Obstructive sleep apnoea syndrome is common in subjects with chronic bronchitis. Report from the Obstructive Lung Disease in Northern Sweden studies

Background: In previous studies we have found that subjects with bronchitis have a higher prevalence of 'snoring as a problem' than respiratory healthy subjects.

Objectives: We aimed to study whether the high prevalence of snoring among subjects with bronchitis also represents a high prevalence of obstructive sleep apnoea (OSA).

Method: Subjects in three age groups born 1919-1920, 1934-1935 and 1949-1950 had been identified as bronchitic in an earlier study (n = 471) and without respiratory symptoms (n = 108). Of the 91 subjects reporting snoring to be a problem, 70 were invited to participate in the study. Sleep investigation was performed in 52 of these 70 subjects.

Results: 'Snoring as a problem', predicted OSA to a similar degree in both bronchitic and respiratory healthy subjects. The estimated prevalence for obstructive sleep apnoea with an apnoea/hypopnoea index (AHI) 10 as the cut-off point and concomitant daytime symptoms such as daytime sleepiness or liability to nodding off during breaks in activity in the daytime, was 5.4% for bronchitic subjects and 2.3% for respiratory healthy subjects. Apnoea in addition to snoring predicted OSA better than did snoring alone. Age correlated significantly with AHI, and OSA was most common in the middle-aged group, 61-62 years old.

Conclusion: OSA is twice as common in subjects with chronic bronchitis as in subjects free of pulmonary disease or symptoms.