Assessing the association of obesity and asthma morbidity in older adults

Background Obesity is a robust predictor of poor asthma control in younger adults. Given the high prevalence of asthma and obesity in older Americans, weight reduction could benefit asthma management in this population. Objective To assess the association between obesity and asthma outcomes among older adults. Methods We recruited from urban primary care clinics a prospective cohort of nonsmoking individuals with asthma who were 60 years or older without a history of other respiratory diseases. At baseline, body mass index (BMI) measurements were classified as normal (BMI, 18–25), overweight (BMI, 25–30), or obese (BMI, >30). Measures of asthma morbidity (Asthma Control Questionnaire [ACQ], and Mini Asthma Quality of Life Questionnaire [Mini-AQLQ]) and asthma-related resource utilization (inpatient or outpatient) were taken at baseline and at 3- and 12-month interviews. We used generalized estimating equation models to assess associations between obesity and asthma outcomes after controlling for potential confounders. Results Of the 437 older adults with asthma in the study, 17% had a normal BMI, 32% were overweight, and 51% were obese. Unadjusted analyses revealed that obesity was associated with lower ACQ scores (odds ratio [OR], 1.19; 95% confidence interval [CI], 1.09–1.31) and poorer Mini-AQLQ scores (OR, 1.21; 95% CI, 1.11–1.33). Adjusted analyses revealed no significant association between obesity and ACQ (OR, 1.05; 95% CI, 0.96–1.15) and Mini-AQLQ (OR, 1.08; 95% CI, 0.99–1.19). Conclusion Our study suggests that obesity is not independently associated with worse asthma outcomes in older adults, reflecting potential differences in the mechanisms that link obesity with asthma control in older vs younger populations.