Sleep duration, asthma and obesity

Abstract

Background: Obesity is more prevalent in asthmatics. Sleep duration is a novel risk factor for obesity in general populations. Objective: We tested the association of sleep duration and asthma characteristics with obesity. Methods: Adults at tertiary clinics were surveyed on asthma symptoms and habitual sleep duration. Medical records were used to assess asthma severity step (1–4), extract height and weight, current medications and diagnosed comorbid conditions. BMI ≥30 kg/m² defined obesity. Habitual sleep was categorized as <6 (very short), 6 to <7 h (short), 7–8 h (normal), >8 to ≤9 h (long) and >9 h (very long). Inhaled corticosteroid doses were categorized as low, moderate and high. Results: Among 611 participants (mean BMI 30 ± 8), 249 (41%) were obese. After adjustment for covariates, obesity was associated with short and very long sleep: as compared to normal sleepers, the odds of being obese were on an average 66% higher ([95% CI: 1.07–2.57], p = 0.02) among short and 124% higher ([1.08–1.65], p = 0.03) among very long sleepers, and the association with very short sleep approached significance (1.74 [0.96–3.14], p = 0.06). Obesity was also significantly related to highest asthma step (1.87 [1.09–3.21], p = 0.02) and psychopathology (1.64 [1.08–2.48], p = 0.02), and a trend was seen with high-dose inhaled corticosteroids (1.82 [0.93–3.56], p = 0.08). Conclusions: Obesity in asthmatics is associated with shorter and very long sleep duration, worse asthma severity, psychopathology and high-dose inhaled corticosteroids. Although this cross-sectional study cannot prove causality, we speculate that further investigation of sleep may provide new opportunities to reduce the rising prevalence of obesity among asthmatics.

• Obesity
• mechanisms

Acknowledgements

The authors are grateful to study subjects for their participation. We wish to acknowledge Carolyn M. Senger, Radu C. Nistor, Jesica M. Pedroza, Ashley S. Holland, Stephanie V. Hall, Whitney Stalsberg, Roman Aydiko and Padau Yang, for their assistance with administration of screening surveys. We recognize the help from the providers and staff at the Pulmonary Clinics and Briarwood Asthma-Airways Center at the University of Michigan – Ann Arbor, and Allergy and Pulmonary Clinics at the University of Wisconsin – Madison for subject recruitment.