Abstract
STUDY OBJECTIVES: Both asthma and obstructive sleep apnea (OSA) are strongly associated with poor sleep. Asthma and OSA also have several features in common, including airway obstruction, systemic inflammation, and an association with obesity. The aim was to analyze the effect of asthma, OSA, and the combination of asthma and OSA on objectively measured sleep quality and systemic inflammation. METHODS: Sleep and health in women is an ongoing community-based study in Uppsala, Sweden. Three hundred eighty-four women ages 20 to 70 years underwent overnight polysomnography and completed questionnaires on airway diseases and sleep complaints. C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor α were analyzed. RESULTS: The group with both asthma and OSA had higher CRP, higher IL-6, a longer sleeping time in stage N1 sleep and stage N2 sleep, and less time in stage R sleep than the control group with no asthma or OSA. The group with both asthma and OSA had lower mean oxygen saturation (93.4% versus 94.7%, P = .04) than the group with OSA alone. The results were consistent after adjusting for age, body mass index, and smoking status. Asthma was independently associated with lower oxygen saturation, whereas OSA was not. CONCLUSIONS: Our data indicate that coexisting asthma and OSA are associated with poorer sleep quality and more profound nocturnal hypoxemia than either of the conditions alone. The results are similar to earlier findings related to OSA and chronic obstructive pulmonary disease, but they have not previously been described for asthma.