Longitudinal association between IGFBP-1 levels and parameters of the metabolic syndrome in obese children before and after weight loss

Abstract

Background. Insulin-like growth factor binding protein 1 (IGFBP-1) is a marker of insulin resistance. We hypothesized that IGFBP-1 is associated with the metabolic syndrome (MetS), which is related to insulin resistance. Methods. We examined 51 obese Caucasian children (mean age 12.1 ± 2.3, 55% male, mean body mass index [BMI] 31.8 ± 4.8 kg/m²). Anthropometrical markers, pubertal stage, hepatic ultrasound, waist circumference, blood pressure, fasting serum IGFBP-1, IGFBP-3, IGF-I, adiponectin, leptin, transaminases, glucose, insulin, triglycerides, and HDL-cholesterol concentrations were determined at onset and the end of the one-year lifestyle intervention. Results. In contrast to IGF-I and IGFBP-3, IGFBP-1 correlated significantly to most parameters of the MetS in cross-sectional (waist circumference: r = −0.45, triglycerides: r = −0.29; insulin: r = −0.31; HOMA: r = –0.30) and longitudinal analyses (Δ triglycerides: r = −0.22; Δ Insulin: r = −0.25; Δ HOMA: r = −0.62). The association between changes of HOMA and changes of IGFBP-1 was stronger than the associations between changes of leptin or adiponectin, and changes of HOMA. The risk for the MetS was inversely related to IGFBP-1 levels (odds ratio: −0.05 per additional IGFBP-1 unit; 95% confidence interval: −0.08 up to −0.02; p = 0.019) in a multiple logistic regression analyses adjusted to BMI, pubertal stage, age, and gender. The nine obese children with the MetS had significantly lower IGFBP-1 levels (1.6 ± 1.3 ngm/l) than the 42 obese children without the MetS (4.0 ± 3.8 ng/ml). The eleven obese children with fatty liver assessed by ultrasound had significantly lower IGFBP-1 levels (1.5 ± 1.3 ngm/l) than the 40 obese children without fatty liver (4.2 ± 4.1 ng/ml). Conclusion. The strong relationships between IGFBP-1, insulin resistance, and the MetS suggest that IGFBP-1 might be a promising marker for these entities in obesity.

This study is registered at clinicaltrials.gov (NCT00435734).

Key words::

• IGFBP-1
• insulin
• triglycerides
• obesity
• children
• weight loss
• insulin resistance
• metabolic syndrome
• blood pressure
• HDL-cholesterol
• fatty liver

Acknowledgements

We thank Ms. K. Schark-Zimmer, Children's Hospital University of Bonn, for her kind support in the laboratory and Gideon des Sousa for reviewing the paper as a native English speaker.

Disclosure summary

TR: received grant support (2008–2010) from the German Ministry of Education and Research (Bundesministerium für Bildung und Forschung Obesity network: LARGE, grant number 01 GI0839, the National Genome Research Network, NGFNplus [01GS0820]) and from Merck/Serono.

MK: received grant support from the University of Witten/Herdecke.

CR: received grant support (2003–2004) from the Bonfor Research Foundation, University of Bonn, Germany.

AMT: was partly supported by the Munich Center of Health Sciences (LMUinnovativ) subproject II “Evidence Based Prevention and Modelling of Chronic Diseases” and the German Ministry of Education and Research (Bundesministerium für Bildung und Forschung Obesity network: LARGE, grant number 01 GI0839). However, the hypo-thesis development, analysis, interpretation and conclusions contained.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.