People with sleep apnea appear to be at higher risk of pneumonia than people without, according to a study published in Canadian Medical Association Journal (CMAJ).

To determine whether sleep apnea is linked to the development of pneumonia, Taiwanese researchers followed 34,100 patients (6,816 who had sleep apnea and 27,284 controls) for 11 years. They found that pneumonia was more likely to develop in the people with sleep apnea than in the control group (638 [9.36%] vs 2,119 [7.77%]). The people with pneumonia were older and had more comorbidities such as heart disease, diabetes, dementia, and other diseases.

“This study showed that sleep apnea is an independent risk factor for incident pneumonia,” says Dr Vincent Yi-Fong Su and Dr Kun-Ta Chou, Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, with coauthors, in a release. “Our results also demonstrated an exposure–response relation in that patients with more severe sleep apnea may have a higher risk of pneumonia than patients with sleep apnea of milder severity.”

Several studies have explored the link between sleep apnea and pneumonia, although they have been smaller than this large cohort study.

The authors suggest that the higher incidence of pneumonia in people with sleep apnea could be because of increased risk of aspirating contents or liquid from the throat.