Endocrine Abstracts

Introduction: Apart from being individually associated with cardiometabolic health, Vitamin D and growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis are reported to interplay, with a positive correlation between IGF-1 and 25-hydroxyvitamin D (25(OH)D). These findings raise questions about the role of vitamin D for the adverse cardiovascular (CV) risk profile in hyposomatotropism. Thus, the aim of our study was to investigate the association between 25(OH)D and metabolic syndrome (MetS), its components and other surrogate markers of CV risk.

Methods: This cross-sectional study included 129 adults with GHD, 41.9% with childhood-onset GHD. Each subject underwent routine biochemical blood testing, anthropometric (body mass index (BMI), waist circumference (WC), waist-to-hip ratio, percent body fat (PBF), visceral fat area (VFA), skeletal muscle mass) and blood pressure (BP) measurements. Other CV risk markers were examined in a subsample of the initial population - high-sensitivity C-reactive protein, adiponectin and asymmetric dimethylarginine (n=88); intima-media thickness of carotid arteries (n=44). Total serum 25(OH)D was used to assess vitamin D status and was measured by electro-chemiluminescence binding assay. Vitamin D status and GHD were defined according to the Endocrine Society Clinical Practice Guideline recommendations.

Results: Our data demonstrated significantly lower 25(OH)D levels among patients with MetS (11.8±4.5 vs. 16.3±8.1 ng/ml in those without MetS, P<0.0001). Serum 25(OH)D correlated negatively and weakly with anthropometric parameters (BMI, WC, PBF, VFA) and systolic BP.

Conclusion: The severe impairment of vitamin D status in hyposomatotropism and its association with adiposity and BP warrant 25(OH)D testing in GHD patients. Although the normalization of the vitamin D status has not been proven to improve CV outcomes in general population, it might have beneficial effects in GHD subjects, especially in those with obesity or hypertension. Patients with a combination of GHD, hypovitaminosis D and MetS show an adverse CV risk profile and need more active therapeutic care.