Insulin-like growth factor binding protein-1 as a marker of the metabolic syndrome--a study in borderline hypertension

To evaluate insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein-1 (IGFBP-1) in borderline hypertension (BHT) in relation to plasma lipoprotein and insulin levels, anthropometric variables and 24-h ambulatory blood pressure (BP). Seventy-five BHT men diastolic BP (DBP) 85-94 mmHg) and 75 age-matched normotensive controls (NT, DBP < or = 80 mmHg) were recruited from a population-based screening program.

There was no difference in IGF-I or IGFBP-1 between BHT and NT men. However, subjects with insulin resistance (IR) had decreased levels of IGF-1 (145 +/- 36 vs 153 +/- 28 microg/L, p < 0.05) and IGFBP-1 (41 +/- 15 vs 52 +/- 20 microg/L, p < 0.01) compared to those without IR. IGF-I correlated inversely to BP levels in the BHT group (r = -0.24 to -0.28, p < 0.05). IGFBP-1 correlated inversely with BMI, lipoprotein and insulin levels (r = -0.29 to -0.48, p < 0.01), independent of IR.

While there are no differences between BHT and NT men in IGF-I and IGFBP-1, both are significantly decreased in IR subjects. IGFBP-1 exhibits a close correlation to metabolic factors. Decreased IGFBP-1 could thus be suggested as a variable marking the "metabolic syndrome" of hypertension.