Asthma prevalence trends by weight status among US children aged 2-19 years, 1988-2014

Background: Obesity is a risk factor for asthma. However, it is unclear if increased obesity prevalence contributed to rising childhood asthma prevalence. Objective: To assess if population-level changes in weight status impacted asthma prevalence over time. Methods: Using nationally representative 1988-2014 National Health and Nutrition Examination Survey data for 40 644 children aged 2-19 years, we analyzed asthma trends by weight status (body mass index age-specific percentiles determined using measured weight and height). Logistic regression and population attributable fraction were used to assess the association between obesity and asthma prevalence. Results: Although obesity was a risk factor for asthma throughout the period, asthma prevalence increased only among children with normal weight; there was no interaction between weight status and time. The population attributable fraction for overweight/obesity rose from 8.5% in 1988-1994 to 11.9% in 2011-2014, but this increase was not significant (P = 0.44). Conclusions: Together, these data do not support a contribution of obesity trends to asthma prevalence trends.