The Impact of Weight on Insulin-like Growth Factor-1 Levels in Short-Statured Children Treated With Growth Hormone.

OBJECTIVE

To examine how weight status influences insulin-like growth factor-1 (IGF-1) levels and growth outcomes in short statured children treated with growth hormone (GH) for GH deficiency or idiopathic short stature.

METHODS

This retrospective cohort study analyzed 293 children (95 GH deficiency, 197 idiopathic short stature) treated with GH in an endocrine clinic at a tertiary pediatric referral center (2016-2021). Data were collected at baseline and years 1-3, including auxological parameters, pubertal staging, GH dose, and IGF-1 levels. Mixed-model analyses examined the effects of weight on height standard deviation score (Ht-SDS), IGF-1-SDS, and GH dosing over a 3-year period.

RESULTS

Body mass index-SDS positively correlated with IGF-1-SDS (B = 0.150, P < .001). Overweight/obese children consistently demonstrated higher IGF-1 SD scores than normal-weight children (P < .001), despite receiving lower GH doses (P = .034). Both weight groups showed comparable height-SDS improvements over time (P < .001), with no significant difference in growth response (P = .685). Body surface area was positively associated with IGF-1-SDS at all-time points. Pubertal status significantly influenced IGF-1 levels.

CONCLUSIONS

Weight status has a significant influence on IGF-1 levels in children treated with GH, with overweight/obese children exhibiting elevated IGF-1 levels despite receiving lower GH doses. These elevations likely represent a normal physiological response rather than overtreatment. Our findings underscore the importance of considering weight when monitoring IGF-1 levels and adjusting GH doses in clinical practice.