Sleep Apnea is Associated with Heart Disease in Large University of Wisconsin Study

When a study follows a particular demographic or statistical group, that study can be considered a cohort study. One carefully followed group is the Wisconsin Sleep Cohort. The Department of Medicine, and the University of Wisconsin has been following this cohort for over 20 years. I was fortunate to attend my residency at the University of Wisconsin and to meet some of the researchers who are still actively involved in this project.

[“Sleep Disordered Breathing and Mortality: Eighteen-Year Follow-up of the Wisconsin Sleep Cohort”, Young, Terry PhD, et al., Department of Population Health Sciences and Department of Medicine, University of Wisconsin-Madison, Madison, WI. SLEEP, Vol 31, No. 8, 2008.]

When the researchers wrote their 18^th year report and released it to SLEEP Journal it was released for expedited publication. The cohort sample includes 1522 adults assessed at baseline for sleep disordered breathing/sleep apnea and stratified as mild, moderate, and severe sleep apnea. All-cause mortality risk was adjusted for confounding factors such as age, gender, weight (body mass index), other disease states, etc that could have affected the results.

The researchers found startling results. People with severe untreated sleep apnea had a 3.8 times greater chance of dying than the baseline population without sleep apnea. They also had a 5.2 times greater chance of dying of cardiovascular disease. These people did not necessarily have current cardiovascular disease or other cardiovascular risk factors.

Moderate sleep apnea conveyed an overall 1.7 times greater risk. Mild sleep apnea conveyed a 1.4 times greater risk.

These findings were significant and were consistent with other important studies like the Sleep Heart Health Study.

Patients at the Swedish Sleep Medicine Associates Clinics get a thorough evaluation. If they are found to have sleep apnea they are advised to get treatment and to consistently adhere to their treatment plan in order to eliminate symptoms of sleep apnea such as daytime sleepiness, snoring, loss of mental acuity. They are also told that treating sleep apnea also has the critically important role of reducing cardiovascular risk.

Darius Zoroufy