Does Obesity Cause Stress which Causes Asthma

BrooklynDodger(s): Maybe the causality is that psychosocial stress causes both obesity and asthma?

Chest 2009;136 1055-1062

http://chestjournal.chestpubs.org/cgi/content/abstract/136/4/1055?etoc

Obesity-Asthma Association

Is It Explained by Systemic Oxidant Stress?

1. Akshay Sood, MD, MPH, FCCP,
2. Clifford Qualls, PhD,
3. Alexander Arynchyn, MD, PhD,
4. William S. Beckett, MD, MPH, FCCP,
5. Myron D. Gross, PhD,
6. Michael W. Steffes, MD, PhD,
7. Lewis J. Smith, MD,
8. Paul Holvoet, PhD,
9. Bharat Thyagarajan, MD, PhD and
10. David R. Jacobs, Jr, PhD

+ Author Affiliations

1. From the Department of Medicine (Dr. Sood) and Clinical Translational Sciences Center (Dr. Qualls), University of New Mexico Health Sciences Center, Albuquerque, NM; Department of Preventive Medicine (Dr. Arynchyn), University of Alabama at Birmingham, Birmingham, AL; Department of Medicine (Dr. Beckett), Mount Auburn Hospital, Cambridge, MA; Department of Laboratory Medicine and Pathology (Drs. Gross, Steffes, and Thyagarajan) and Division of Epidemiology (Dr. Jacobs), University of Minnesota, Minneapolis, MN; Department of Medicine (Dr. Smith), Feinberg School of Medicine, Northwestern University, Chicago, IL; Department of Experimental Surgery and Anesthesiology (Dr. Holvoet), Katholieke Universiteit Leuven, Leuven, Belgium; and Institute for Nutrition Research (Dr. Jacobs), University of Oslo, Oslo, Norway.

1. Akshay Sood, MD, MPH, FCCP, Associate Professor of Medicine, University of New Mexico Health Sciences Center School of Medicine, Department of Medicine, 1 University of New Mexico, MSC 10 5550, Albuquerque, NM 87131; e-mail: asood@salud.unm.edu

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.