For every five years that a person has asthma the risk of developing sleep apnea raises by 10 % – according to a research conducted by researchers at the University of Wisconsin . The research was funded by the National Institutes of Health . About 773 participants were studied and followed up for eight years after joining the study group in 1988. The age of the participants were between 30-60 years of age.
“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.”
However these results would not be considered conclusive in establishing “causality” between asthma and sleep apnea because of the size of the group.
For more details read http://medicalxpress.com/news/2013-05-potential-apnea-asthma.html