Fat Attenuation at CT in Anorexia Nervosa.
OBJECTIVE
To investigate the composition, cross-sectional area (CSA), and hormonal correlates of different fat depots in women with anorexia nervosa (AN) and control subjects with normal weights to find out whether patients with AN have lower fat CSA but higher attenuation than did control subjects and whether these changes may be mediated by gonadal steroids, cortisol, and thyroid hormones.


METHODS
This study was institutional review board approved and HIPAA compliant. Written informed consent was obtained. Forty premenopausal women with AN and 40 normal-weight women of comparable age (mean age ± standard deviation, 26 years ± 5) were studied. All individuals underwent computed tomography of the abdomen and thigh with a calibration phantom. Abdominal subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), thigh SAT, and thigh intermuscular adipose tissue CSA and attenuation were quantified. Serum estradiol, thyroid hormones, and urinary free cortisol levels were assessed. Variables were compared by using analysis of variance. Associations were examined by using linear regression analysis.


RESULTS
Women with AN had higher fat attenuation than did control subjects (-100.1 to -46.7 HU vs -117.6 to -61.8 HU, P < .0001), despite lower fat CSA (2.0-62.8 cm(2) vs 5.5-185.9 cm(2), P < .0001). VAT attenuation but not CSA was inversely associated with lowest prior lifetime body mass index in AN (r = -0.71, P = .006). Serum estradiol levels were inversely associated with fat attenuation (r = -0.34 to -0.61, P = .03 to <.0001) and were positively associated with fat CSA of all compartments (r = 0.42-0.64, P = .007 to <.0001). Thyroxine levels and urinary free cortisol levels were positively associated with thigh SAT attenuation (r = 0.64 [P = .006] and r = 0.68 [P = .0004], respectively) and were inversely associated with abdominal SAT and VAT CSA (r = -0.44 to -0.58, P = .04 to .02).


CONCLUSIONS
Women with AN have differences in fat composition, with higher fat attenuation than that of control subjects, as well as low fat mass. VAT attenuation but not CSA is inversely associated with lowest prior lifetime body mass index, suggesting that fat attenuation may serve as a biomarker of prior and current disease status in AN.
From the Department of Radiology (C.M.G., M.T., M.A.B.) and Neuroendocrine Unit (K.K.M., A.K.), Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Md (R.M., T.B.H.).
Corey M
CM
Gill
From the Department of Radiology (C.M.G., M.T., M.A.B.) and Neuroendocrine Unit (K.K.M., A.K.), Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Md (R.M., T.B.H.).
Martin
M
Torriani
From the Department of Radiology (C.M.G., M.T., M.A.B.) and Neuroendocrine Unit (K.K.M., A.K.), Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Md (R.M., T.B.H.).
Rachel
R
Murphy
From the Department of Radiology (C.M.G., M.T., M.A.B.) and Neuroendocrine Unit (K.K.M., A.K.), Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Md (R.M., T.B.H.).
Tamara B
TB
Harris
From the Department of Radiology (C.M.G., M.T., M.A.B.) and Neuroendocrine Unit (K.K.M., A.K.), Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Md (R.M., T.B.H.).
Karen K
KK
Miller
From the Department of Radiology (C.M.G., M.T., M.A.B.) and Neuroendocrine Unit (K.K.M., A.K.), Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Md (R.M., T.B.H.).
Anne
A
Klibanski
From the Department of Radiology (C.M.G., M.T., M.A.B.) and Neuroendocrine Unit (K.K.M., A.K.), Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Yawkey 6E, Boston, MA 02114; and Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Md (R.M., T.B.H.).
Miriam A
MA
Bredella
D000273:Adipose Tissue / Q000000981:diagnostic imaging*; D000328:Adult; D000856:Anorexia Nervosa / Q000000981:diagnostic imaging*; D015415:Biomarkers / Q000097:blood; D001823:Body Composition; D005260:Female; D006728:Hormones / Q000097:blood; D006801:Humans; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
D015415:Biomarkers; D006728:Hormones