Asthma patients have an increased risk of developing obstructive sleep apnoea, with the link stronger with having had asthma longer, according to a US study.
Although a few studies have suggested an association between the two, it has previously been unknown whether asthma is a causal risk factor for obstructive sleep apnoea, said researchers.
A team from the University of Wisconsin School of Medicine and Public Health examined the relationship between asthma and new cases of obstructive sleep apnoea in an ongoing study of 30-60 years olds.
The authors found 22 out of 81 participants (27%) with asthma developed obstructive sleep apnoea over the first four-years of the study, compared to 75 of 466 people (16%) without asthma.
“This study… found that pre-existent asthma was a risk factor for the development of clinically relevant obstructive sleep apnoea in adulthood over a four-year period,” they said.
“Furthermore, the association was significantly dose-dependent on duration of asthma,” said the authors in the Journal of the American Medical Association.
They added: “Studies investigating the mechanisms underlying this association and the value of periodic obstructive sleep apnoea evaluation in patients with asthma are warranted.”