Shu
mesh_terms: D054392:Adipokines / Q000097:blood*; D050154:Adiposity / Q000502:physiology; D015992:Body Mass Index; D015331:Cohort Studies; D006801:Humans; D007249:Inflammation / Q000097:blood; D008297:Male; D008875:Middle Aged; D012621:Seasons
chemical_list: D054392:Adipokines