title: Inflammation and iron deficiency in the hypoferremia of obesity.
abstract: BACKGROUND
  Obesity is associated with hypoferremia, but it is unclear if this condition is caused by insufficient iron stores or diminished iron availability related to inflammation-induced iron sequestration.
  
  
  OBJECTIVE
  To examine the relationships between obesity, serum iron, measures of iron intake, iron stores and inflammation. We hypothesized that both inflammation-induced sequestration of iron and true iron deficiency were involved in the hypoferremia of obesity.
  
  
  METHODS
  Cross-sectional analysis of factors anticipated to affect serum iron.
  
  
  METHODS
  Outpatient clinic visits.
  
  
  METHODS
  Convenience sample of 234 obese and 172 non-obese adults.
  
  
  METHODS
  Relationships between serum iron, adiposity, and serum transferrin receptor, C-reactive protein, ferritin, and iron intake analyzed by analysis of covariance and multiple linear regression.
  
  
  RESULTS
  Serum iron was lower (75.8+/-35.2 vs 86.5+/-34.2 g/dl, P=0.002), whereas transferrin receptor (22.6+/-7.1 vs 21.0+/-7.2 nmol/l, P=0.026), C-reactive protein (0.75+/-0.67 vs 0.34+/-0.67 mg/dl, P<0.0001) and ferritin (81.1+/-88.8 vs 57.6+/-88.7 microg/l, P=0.009) were higher in obese than non-obese subjects. Obese subjects had a higher prevalence of iron deficiency defined by serum iron (24.3%, confidence intervals (CI) 19.3-30.2 vs 15.7%, CI 11.0-21.9%, P=0.03) and transferrin receptor (26.9%, CI 21.6-33.0 vs 15.7%, CI 11.0-21.9%, P=0.0078) but not by ferritin (9.8%, CI 6.6-14.4 vs 9.3%, CI 5.7-14.7%, P=0.99). Transferrin receptor, ferritin and C-reactive protein contributed independently as predictors of serum iron.
  
  
  CONCLUSIONS
  The hypoferremia of obesity appears to be explained both by true iron deficiency and by inflammatory-mediated functional iron deficiency.
authors: Unit on Growth and Obesity, Developmental Endocrinology Branch, National Institute of Child Health and Human Development, Bethesda, MD, USA.
authors: L B
authors: LB
authors: Yanoff
authors: C M
authors: CM
authors: Menzie
authors: B
authors: B
authors: Denkinger
authors: N G
authors: NG
authors: Sebring
authors: T
authors: T
authors: McHugh
authors: A T
authors: AT
authors: Remaley
authors: J A
authors: JA
authors: Yanovski
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018798:Anemia, Iron-Deficiency / Q000145:classification / Q000209:etiology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D005293:Ferritins; D006801:Humans; D007249:Inflammation; D000090463:Iron Deficiencies; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000209:etiology*; D011990:Receptors, Transferrin / Q000378:metabolism*
chemical_list: D011990:Receptors, Transferrin; D005293:Ferritins