Circulating levels of insulin-like-growth factor binding protein (IGFBP-1) in relation to insulin resistance, type 2 diabetes and metabolic syndrome (CURES - 118)

The objective was to assess the association of insulin-like growth factor binding protein-1 (IGFBP-1) with insulin resistance (IR), type 2 diabetes mellitus (T2DM), and metabolic syndrome (MS) in Asian Indians. Fifty subjects with normal glucose tolerance (NGT) and 50 with T2DM were randomly selected from the Chennai Urban Rural Epidemiology Study. Insulin-like growth factor binding protein-1 was measured by sandwich enzyme-linked immunosorbent assay. Serum insulin was estimated using Dako (Glostrup, Denmark) kits. Insulin resistance was calculated using the homeostasis model assessment. Subjects with T2DM had significantly decreased levels of IGFBP-1 (21.7 ± 3.5 ng/mL) compared with NGT subjects (34.4 ± 7.6 ng/mL, P < .001). The IGFBP-1 was significantly lower in NGT subjects with IR as measured by the homeostasis model assessment (25.5 ± 6.5 ng/mL) compared with NGT subjects without IR (40.7 ± 9.5 ng/mL, P < .001). On regression analysis, IR showed a significant association with IGFBP-1 even after adjusting for age, sex, body mass index, and glycated hemoglobin (β = -3.714, P < .001). Type 2 diabetes mellitus was significantly associated with IGFBP-1 even after adjusting for age, sex, and body mass index (β = -12.798, P < .001). The IGFBP-1 levels decreased with increasing number of metabolic abnormalities (P for trend < .001). Logistic regression analysis showed that IGFBP-1 had a strong negative association with MS even after adjusting for age and sex (odds ratio, 0.942; 95% confidence interval, 0.914-0.971; P < .001). Among Asian Indians, lower levels of circulating IGFBP-1 are seen in subjects with IR, T2DM, and MS