# Associations of insulin-like growth factor 1 and IGF binding proteins 2 and 3 with lipids in toddlers

## TL;DR

This study explores how insulin-like growth factor and its binding proteins relate to lipid levels in toddlers, finding only weak associations.

## Contribution

The study provides new insights into the relationship between the IGF axis and lipid profiles in healthy toddlers.

## Key findings

- IGF-1 and IGFBP-3 were weakly positively associated with LDL-C, HDL-C, and TC.
- IGFBP-2 was weakly negatively associated with LDL-C, HDL-C, and TC.

## Abstract

The insulin-like growth factor (IGF) axis is postulated to influence early-life adipocyte activity and lipolysis. We investigated whether IGF-1 and IGF-binding proteins (IGFBP-2, IGFBP-3) are associated with the lipids of healthy toddlers.

Data were collected during the Toddler Milk Intervention trial to test the effect of milk protein on growth in the second year of life in Germany and Spain. Any blood values for IGF-1, IGFBP-2, IGFBP-3, low- and high-density lipoprotein cholesterol (LDL-C, HDL-C), total cholesterol (TC) and triglycerides (TG) were available at 12 and 24 months from 881 to 775 toddlers, respectively. These blood parameters were available from 444 children at both time points. Mixed intercept linear models adjusted for sex, fasting duration, country, and body mass index (BMI) were used to assess the associations between the IGF axis and lipids.

BMI was 17.0 ± 1.4 kg/m2 (M ± SD) at 12 months. IGF-1, IGFBP-3 and IGFBP-2 levels were 75.9 ± 36.1 ng/ml, 2630.3 ± 638.4 ng/ml and 575.5 ± 245.6 ng/ml, respectively; the mean LDL-C, HDL-C, TC and TG levels were 80.5 ± 22.9 mg/dl, 42.2 ± 10.9 mg/dl, 141.7 ± 25.5 mg/dl and 101.2 ± 58.9 mg/dl, respectively. While the IGFBP-2 and TG levels were higher at 12 months (p < 0.001) compared to 24 months, all other parameters were lower (p < 0.05). IGF-1 and IGFBP-3 were weakly positively associated with LDL-C, HDL-C and TC, whereas IGFBP-2 was weakly negatively associated with LDL-C, HDL-C and TC.

The IGF axis is weakly associated with circulating lipids. IGF-1 and its binding proteins seem to have a limited impact on lipid profiles of toddlers.

Clinical trial registration number: NCT02907502, 26.04.2016.

The online version contains supplementary material available at 10.1186/s12944-026-02872-y.