Original Articles: Asthma, Lower Airway Diseases
Obesity, inflammation, and asthma severity in childhood: data from the National Health and Nutrition Examination Survey 2001-2004

https://doi.org/10.1016/S1081-1206(10)60356-0Get rights and content

Background

The prevalences of asthma and obesity in children have increased significantly during the past 2 decades. The basis for the relationship between pediatric asthma and obesity is not well established.

Objectives

To explore the association between obesity and asthma severity in children and adolescents and to test whether obesity-induced inflammation, as characterized by serum C-reactive protein (CRP), is associated with increased severity of asthma.

Methods

Retrospective cohort analysis of interview, physical examination, and laboratory test data from participants younger than 20 years in 2 rounds of the National Health and Nutrition Examination Survey (2001-2002 and 2003-2004). We also performed generalized ordered logistic regression to evaluate the effect of body mass index (BMI) z score and CRP level on asthma severity, controlling for the impact of age, sex, race, income, insurance, and tobacco smoke exposure.

Results

Of the 77 million individuals younger than 20 years represented by this weighted sample, 19% met the study-defined criteria for asthma; most cases were defined as mild (11%) or moderate (6%); 2% had severe asthma. In multivariable models, elevated BMI z scores (odds ratio, 1.12; 95% confidence interval, 1.05-1.21) were associated with worse asthma severity. Elevated CRP level was associated with obesity (P < .001) and asthma severity (odds ratio, 1.33; 95% confidence interval, 1.16-1.52).

Conclusions

Higher BMI z scores and elevated serum CRP levels are associated with increased asthma severity. These findings highlight the importance of controlling for inflammation when considering the role of obesity and provide support for the hypothesis that obesity-induced inflammation may contribute to greater asthma severity.

Section snippets

INTRODUCTION

Asthma and obesity are concurrently at historic high levels in pediatric populations. 1 These 2 public health epidemics share risk factors (eg, poverty and physical inactivity); asthmatic children also may be at higher risk for obesity due to reduced exercise capacity. 2, 3 Mounting evidence suggests, however, that obesity independently contributes to the incidence and severity of asthma in children and adults. 4, 5 Although controversy persists regarding the exact nature of the relationship,

Sample

The National Health and Nutrition Examination Survey (NHANES) is a federally funded data collection effort that combines interviews and physical examinations to survey the health and nutritional status of the US population. Selected individuals participate in a detailed home interview that includes demographic, socioeconomic, and health-related questions and undergo a comprehensive examination that includes medical, dental, and laboratory analysis at 1 of the mobile examination centers. We used

RESULTS

The full NHANES sample included 10,140 participants aged 0 to 19 years, representative of 76,805,481 US children. The mean (SD) age of the sample was 9.3 (6.3) years, 49.7% were girls, 30% were white, 31% were black, 34% were Mexican American and other Hispanic, and 5% were “other” racial/ethnic groups, weighted by the NHANES to represent a population with a mean age of 9.5 years, 49.2% girls, 61% white, 14% black, 18% Mexican American and other Hispanic, and 6% other racial/ethnic groups (

DISCUSSION

Asthma severity is associated with an elevated BMI and a higher serum CRP level in a representative national cohort of 0- to 19-year-olds studied between 2001 and 2004. Furthermore, when participants with the most severe symptoms of asthma are compared with the rest of the cohort, the association with elevated CRP levels is at its most pronounced.

Leptin, adiponectin, chemokines, and cytokines have been suggested as causes of the inflammation seen in the obese state. 23 In fact, low-level

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    Disclosures: Authors have nothing to disclose.

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    Copyright © 2009 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.