Obesity, low levels of physical activity and smoking present opportunities for primary care asthma interventions: an analysis of baseline data from The Asthma Tools Study

BACKGROUND: Asthma prevalence, severity and outcomes are associated with various patient characteristics and lifestyle choices. AIMS: To identify potentially modifiable factors associated with poor asthma outcomes among US primary care patients. METHODS: Using baseline data from the Asthma Tools Study, we calculated cross-sectional frequencies of activity levels, smoking, secondhand smoke exposure and the presence of obesity, as well as rates of out-of-control asthma and asthma exacerbations. Frequencies were stratified by sex, and into three age groups: 5–11 years, 12–18 years and 19 years and older. Logistic regression was used to identify factors associated with each of the asthma outcomes. RESULTS: In the 901 individuals enrolled in this asthma study, tobacco smoke exposure, obesity, low activity levels, poverty, inadequately controlled asthma and high asthma-related health-care utilisation were common. Across all age groups, obesity was associated with poorer asthma outcomes: either poor asthma control (odds ratio (OR)=2.3, 95% confidence interval (CI) 1.1–4.7 in 5- to 11-year-olds and OR=1.5, 95% CI 1.1–2.2 in adults) or asthma exacerbations (OR 2.9, 95% CI 1.6–5.1 in 12- to 18-year-olds and OR 1.7, 95% CI 1.1–2.5 in adults). Among adults, smoking was associated with both measures of poorer asthma outcomes; inadequate asthma control (OR=2.3, 95% CI 1.5–3.5), and asthma exacerbations (OR 1.7, 95% CI 1.1–2.6), and low physical activity were associated with poor asthma control (OR=1.5, 95% CI 1.1–2.2). CONCLUSIONS: Obesity, low levels of physical activity and smoking are common, and they are associated with poor asthma outcomes in a sample of primary care patients, suggesting important targets for intervention.