Overweight men suffering obstructive sleep apnoea can find relief for their problem with weight loss, a new study has revealed.
Obstructive sleep apnea (OSA) is a common sleep apnea caused by the collapse of the upper airways during sleep. It is characterized by pauses in breathing during sleep. Each episode (apnoea) lasts for at least 10 seconds.
Moderate and severe obstructive sleep apnoea (defined as 15 or more apnoeas per hour) carries an excess risk of motor vehicle crashes, heart disease and death. Yet only one study has examined the effects of weight loss on obstructive sleep apnoea.
Now, researchers at the Karolinska Institute in Sweden have evaluated if treatment with a low energy diet reduces moderate and severe obstructive sleep apnoea in obese men.
The study involved 63 obese men (BMI 30-40) aged 30-65 years with moderate to severe obstructive sleep apnoea who were being treated with continuous positive airway pressure (a mask designed to help breathing during sleep).
Thirty men received a liquid very low energy diet for seven weeks to promote weight loss, followed by two weeks of gradual introduction of normal food. The remaining men acted as a control group by adhering to their usual diet over the nine weeks.
At the beginning of the study, both groups had a mean apnoea hypopnoea index (AHI) of 37 apnoeas per hour. At week nine, the diet group had a mean AHI of 12 events per hour compared with 35 events per hour in the control group, the researchers found.
The results also showed that the diet group lost an average of 18.7 kg in weight compared with 1.1 kg in the control group over the nine-week period. 22 out of 30 patients in the diet group were no longer obese at the end of the study, whereas all control patients remained obese.
Apart from that, the researchers also found that five out of 30 patients in the diet group were also disease-free by the end of the study, and half had only mild disease, whereas all patients in the control group except one still had moderate to severe disease.
The researchers concluded that treatment with a low energy diet improves obstructive sleep apnoea in obese men, with the greatest effect in patients with severe disease.
The study has been published on bmj.com.