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 of pituitary or cardiovascular diseases; previous or current treatments with drugs interfering with BP, GT, or lipids, corticosteroids (>2 weeks), estrogens, 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 (5.4%) 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 predicted 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.