title: IGF-1 levels across the spectrum of normal to elevated in acromegaly: relationship to insulin sensitivity, markers of cardiovascular risk and body composition.
abstract: OBJECTIVE
  Activity of acromegaly is gauged by levels of GH and IGF-1 and epidemiological studies demonstrate that their normalization reduces acromegaly's excess mortality rate. However, few data are available linking IGF-1 levels to features of the disease that may relate to cardiovascular (CV) risk. Therefore, we tested the hypothesis that serum IGF-1 levels relative to the upper normal limit relate to insulin sensitivity, serum CV risk markers and body composition in acromegaly.
  
  
  METHODS
  In this prospective, cross-sectional study conducted at a pituitary tumor referral center we studied 138 adult acromegaly patients, newly diagnosed and previously treated surgically, with fasting and post-oral glucose levels of endocrine and CV risk markers and body composition assessed by DXA.
  
  
  RESULTS
  Active acromegaly is associated with lower insulin sensitivity, body fat and CRP levels than acromegaly in remission. %ULN IGF-1 strongly predicts insulin sensitivity, better than GH and this persists after adjustment for body fat and lean tissue mass. %ULN IGF-1 also relates inversely to CRP levels and fat mass, positively to lean tissue and skeletal muscle estimated (SM(E)) by DXA, but not to blood pressure, lipids, BMI or waist circumference. Gender interacts with the IGF-1-lean tissue mass relationship.
  
  
  CONCLUSIONS
  Active acromegaly presents a unique combination of features associated with CV risk, reduced insulin sensitivity yet lower body fat and lower levels of some serum CV risk markers, a pattern that is reversed in remission. %ULN IGF-1 levels strongly predict these features. Given the known increased CV risk of active acromegaly, these findings suggest that of these factors insulin resistance is most strongly related to disease activity and potentially to the increased CV risk of active acromegaly.
authors.affiliation: Department of Medicine, Columbia University, College of Physicians and Surgeons, 650 West 168th Street, 9-905, New York, NY, 10032, USA.
authors.forename: Tirissa J
authors.initials: TJ
authors.lastname: Reid
authors.affiliation: Department of Biostatistics, Columbia University, College of Physicians and Surgeons, New York, NY, 10032, USA.
authors.forename: Zhezhen
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Department of Medicine, Columbia University, College of Physicians and Surgeons, 650 West 168th Street, 9-905, New York, NY, 10032, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.affiliation: Department of Medicine, Columbia University, College of Physicians and Surgeons, 650 West 168th Street, 9-905, New York, NY, 10032, USA.
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Reyes-Vidal
authors.affiliation: Department of Medicine, Columbia University, College of Physicians and Surgeons, 650 West 168th Street, 9-905, New York, NY, 10032, USA.
authors.forename: Jean Carlos
authors.initials: JC
authors.lastname: Fernandez
authors.affiliation: Department of Neurosurgery, Columbia University, College of Physicians and Surgeons, New York, NY, 10032, USA.
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Bruce
authors.affiliation: Department of Neurosurgery, Mt. Sinai School of Medicine, New York, NY, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Kostadinov
authors.affiliation: Department of Neurosurgery, Mt. Sinai School of Medicine, New York, NY, USA.|Department of Medicine, Mt. Sinai School of Medicine, New York, NY, USA.
authors.forename: Kalmon D
authors.initials: KD
authors.lastname: Post
authors.affiliation: Department of Medicine, Columbia University, College of Physicians and Surgeons, 650 West 168th Street, 9-905, New York, NY, 10032, USA. puf1@columbia.edu.
authors.forename: Pamela U
authors.initials: PU
authors.lastname: Freda
mesh_terms: D000172:Acromegaly / Q000097:blood / Q000378:metabolism*; D000328:Adult; D001823:Body Composition / Q000502:physiology; D002318:Cardiovascular Diseases / Q000097:blood / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D007334:Insulin-Like Growth Factor I
keywords: Acromegaly; Body composition; IGF-1; Insulin sensitivity