Plasma carboxy-terminal provasopressin (copeptin): a novel marker of insulin resistance and metabolic syndrome.
BACKGROUND
Stress-mediated hypothalamic-pituitary-adrenal axis activation, regulated by arginine vasopressin (AVP), may have a role in the pathophysiology of metabolic syndrome (MetSyn).


OBJECTIVE
The objective of the study was to investigate whether plasma C-terminal provasopressin fragment (copeptin), a surrogate for circulating AVP, was associated with measures of insulin resistance and presence of MetSyn.


METHODS
This was a multicenter, community-based study, investigating novel biomarkers for vascular disease. Participants included 1293 African-Americans (AA) (64 +/- 9 yr) and 1197 non-Hispanic whites (NHW) (59 +/- 10 yr) belonging to hypertensive sibships.


METHODS
Plasma copeptin levels were measured by an immunoluminometric assay. MetSyn was defined per Adult Treatment Panel III criteria. Generalized estimating equations were used to assess whether plasma copeptin was associated with measures of insulin resistance and MetSyn.


RESULTS
The prevalence of MetSyn was 50% in AA and 49% in NHW. In each group, after adjustment for age and sex, plasma copeptin levels significantly correlated with body mass index, fasting plasma glucose and insulin, homeostasis model assessment of insulin resistance, triglycerides, and (inversely) high-density lipoprotein cholesterol (P < 0.05 for each variable). In multivariable logistic regression models that adjusted for age, sex, smoking, statin use, serum creatinine, education, physical activity, and diuretic use, plasma copeptin levels in the highest quartile were associated with an increased odds ratio of having MetSyn compared with bottom quartile: odds ratio (95% confidence interval) in AA, 2.07 (1.45-2.95); in NHW, 1.74 (1.21-2.5).


CONCLUSIONS
Our findings indicate a novel cross-sectional association between plasma copeptin and measures of insulin resistance and MetSyn.
Saleem
Umer
U
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
Khaleghi
Mahyar
M
Morgenthaler
Nils G
NG
Bergmann
Andreas
A
Struck
Joachim
J
Mosley
Thomas H
TH
Kullo
Iftikhar J
IJ
D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006020:Glycopeptides / Q000097:blood* / Q000502:physiology; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000453:epidemiology / Q000208:ethnology; D008875:Middle Aged; D008954:Models, Biological; D044465:White People / Q000706:statistics & numerical data
D015415:Biomarkers; D006020:Glycopeptides; C048197:copeptins