Abstract 2467: Carboxy-terminal Pro-Vasopressin is a Marker of Insulin Resistance and Metabolic Syndrome in Adults with Hypertension
In addition to its vasoconstrictor and antidiuretic properties, Vasopressin plays a role in activating the hypothalamic-pituitary-adrenal axis. We hypothesized that in adults with hypertension, vasopressin would be associated with metabolic syndrome (MetSyn) and measures of insulin resistance. Participants included 1034 African Americans (AA) (65±9 y, 73 % women) and 877 non-Hispanic whites (NHW) (61±9 y, 56% women) belonging to hypertensive sibships. Because plasma AVP has a short half-life, we measured C-terminal pro-vasopressin (CT-proAVP) by an immunoluminometric assay. MetSyn was defined based on NCEP III criteria. Generalized estimating equations were used to assess whether CT-proAVP was associated with MetSyn independent of confounding variables. The prevalence of MetSyn was 57% in AA and 59% in NHW. In both ethnic groups, after adjustment for age and sex, plasma CT-proAVP levels correlated with body mass index (BMI) (P <0.0001), waist circumference (P <0.0001), fasting plasma glucose (P =0.0002) and insulin (P =0.0001), homeostasis model assessment-insulin resistance (HOMA-IR) (P <0.0001), triglycerides (P=0.02), and (inversely) with HDL cholesterol (P =0.04). In multivariate logistic regression models, after adjustment for age, sex, serum creatinine, smoking, statin and aspirin use, history of MI or stroke, and physical activity, CT-proAVP in the highest quartile was associated with an increased odds ratio (OR) of having MetSyn compared to the bottom quartile: OR (95% CI) in AA, 2.0 (1.3–2.9) (P =0.0006); in NHW, 1.6 (1.0 –2.4) (P =0.036). CT-proAVP levels (adjusted for age and sex) increased with increasing number of MetSyn components (P <0.0001 in both ethnic groups). Plasma CT-proAVP is associated with MetSyn and related variables including BMI, waist circumference, fasting plasma glucose and insulin, and HOMA-IR. Our finding indicate that vasopressin plays a role in the pathophysiology of MetSyn in adults with hypertension.