Background and Objectives: In adults, discordant associations exist between insulin-like growth factor-I (IGF-I) and blood pressure with scarce reports in apparently healthy children. IGF-I levels increase during puberty in parallel to calcium and phosphorus levels. In this context, our aim is to study the association between IGF-I and blood pressure in apparently healthy children, together with the interaction of the serum calcium-phosphorus product (Ca*P) in this association.
Methods: Subjects were 521 apparently healthy children (age 8.8 ± 0.1) participating in a longitudinal study of cardiovascular risk factors in Spain, of whom 158 were followed-up after 5 years. IGF-I, IGFBP-3, serum calcium and phosphorus were measured at baseline. Anthropometric [body-mass index (BMI) and waist] and cardio-metabolic [systolic (SBP) and diastolic blood pressure, pulse pressure, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), HDL cholesterol and triglycerides] variables were assessed at baseline and at follow-up.
Results: IGF-I and IGF-I/IGFBP-3 molar ratio positively correlated with BMI, waist, SBP, DBP, pulse pressure, insulin, HOMA-IR and triglycerides (r from 0.198 to 0.603; all P<0.01). The strength of the associations with SBP increased with increasing Ca*P at baseline and at follow-up (r from 0.261 to 0.625 for IGF-I; and r from 0.174 to 0.583 for IGF-I/IGFBP-3 molar ratio). After adjusting for confounding variables, IGF-I and IGF-I/IGFBP-3 molar ratio remained independently associated with SBP in children in the highest Ca*P tertile, both at baseline and at follow-up (β from 0.245 to 0.381; P<0.01; model R2 from 0.246 to 0.566).
Conclusions: Our results suggest that IGF-I is an independent predictor of SBP in apparently healthy children. This association is potentiated in children with high Ca*P levels.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology