Serum concentrations of insulin-like growth factor-I, insulin-like growth factor binding protein-3 and cardiovascular risk factors in adolescents

Abstract

The risk association between the insulin like growth factor-I (IGF-I) system and cardiovascular risk is inconclusive in adults and under-explored in adolescents. We aimed to investigate the associations between serum concentrations of IGF-I and IGF binding protein-3 (IGFBP-3) and cardiovascular risk factors in adolescents. This was a cross-sectional, population-based, observational study in a school setting with 2102 Hong Kong Chinese adolescents aged 12-19 years. Serum IGF-I and IGFBP-3 concentrations were measured by chemiluminescence immunoassays. Anthropometric indices and traditional cardiovascular risk factors were assessed. After excluding participants with abnormal thyroid and liver test results, 765 boys and 877 girls, mean (±SD) age of 15.3 (±2.0) and 15.7 (±2.0) years, respectively, were included in the analysis. Multivariable regression analyses revealed that both IGF-I and IGFBP-3 concentrations were independently associated with waist circumference, fasting insulin and haemoglobin concentrations in boys (all P < 0.05), systolic blood pressure, serum creatinine, fasting insulin and haemoglobin concentrations in girls (all P < 0.05). In girls, IGF-I was also associated with C-reactive protein concentration (P < 0.001) and IGFBP-3 was associated with fasting triglyceride concentration (P < 0.001). Compared with adolescents with the lowest tertile, the top tertile of both IGF-I and IGFBP-3 concentrations were associated with increased odds of having overweight/obesity, top tertiles of insulin and haemoglobin in both boys and girls (P for trend, all <0.05). The associations between serum IGF-I, IGFBP-3, obesity, cardiovascular risk factors, insulin and haemoglobin suggest that dysregulation of the IGF system may play a linking role for the clustering of cardiovascular risk factors.