BACKGROUND: Asthma burdens more than 25 million people in the United States. Additionally, 69% of adults and 32% of youth in the U.S. are overweight or obese. Among overweight/obese individuals, asthma symptoms are generally more severe and difficult to control. Approximately 80% of pediatric asthma is atopic, with patients demonstrating allergic symptoms. Current literature acknowledges the presence of an obese asthma phenotype, though it is unknown as to whether asthma in obese individuals is atopic or related to overweight/obesity. The goal of this study was to examine whether aeroallergen sensitization is related to increased body mass index (BMI) in Nevadan pediatric asthmatics.
METHODS: BMI status, skin prick test results for sensitization to more than 60 potential aeroallergens, and other variables were obtained from medical records from a pediatric allergy clinic in Nevada. Data analysis included descriptive statistics to characterize the population regarding asthma severity, allergen sensitization, and BMI status. Binary logistic regression was conducted to examine the likelihood of allergen sensitization for each BMI category while controlling for age, sex, and race.
RESULTS: The population included 125 patients aged 1-16 years (median=7.0 years), of whom 61% were male (n=76), 65% were white (n=81), and 66% had a healthy weight BMI (n=82). Nearly 85% of the children had moderate or severe asthma (n=105), 82% were sensitized to at least one allergen (n=102), and 75% were sensitized to 3+ allergens (polysensitized) (n=94). The logistic regression model demonstrated that BMI and age were significant predictors of allergen sensitization. Those who were overweight were 79.2% less likely to be sensitized to allergens than those who were of healthy weight (OR 0.208, p=0.01, 95% CI=0.063-0.689). Those who were obese were also less likely to be sensitized, but findings were not significant statistically (p=0.407). For every year that age increased, patients had 28% greater odds of being sensitized to allergens (OR 1.27, p=0.01, 95% CI=1.08-1.54).
CONCLUSIONS: This study found overweight, but not obesity, to be a protective factor for aeroallergen sensitization among this population of asthmatic youth. Increased age was associated with increased allergen sensitization. Research regarding asthma and allergic diseases in overweight/obese children is scarce. These results may provide some insight for other researchers and clinicians into asthma risk factors among overweight and obese youth, especially in Nevada, where children become sensitized to aeroallergens early in life and at a high rate.