Twenty-two of 81 participants had asthma and obstructive sleep apnea over the first four year follow-up. Patients with asthma experienced five incident OSA cases during 167 four-year intervals (27 percent), and participants without asthma experienced 160 incident OSA cases during 938 four-year intervals (17 percent).
The authors wrote, “This study prospectively examined the relationship of asthma with OSA assessed with laboratory-based polysomnography and found that preexistent asthma was a risk factor for the development of clinically relevant OSA in adulthood over a four-year period. Furthermore, the asthma-OSA association was significantly dose-dependent on duration of asthma. Studies investigating the mechanisms underlying this association and the value of periodic OSA evaluation in patients with asthma are warranted.”
Asthma is a risk factor for obstructive sleep apnea: Previous study
Researchers from the University of Wisconsin have identified asthma as a risk factor for obstructive sleep apnea. They used data from the Wisconsin Sleep Cohort Study, which followed nearly 1,500 subjects since 1988. Patients with asthma were 1.70 times more likely to develop obstructive sleep apnea, compared to individuals without the breathing condition.
Lead researcher Mihaela Teodorescu said, “This is the first longitudinal study to suggest a causal relationship between asthma and sleep apnea diagnosed in laboratory-based sleep studies. Cross-sectional studies have shown that OSA is more common among those with asthma, but those studies weren’t designed to address the direction of the relationship.”
The link between asthma and obstructive sleep apnea was even greater in individuals who developed asthma as children. The risk of obstructive sleep apnea from childhood-onset asthma was 2.34 times greater.
During the eight-year follow-up, 45 participants developed asthma and were 48 percent more likely to develop obstructive sleep apnea as well.
Principal investigator Paul Peppard said, “Forty-eight percent represents a large difference. This is one result that calls for a follow-up study. If confirmed by a larger study with more asthma cases, the finding would have important clinical relevance”
“For now, it makes sense for clinicians to consider asthma history, as well as more traditional factors associated with OSA such as obesity, when deciding whether to evaluate patients for OSA with a sleep study,” Dr. Peppard continued.
Additional research on child cohorts could be particularly beneficial in future studies of asthma and obstructive sleep apnea, as the strongest association was seen in those with childhood asthma.