Serum insulin-like growth factor I and its binding protein 3 in their relation to intima-media thickness: results of the study of health in Pomerania (SHIP)

Objective Previous studies detected associations between lower insulin-like growth factor I (IGF-I) levels and increased risk of congestive heart failure or ischaemic heart disease. The aim of the present study was to assess the association of IGF-I and its binding protein 3 (IGFBP-3) with the carotid intima-media thickness (IMT) as marker of asymptomatic cardiovascular disease. Design and population From the population-based Study of Health in Pomerania (SHIP), a total of 2286 participants aged 45 years or older with readable ultrasound of the carotid arteries were available for the present analyses. Methods and measurements Serum IGF-I and IGFBP-3 levels were categorized into three groups (low, moderate, high) according to the sex-specific 10th and 90th percentile. Analyses of variance (ANOVA) and logistic regression analyses adjusted for age, waist circumference, diabetes, hypertension and creatinine clearance were performed. Results After adjusting for confounding factors, IGF-I and the IGF-I/IGFBP-3 ratio were positively related to IMT in ANOVA. Logistic regression analyses confirmed these findings and showed that high IGF-I levels, a high IGF-I/IGFBP-3 ratio and low IGFBP-3 levels were associated to higher odds of increased IMT. Conclusion In conclusion, high IGF-I or high IGF-I/IGFBP-3 ratio values and low IGFBP-3 levels are associated with increased IMT. Therefore, systemic levels of the IGF axis or alterations in the balance of its components are associated with subclinical atherosclerotic disease.