OR10-4 IGF-1 is Associated with Bone Strength in Anorexia Nervosa

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: OR10-Osteoporosis
Clinical
Saturday, June 15, 2013: 11:30 AM-1:00 PM
Presentation Start Time: 12:15 PM
Room 121 (Moscone Center)
Pouneh K Fazeli*1, Alexander Terence Faje1, Stephen T Russell2, Clifford J Rosen3, Mary Larsen Bouxsein4 and Anne Klibanski5
1Neuroendocrine Unit, Massachusetts General Hospital/Harvard Medical School, Boston, MA, 2Massachusetts General Hospital/Neuroendocrine Unit, Boston, MA, 3Maine Medical Center Research Institute, Scarborough, ME, 4Beth Israel Deaconess Med, Boston, MA, 5Massachusetts General Hospital/Harvard Medical School, Boston, MA
Anorexia nervosa (AN) is a psychiatric disorder characterized by extreme, self-induced starvation affecting 0.5-1% of college-aged women in the US. The disorder is associated with multiple medical comorbidities, including significant bone loss and a seven-fold increased risk of fracture compared to controls. Microarchitectural methods of evaluating bone structure allow for the evaluation of both cortical and trabecular parameters and finite element analysis (FEA) enables assessment of bone strength, a predictor of fracture risk independent of BMD. Women with AN have decreased trabecular parameters, decreased cortical thickness and decreased bone strength compared to healthy controls as assessed by FEA. Hormonal predictors of measures of bone strength in women with AN have not been previously investigated. We hypothesized that two major nutritionally dependent hormones affecting bone, IGF-1 and leptin, would be predictors of decreased bone strength in this population. We studied 40 women [20 with AN, mean age +/- SD: 28.1 +/- 5.1 yrs and 20 healthy controls (HC): 27.5 +/- 3.2 yrs; p=0.66]. We measured stiffness and failure load of the distal radius and distal tibia by FEA of high resolution peripheral quantitative CT images and serum IGF-1 and leptin levels. By design, AN had a significantly lower % ideal body weight compared to HC (AN: 78.3 +/- 8.1% vs HC: 101.7 +/- 5.9%; p<0.0001). AN had significantly lower stiffness and failure load as compared to HC in both the radius (stiffness: AN: 67.1 +/- 17.3 KN/mm vs HC: 77.2 +/- 13.1 kN/mm, p=0.04; failure load: AN: 3.4 +/- 0.9 kN vs HC: 3.9 +/- 0.6 kN, p=0.03) and tibia (stiffness: AN: 183.3 +/- 44.8 kN/mm vs HC: 219.9 +/- 28.7 kN/mm, p<0.01; failure load: AN: 9.2 +/- 2.2 kN vs HC: 11.0 +/- 1.4 kN; p<0.01). Mean serum leptin and IGF-1 levels were significantly lower in AN compared to HC (Leptin: AN: 2.4 +/- 2.7 ng/mL vs HC: 11.1 +/- 7.0 ng/mL, p<0.0001; IGF-1: AN: 176.8 +/- 66 ng/mL vs HC: 245.6 +/- 61.9, p=0.001). IGF-1 was significantly associated with tibial stiffness (R=0.58; p<0.01) and failure load (R=0.61; p<0.01) and radial stiffness (R=0.57; p<0.01) and failure load (R=0.57; p<0.01) in AN but not in HC. There were no significant associations between leptin and stiffness or failure load in either group. Our data support the hypothesis that IGF-1 is a predictor of bone strength in AN.  Further studies are needed to delineate other potential hormonal predictors of bone strength in AN.

Nothing to Disclose: PKF, ATF, STR, CJR, MLB, AK

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: National Institute of Diabetes, Digestive and Kidney Diseases/National Institutes of Health grants R24DK092759 and K23 DK094820 (Fazeli); 1 UL1 RR025758-04, Harvard Clinical and Translational Science Center, from the National Center for Research Resources; 8 UL1 TR000170-05, Harvard Clinical and Translational Science Center, from the National Center for Advancing Translational Science