Researchers in Norway evaluated the association between obstructive sleep apnea and other health conditions such as hypertension, COPD, diabetes, and obesity.
Obstructive sleep apnea (OSA) is a sleep disorder characterized by brief interruptions or pauses in breathing during sleep. One common cause of the obstruction is the relaxation of the muscles during sleep which allows the soft tissue in the airway to collapse. While many people may experience brief episodes of OSA at some point in their lives, only about 15% of sufferers are afflicted with severe OSA.
Since individuals with obstructive sleep apnea are rarely aware of these interruptions, they may suffer from OSA for years without a diagnosis. Daytime drowsiness and fatigue are often attributed to other factors. As a result, the overall effect of obstructive sleep apnea on the body over time is not well understood.
In a recent study published in PloS ONE, researchers from Bergen, Norway investigated whether severe sleep apnea was associated with higher risk for heart attack, angina, stroke, chronic obstructive pulmonary disease (COPD), high blood pressure, diabetes, asthma, or obesity.
A total of 1,887 people who suspected they might have sleep apnea were recruited to participate in this study between 2011 and 2014. Seventy percent of the participants were men and the average age was 48.6 years. Each person underwent a sleep study to assess whether they had OSA and if so, how severe it was. Apneas were defined as a reduction of 90% or more of baseline nasal airflow lasting for at least ten seconds. In addition, their sex, weight, height, and blood pressure values were recorded. Lastly, each participant filled out a questionnaire asking whether they had any known health conditions.
They found that although all of the participants had been referred on suspicion of having sleep apnea, 38% did not have sleep apnea, 30% had mild apnea, 17% had moderate apnea, and 15% had severe apnea. They also found that the severity of obstructive sleep apnea was associated with a higher prevalence of heart attack, angina pectoris, and diabetes. Obesity and hypertension were most strongly correlated with the severity of the apnea. There was no association between sleep apnea and stroke, COPD, or asthma.
Surprisingly, there was a negative association between smoking and apnea severity. The researchers felt that this finding may be explained by the relative ease for doctors to discuss smoking health risks and smoking cessation compared to the apnea. The large sample size and use of both logistic and linear regression add credence to these results; however, we cannot stipulate whether obstructive sleep apnea precedes or develops as a result of the other conditions.
Written by Debra A. Kellen, PhD
Reference: Tveit, R. L., Lehmann, S., & Bjorvatn, B. (2018). Prevalence of several somatic diseases depends on the presence and severity of obstructive sleep apnea. PloS one, 13(2), e0192671. https://doi.org/10.1371/journal.pone.0192671