Normative data for insulin-like growth factor-1 and insulin-like growth factor binding protein-3 and their determinants in healthy adult males from india: the INDIIGo study

The INDIIGo study aimed to establish normative data for serum insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) in adult Indian males, addressing the paucity of data for the South East Asian population. This cross-sectional study included 1271 healthy males aged 20 to 65.9 years from Chandigarh, India, with measurements obtained using the Roche Elecsys electrochemiluminescence immunoassay (ECLIA). Age-specific normative centile curves were generated using the LMS (Lambda, Mu, Sigma) method. Serum IGF-1 levels declined by 30.1 ng/ml per decade (95% CI - 34.9 to - 25.2; p < 0.001) and were negatively associated with lower socioeconomic status (- 5.8 ng/ml per class; p = 0.002), ALT (- 0.6 ng/ml per unit; p < 0.001), and HbA1c (- 8.2 ng/ml per category; p = 0.04). Positive correlations were observed with serum T4 (+ 4.5 ng/ml per unit; p < 0.001) and serum albumin (+ 18.0 ng/ml per g/dL; p = 0.009). IGFBP-3 levels decreased by 447.8 ng/ml per decade (95% CI - 547.6 to - 348.1; p < 0.001), with a significant positive association with serum T4 (+ 60.8 ng/ml per unit; p = 0.025). This study provides age-specific normative data for IGF-1 and IGFBP-3 in Indian males and identifies key factors influencing these biomarkers.