ESPE Abstracts

Objective: Peak stimulated growth hormone (GH) levels are lower in overweight and obese subjects and it has been suggested that results of tests should be adjusted for body mass index (BMI). The study aimed - A. To evaluate the association between growth hormone peak levels and body mass index (BMI) in a single center. B. To discuss the biological and clinical significance of the findings and make recommendations based on a literature review.

Design & Methods: A. This was a retrospective study of results from a single testing center. Peak GH levels and BMI standard deviation scores (BMI-SDS) for a total of 988 tests (Clonidine – 694, Glucagon – 198, Arginine – 96) were analyzed. B. Relevant other studies were reviewed.

Results: Mean peak GH levels were significantly lower in arginine (P = 0.015) and clonidine tests (P = 0.018) starting at BMI standard deviation score over 1 compared to below 1 BMI-SDS. The differences still remained significant for a subgroup with peaks below 7.5 ng/dl (P = 0.003 and P = 0.042 respectively). Overweight and obese subjects tend to be tall and are infrequently encountered in studies of GH testing. In the literature, obese patients responded better than lean patients to GH treatment with greater increases in height and IGF-1. Obese subjects with low GH peaks had high carotid intima-media thickness (cIMT) that improved with GH therapy. These findings suggest physiologically important genuine GH deficiency in short overweight individuals.

Conclusion: Overweight short children testing GH deficient should be treated with growth hormone without "corrections" for BMI.