title: Opposite associations of age-dependent insulin-like growth factor-I standard deviation scores with nutritional state in normal weight and obese subjects.
abstract: OBJECTIVE
  Insulin-like growth factor-I (IGF-I) has been suggested to be a prognostic marker for the development of cancer and, more recently, cardiovascular disease. These diseases are closely linked to obesity, but reports of the association of IGF-I with measures of obesity are divergent. In this study, we assessed the association of age-dependent IGF-I standard deviation scores with body mass index (BMI) and intra-abdominal fat accumulation in a large population.
  
  
  METHODS
  A cross-sectional, epidemiological study.
  
  
  METHODS
  IGF-I levels were measured with an automated chemiluminescence assay system in 6282 patients from the DETECT study. Weight, height, and waist and hip circumference were measured according to the written instructions. Standard deviation scores (SDS), correcting IGF-I levels for age, were calculated and were used for further analyses.
  
  
  RESULTS
  An inverse U-shaped association of IGF-I SDS with BMI, waist circumference, and the ratio of waist circumference to height was found. BMI was positively associated with IGF-I SDS in normal weight subjects, and negatively associated in obese subjects. The highest mean IGF-I SDS were seen at a BMI of 22.5-25 kg/m2 in men (+0.08), and at a BMI of 27.5-30 kg/m2 in women (+0.21). Multiple linear regression models, controlling for different diseases, medications and risk conditions, revealed a significant negative association of BMI with IGF-I SDS. BMI contributed most to the additional explained variance to the other health conditions.
  
  
  CONCLUSIONS
  IGF-I standard deviation scores are decreased in obesity and underweight subjects. These interactions should be taken into account when analyzing the association of IGF-I with diseases and risk conditions.
authors.affiliation: Institute of Clinical Psychology and Psychotherapy, Technical University of Dresden, Germany. schneider@mpipsykl.mpg.de
authors.forename: Harald Jörn
authors.initials: HJ
authors.lastname: Schneider
authors.forename: Bernhard
authors.initials: B
authors.lastname: Saller
authors.forename: Jens
authors.initials: J
authors.lastname: Klotsche
authors.forename: Winfried
authors.initials: W
authors.lastname: März
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Erwa
authors.forename: Hans-Ullrich
authors.initials: HU
authors.lastname: Wittchen
authors.forename: Günter Karl
authors.initials: GK
authors.lastname: Stalla
mesh_terms: D050153:Abdominal Fat; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D015415:Biomarkers; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D009765:Obesity / Q000453:epidemiology / Q000378:metabolism*; D011379:Prognosis; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D007334:Insulin-Like Growth Factor I