Background: Epigenetic mechanisms may alter the airway epithelial barrier and ultimately lead to atopic diseases such as asthma. Here we aim to identify DNA methylation profiles that are associated with-and accurately classify-atopy and atopic asthma in school-aged children.

Obesity is detrimental to lung function, but specific patterns differ between children and adults. Physicians should be aware of adverse effects of obesity on lung function, and weight control should be considered in the management of airway disease among the obese.

Background Obesity increases the risk of asthma and asthma severity and is a well-known risk factor for insulin resistance and the metabolic syndrome (MS) in children and adolescents. Objective We aim to examine the association among obesity, insulin sensitivity, metabolic syndrome, and lung function in U.S. adolescents with and without asthma. Methods Cross-sectional study 1,429 adolescents aged 12–17 years in the 2007–2010 National Health and Nutrition Examination Survey. Adjusted regression was used to assess the relationships among obesity, insulin sensitivity/resistance, metabolic syndrome, and lung function in children with and without asthma. Results Insulin resistance was negatively associated with FEV1 and FVC in adolescents with and without asthma, while MS was associated with lower FEV1/FVC, with a more pronounced decrease among asthmatics; these associations were driven by overweight/obese adolescents. Higher BMI was associated with a decrease in FEV1/FVC among adolescents with insulin resistance. Compared to healthy participants, adolescents with MS had a ~2% decrease in FEV1/FVC; adolescents with asthma had a ~6% decrease; and those with MS and asthma had ~10% decreased FEV1/FVC (p<0.05). Conclusion Insulin resistance and MS are associated with worsened lung function in overweight/obese adolescents. Asthma and MS synergistically decrease lung function, as do obesity and insulin resistance. These factors may contribute to the pathogenesis of asthma severity in obese patients and warrant further investigation.