Umeå universitets logga

Background: Obstructive sleep apnea is a common disorder, especially in men. Patients with this condition often snore and suffer from excessive daytime sleepiness. It is a treatable condition related to cardiovascular disease, road traffic accidents and obesity.

Aims: To study whether snoring and witnessed sleep apnea are related to diabetes mellitus and whether sleepy subjects who snore or report sleep apneas drive more than others. To investigate whether sleep apnea is related to stroke, mortality and myocardial infarction in patients with coronary artery disease. To study the effect of ambient temperature on sleep apnea, morning alertness and sleep quality in patients with obstructive sleep apnea.

Methods and results: Questions on snoring, sleep apnea, daytime sleepiness and yearly driving distance were included in the northern Sweden component of the WHO MONICA study. Analyzed were 7905 randomly selected men and women aged 25-79 years. Snoring and witnessed sleep apnea were related to diabetes mellitus in women, (OR 1.58, p = 0.041 and OR 3.29, p = 0.012 respectively), independent of obesity, age and smoking, but not in men. Sleepy snoring men drove a mean of 22566 km per year which was more than others who drove 17751 km per year independent of age, BMI, smoking and physical activity (p = 0.02). Sleepy men reporting sleep apnea also drove more (p = 0.01). 392 men and women with coronary artery disease referred for coronary angiography were examined with overnight sleep apnea recordings and followed for 10 years. Sleep apnea was recorded in 211 (54%) of patients at baseline. Stroke occurred in 47 (12%) patients at follow up. Sleep apnea was associated with an increased risk of stroke (HR 2.89, 95% CI 1.37 - 6.09, p = 0.005) independent of age , BMI, left ventricular function, diabetes mellitus, gender, intervention, hypertension, atrial fibrillation, a previous stroke or TIA and smoking. The risk of stroke increased with the severity of sleep apnea. 40 patients with obstructive sleep apnea were investigated with overnight polysomnography in ambient temperatures of 16°C, 20°C and 24°C in random order. Total sleep time was a mean of 30 minutes longer (p = 0.009), sleep efficiency higher (p = 0.012), patients were more alert in the morning (p = 0.028), but sleep apnea was more severe when sleeping in 16°C (p = 0.001) and 20°C (p = 0.033) vs. 24°C. The AHI was 30 ± 17 in 16ºC room temperature, 28 ± 17 in 20°C and 24 ± 18 in 24°C.

Conclusions: Snoring and witnessed sleep apneas are related to diabetes mellitus in women. Sleepy men who snore or report sleep apnea drive more than others. Sleep apnea is independently associated with the risk of stroke among patients with coronary artery disease. Subjects with obstructive sleep apnea sleep longer, are more alert in the morning after a night’s sleep, but sleep apnea is more severe when sleeping in a colder environment.