A review of obesity and asthma across the life span

Objective: This literature review aims to compare obese-asthmatic adults and children, and to characterize differences and similarities between the two subgroups from epidemiological, demographical, phenotypical, and physiological perspectives. Methods: Literature search was conducted using Pubmed database with "obesity," "asthma," "epidemiology," "cluster analysis," "demography," "mechanics," and "FeNO'' as search terms. Methods: Articles investigating epidemiological, demographic, phenotypical variation, and mechanical aspects of breathing specifically in obese asthmatics were identified. The studies were then divided according to age: children (<18 years of age) and adults (>18 years of age). Results: Increase in asthma incidence and prevalence is observed in both obese-asthmatic children and adults. Asthma prevalence is greater in adult females regardless of ethnic background, and in men of African American and Hispanic ethnicities. Degree of weight gain and early onset of menarche appears to directly affect asthma severity in adolescent girls and females. Airway hyperresponsiveness and fractional exhaled nitric oxide do not have any positive correlation with high BMI in obese-asthmatic children and adults. Obesity also alters lung mechanics in asthmatics, but the impact is different for children and adults likely due to differential effect of obesity on central and peripheral airway. Conclusion: Existing literature suggests both similarities and differences in obese-asthmatic children and adults. The most pertinent differences are related to gender, ethnicity, and lung functions.