The Influence of Body Mass Index on the Growth Hormone Peak Response Regarding Growth Hormone Stimulation Tests in Children

Introduction: Several studies have analyzed the association between the maximal growth hormone serum level obtained during a growth hormone stimulation test (GHMax) and the body mass index-standard deviation score (BMI-SDS). However, as sample sizes were quite small, our study aimed to analyze the association between GHMax and BMI-SDS within a large cohort of 991 children. Further, we investigated other influencing factors, like test type, age, sex, puberty, and preterm birth. Methods: Children with short stature (height <10th percentile) received growth hormone stimulation tests with arginine or glucagon at the Department of Paediatric Endocrinology of the University of Leipzig Medical Center. The study population included a total of 1,438 tests (633 tests on girls, 805 tests on boys), with the majority consisting of prepubertal children (tests = 1,138). The mean age at testing was 7.74 years. Analyses were carried out on the entire cohort as well as stratified by test types. We performed univariate and multivariate analyses using linear mixed-effect models to assess the effects on GHMax. Results: GHMax and BMI-SDS were significantly negatively associated with an effect size of β = −1.10 (p < 0.001), independent from the test type. The GHMax values were significantly (p < 0.001) higher for glucagon (mean value: 9.65 ng/mL) than those for arginine tests (mean value: 8.50 ng/mL). Age, sex, premature birth, and puberty were not significantly related to GHMax values. Conclusion: We confirmed the negative association between GHMax and weight status of short children found in previous studies. Therefore, considering BMI-SDS may be helpful in the assessment of growth hormone stimulation tests in short-statured children, but it should not be the determining factor for a treatment decision.