title: Obesity-asthma association: is it explained by systemic oxidant stress?
abstract: BACKGROUND
  The mechanism for the obesity-asthma association is unknown. This study evaluated the hypothesis that systemic oxidant stress explains this association.
  
  
  METHODS
  This cross-sectional study used year-20 follow-up evaluation data of 2,865 eligible participants in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. Current asthma was self-reported. Oxidant stress primarily was assessed by plasma F2-isoprostane concentrations. Obesity measures included categories of BMI and dual-energy x-ray absorptiometry-assessed fat mass index (FMI) and lean mass index (LMI). Logistic and linear regressions were used for analyses.
  
  
  RESULTS
  Asthma was associated with higher plasma F2-isoprostane concentrations (p = 0.049); however, this association was not significant when adjusted for either gender or BMI. The BMI-asthma association was seen only among women (p = 0.03; gender-specific interaction, p = 0.01), and this association was not explained by plasma F2-isoprostane levels. Similarly, both FMI and LMI were positively associated with asthma in women (p = 0.20 and 0.01, respectively). These associations also were not explained by plasma F2-isoprostane levels. Similar results were obtained when plasma levels of oxidized low-density lipoprotein were used instead of F2-isoprostane levels to study the BMI-asthma association at the year-15 evaluation.
  
  
  CONCLUSIONS
  Systemic oxidant stress, primarily assessed by plasma F2-isoprostane concentrations, was not independently associated with asthma and, therefore, may not explain the obesity-asthma association in women. The asthma-oxidant stress association is confounded by gender and obesity. This study is limited by the inability to measure airway oxidant stress. It is possible that another (as yet undetermined) measure of systemic oxidant stress may be more relevant in asthma.
authors: Department of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM. Electronic address: asood@salud.unm.edu.
authors: Akshay
authors: A
authors: Sood
authors: Clinical Translational Sciences Center, University of New Mexico Health Sciences Center, Albuquerque, NM.
authors: Clifford
authors: C
authors: Qualls
authors: Department of Preventive Medicine, University of Alabama at Birmingham, Birmingham, AL.
authors: Alexander
authors: A
authors: Arynchyn
authors: Department of Medicine, Mount Auburn Hospital, Cambridge, MA.
authors: William S
authors: WS
authors: Beckett
authors: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN.
authors: Myron D
authors: MD
authors: Gross
authors: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN.
authors: Michael W
authors: MW
authors: Steffes
authors: Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL.
authors: Lewis J
authors: LJ
authors: Smith
authors: Department of Experimental Surgery and Anesthesiology, Katholieke Universiteit Leuven, Leuven, Belgium.
authors: Paul
authors: P
authors: Holvoet
authors: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN.
authors: Bharat
authors: B
authors: Thyagarajan
authors: Division of Epidemiology, University of Minnesota, Minneapolis, MN; Institute for Nutrition Research, University of Oslo, Oslo, Norway.
authors: David R
authors: DR
authors: Jacobs
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000150:complications* / Q000503:physiopathology; D015992:Body Mass Index; D008078:Cholesterol, LDL / Q000097:blood; D003430:Cross-Sectional Studies; D028441:F2-Isoprostanes / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000503:physiopathology; D018384:Oxidative Stress / Q000502:physiology*; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D008078:Cholesterol, LDL; D028441:F2-Isoprostanes