Abstract Archives of the RSNA, 2011


SSG09-01

Growth Hormone Administration Increases Bone Formation and Bone Marrow Fat in Premenopausal Women with Abdominal Obesity

Scientific Formal (Paper) Presentations

Presented on November 29, 2011
Presented as part of SSG09: Musculoskeletal (Metabolic Conditions, Osteoporosis, and Infection)

Participants

Miriam Antoinette Bredella MD, Presenter: Nothing to Disclose
Eleanor Lin, Abstract Co-Author: Nothing to Disclose
Danielle J Brick, Abstract Co-Author: Nothing to Disclose
Anu V Gerweck, Abstract Co-Author: Nothing to Disclose
Lindsey M Harrington, Abstract Co-Author: Nothing to Disclose
Martin Torriani MD, Abstract Co-Author: Nothing to Disclose
Bijoy J. Thomas MD, Abstract Co-Author: Nothing to Disclose
Anne Klibanski MD, Abstract Co-Author: Nothing to Disclose
Karen K. Miller MD, Abstract Co-Author: Nothing to Disclose

PURPOSE

Recent studies suggest that abdominal adiposity is associated with low bone mineral density (BMD), high bone marrow (BM) fat, and low growth hormone (GH). Bone and fat cells arise from the same mesenchymal stem cells within BM, and GH is an important regulator of bone homeostasis. BMD is low in GH-deficient patients with pituitary disorders, and GH increases bone formation, with a decrease in BMD at 6 months, as bone expands, before mineralization, followed by an increase in BMD by 18 months. We hypothesized that 6 months of GH would increase bone formation and BM fat and decrease BMD in women with abdominal obesity.

METHOD AND MATERIALS

79 premenopausal women with abdominal adiposity (mean age:36±7 y, mean BMI:35±5 kg/m2) participated in a 6-month, randomized, double-blind, placebo-controlled trial of GH administration. BM fat was determined by 1-H MRS and BMD by DXA. Abdominal fat depots and thigh muscle area were assessed by CT. P1NP, a marker of bone formation, CTX, a marker of bone resorption, and 25-OH vitamin D were assessed. Mean baseline and 6-month change were compared with ANOVA. Linear regression analysis was performed to determine predictors of bone turnover.

RESULTS

At baseline 32% of subjects were osteopenic (t-score <-1 and >-2.5) and 1 subject had osteoporosis (t-score <-2.5). GH increased IGF-1, P1NP, CTX, vitamin D, muscle mass, and BM fat, and decreased abdominal fat and BMD compared with placebo (p<0.05). 6-month change in P1NP correlated with 6-month change in CTX (r=0.34, p=0.04), consistent with the known coupling of bone formation and resorption. 6-month change in abdominal fat inversely predicted 6-month change in P1NP (r= -0.40, p=0.05), suggesting that subjects with the greatest loss of abdominal fat had greater increases in bone formation.

CONCLUSION

Low BMD is common in abdominally obese women. GH-induced loss of abdominal fat is associated with increased bone formation, consistent with a detrimental effect of abdominal fat on bone. GH replacement in abdominally obese women for 6 months increases bone formation and BM fat. The increase in BM fat content may reflect changes in energy demand from increased bone turnover.

CLINICAL RELEVANCE/APPLICATION

Obesity does not always protect against osteoporosis. Loss of abdominal fat improves bone health. Replacement of GH for 6 months increases bone formation and bone marrow fat in abdominally obese women

Cite This Abstract

Bredella, M, Lin, E, Brick, D, Gerweck, A, Harrington, L, Torriani, M, Thomas, B, Klibanski, A, Miller, K, Growth Hormone Administration Increases Bone Formation and Bone Marrow Fat in Premenopausal Women with Abdominal Obesity.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11008219.html