Relationships between serum IGF1 levels, blood pressure, and glucose tolerance: an observational, exploratory study in 404 subjects

Background: In the general population, low IGF1 has been associated with higher prevalence of cardiovascular disease and mortality. Objective: To investigate the relationships between IGF1 levels, blood pressure (BP), and glucose tolerance (GT). Subjects: Four-hundred and four subjects (200 men aged 18-80 years). Exclusion criteria; personal history pituitary or cardiovascular disease; previous and current treatments with drugs interfering with BP, GT, or lipids, corticosteroids (> 2 weeks), estrogen, or testosterone (> 12 weeks); smoking of > 15 cigarettes/day and alcohol abuse (> 3 glasses of wine/day). Results: Two hundred and ninety-six had normal BP (73.3%), 86 had mild (21.3%), and 22 had severe 15.4%) hypertension; 322 had normal GT (NGT (79.7%)), 53 had impaired glucose tolerance (IGT (13.1%)), 29 had diabetes mellitus (7.2%). Normotensive subjects had significantly higher IGF1 levels (0.11 +/- 0.94 SDS) than those with mild (-0.62 +/- 1.16 SDS, P < 0.0001) or severe (-1.01 +/- 1.07 SDS, P < 0.0001) hypertension. IGF1 SDS (t = -3.41, P = 0.001) independently predicated systolic and diastolic BP (t = -2.77, P = 0.006) values. NGT subjects had significantly higher IGF1 levels (0.13 +/- 0.90 SDS) than those with IGT (-0.86 +/- 1.14 SDS, P < 0.0001) or diabetes mellitus (-1.31 +/- 1.13 SDS, P < 0.0001). IGF1 SDS independently predicted fasting glucose (t = -3.49, P = 0.0005) and homeostatic model assessment (HOMA)-R (t = -2.15, P = 0.033) but not insulin (t = -1.92, P = 0.055) and HOMA-beta (t = -0.19, P = 0.85). Conclusion: IGF1 levels in the low normal range are associated with hypertension and diabetes in subjects without pituitary and cardiovascular diseases.