Lipid patterns in treated growth hormone deficient children vs. short stature controls.

CONTEXT: Previous studies in adults with growth hormone (GH) deficiency have substantiated an increased risk of cardiovascular events. This risk has been attributed to an unpropitious lipid profile, increased abdominal mass, and higher incidence of metabolic syndrome. In these studies, a collateral observation has been a negative correlation between IGF-1 levels and lipid profiles. Longitudinal studies are lacking in children with GH-deficiency wherein the various lipid subfractions after GH treatment were compared to matched GH-sufficient short stature controls. Our study examined changes in small lipid particles following GH treatment. OBJECTIVE: The primary objective was to determine the effect of GH treatment on serum lipids in GH-deficient patients vs. short controls. DESIGN, SETTING, AND PARTICIPANTS: This was a prospective, unblinded, case-controlled, 6-month trial conducted at a tertiary pediatric referral center. Patients were referred for short stature. Incorporating accepted criteria, the treatment group (n=18) was found to be GH-deficient, whereas the control group (n=13) was GH-sufficient. The two groups had near-identical short stature along in addition to baseline measurements of weight and BMI. INTERVENTIONS: The treatment arm received 6 months of recombinant GH at standard doses. MAIN OUTCOME MEASURES: The primary endpoint was the comparison of the lipoprotein subclasses and lipids between the two groups after 6 months. RESULTS: With the exception of the intermediate density lipoprotein (IDL), there were no significant differences at baseline in serum lipid profiles between the GH-deficient children and the controls. After 6 months of therapy, there were statistically significant differences in Apo-B, LDL, and smaller lipoparticles (LDL-3 and non-HDL) in GH-treated children compared to untreated GH-sufficient short children. CONCLUSIONS: Our findings indicate that GH replacement may improve cardiovascular outcome by favorably altering lipid profiles.

Serum 25-hydroxyvitamin D and Ethnic Differences in Arterial Stiffness and Endothelial Function.

BACKGROUND: Vitamin D reportedly influences vascular function, which is worse in African Americans (AAs) relative to European Americans (EAs). It is not clear if ethnic differences in 25(OH)D mediate differences in vascular function. This study examined the relationships of serum 25-hydroxyvitamin D (25(OH)D) with indicators of vascular function among healthy, young AA and EA adults. METHODS: This is a cross sectional study involving 23 AAs and 22 EAs. The main outcomes were augmentation index (AIx75), central aortic pressure, pulse wave velocity (PWV), flow-mediated dilation (FMD), and seated and supine blood pressures. RESULTS: Results indicated that 25(OH)D was inversely associated with AIx75, supine systolic blood pressure (SBP), central aortic SBP and central aortic diastolic blood pressure (DBP), independent of age, sex, and percent body fat (standardized ß= -0.29 to -0.43, P < 0.05 for all). AAs had greater AIx75 (P = 0.04) and PWV (P = 0.07) and lower FMD (P = 0.02) compared to EA after adjusting for age and percent body fat; further adjustment for 25(OH)D reduced the ethnic differences (P = 0.44, 0.53, and 0.20, respectively). CONCLUSION: The 25(OH)D was associated with vascular function in healthy adults, and lower 25(OH)D among AAs may contribute to their greater arterial stiffness and reduced endothelial function (Clinical trials.gov NCT01041365, NCT01041547).