Endocrine Abstracts

Background: Adults with GH deficiency (GHD) have altered body composition with an increase in abdominal fat when compared with healthy matched controls. However, most studies have not compared GHD adults with GHD adults on GH replacement.

Abdominal fat is composed of subcutaneous abdominal tissue (SAT) and visceral abdominal tissue (VAT). Increased VAT is associated with poor metabolic outcomes. Magnetic Resonance Imaging (MRI) is a reliable and reproducible means of quantifying abdominal fat distribution. Our aim was to assess and compare VAT and SAT compartments in untreated GHD adults, treated GHD adults and matched healthy controls.

Methods: Eighteen untreated GHD adults, 17 treated GHD adults and 19 age and sex matched healthy volunteers were recruited. Fifteen patients had combined pituitary hormone deficiency in both the untreated and treated GHD groups. The remaining had isolated GHD. All patients underwent anthropometric assessment, bio impedance analysis and MR Imaging of their abdomen at the level of L4/L5. Minitab v16 was used for statistical analysis.

Results: Matched healthy controls had lower body fat % (P=0.046), total abdominal fat (P=0.021), SAT (P=0.031) and VAT (P=0.028) when compared to GH deficient patients off and on GH replacement. GH replacement was not associated with changes in body fat %, total abdominal fat, VAT or SAT. There was no difference in fat distribution (VAT/SAT ratio) between the three groups (P=0.47).

Conclusions: There were no major alterations in body fat distribution in untreated GHD adults when compared with treated GHD adults. However, both treated and untreated GHD adults have increased body fat % and abdominal fat when compared to healthy controls. This is likely to reflect the causes and consequences of hypopituitarism rather than the effects of GH deficiency in isolation. We conclude that both treated and untreated GHD patients have increased fat mass but the distribution of this fat is no different to control subjects.

Declaration of funding: This work was supported by funds from Pfizer inc and Merc Serono, Inc.