Asthma and atopy in overweight children.
BACKGROUND
Obesity may be associated with an increase in asthma and atopy in children. If so, the effect could be due to an effect of obesity on lung volume and thus airway hyperresponsiveness.


METHODS
Data from 5993 caucasian children aged 7-12 years from seven epidemiological studies performed in NSW were analysed. Subjects were included if data were available for height, weight, age, skin prick test results to a common panel of aeroallergens, and a measure of airway responsiveness. History of doctor diagnosed asthma, wheeze, cough, and medication use was obtained by questionnaire. Recent asthma was defined as a doctor diagnosis of asthma ever and wheeze in the last 12 months. Body mass index (BMI) percentiles, divided into quintiles per year age, were used as a measure of standardised weight. Dose response ratio (DRR) was used as a measure of airway responsiveness. Airway hyperresponsiveness was defined as a DRR of >/=8.1. Adjusted odds ratios were obtained by logistic regression.


RESULTS
After adjusting for atopy, sex, age, smoking and family history, BMI was a significant risk factor for wheeze ever (OR = 1.06, p = 0.007) and cough (OR = 1.08, p = 0.001), but not for recent asthma (OR = 1.02, p = 0.43) or airway hyperresponsiveness (OR = 0.97 p = 0.17). In girls a higher BMI was significantly associated with higher prevalence of atopy (chi(2) trend 7.9, p = 0.005), wheeze ever (chi(2) trend 10.4, p = 0.001), and cough (chi(2) trend 12.3, p<0.001). These were not significant in boys.


CONCLUSIONS
Higher BMI is a risk factor for atopy, wheeze ever, and cough in girls only. Higher BMI is not a risk factor for asthma or airway hyperresponsiveness in either boys or girls.
Schachter
L M
LM
Woolcock Institute, University of Sydney, Sydney, NSW 2006, Australia. lindams@bigpond.com
Peat
J K
JK
Salome
C M
CM
D000704:Analysis of Variance; D001249:Asthma / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D015992:Body Mass Index; D016535:Bronchial Hyperreactivity / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D009765:Obesity / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D012044:Regression Analysis; D012135:Respiratory Sounds / Q000503:physiopathology; D012307:Risk Factors; D014028:Tobacco Smoke Pollution; D014797:Vital Capacity / Q000502:physiology
D014028:Tobacco Smoke Pollution