Association of childhood obesity with atopic and nonatopic asthma: results from the National Health and Nutrition Examination Survey 1999-2006.
BACKGROUND
Obesity and asthma prevalence have both risen among children over the last several decades, and research efforts increasingly suggest that obesity is associated with asthma. Some, but not all, studies have shown that the effect of obesity on asthma is stronger among nonatopic individuals than among those with atopy. Systemic inflammation may be a factor in this relationship.


OBJECTIVE
To examine the association of obesity with atopic and nonatopic asthma among U.S. children and to assess the role of C-reactive protein.


METHODS
Nationally representative data from the National Health and Nutrition Examination Survey (NHANES) were used to examine the relationship of weight to current asthma using logistic regression. Overweight was defined as ≥ 85th percentile of body mass index (BMI)-for-age and obesity was defined as ≥ 95th percentile of BMI-for-age. The presence of at least one positive allergen-specific immunoglobulin E (IgE) was used to stratify the relationship by atopic status in 2005-2006 data (n = 3387). Setting and Participants. Stratified, multistage probability sampling was used to identify survey participants. This analysis includes children ages 2-19 (n = 16,074) from the 1999-2006 NHANES who have information on BMI and current asthma.


METHODS
Self-report of doctor-diagnosed current asthma.


RESULTS
Obesity was significantly related to current asthma among children and adolescents (odds ratio [OR]: 1.68, 95% confidence interval [CI]: 1.33, 2.12). The association was stronger in nonatopic children (OR: 2.46, 95% CI: 1.21, 5.02) than in atopic children (OR: 1.34, 95% CI: 0.70, 2.57) (interaction p value = .09). C-reactive protein levels were associated with current asthma in nonatopic children, but not after adjusting for BMI.


CONCLUSIONS
Excess weight in children is associated with higher rates of asthma, especially asthma that is not accompanied by allergic disease.
Visness
Cynthia M
CM
Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27517, U.S.A. cindy_visness@rhoworld.com
London
Stephanie J
SJ
Daniels
Julie L
JL
Kaufman
Jay S
JS
Yeatts
Karin B
KB
Siega-Riz
Anna-Maria
AM
Calatroni
Agustin
A
Zeldin
Darryl C
DC
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000453:epidemiology*; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003625:Data Collection; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D009765:Obesity / Q000150:complications*; D013997:Time Factors; D055815:Young Adult
D007073:Immunoglobulin E; D002097:C-Reactive Protein