Weight loss has been proven to be a key cause of obstructive sleep apnea (OSA). I have written previously on the research from Richard Schwab, MD at the University of Pennsylvania, showing that the connection appears to be related to fat storage (and likely muscle mass too) in the head and neck.
This work is fascinating but does not address the question that patients ask me all the time: “How much weight loss do I need to improve my sleep apnea?” The largest studies that attempted to provide an answer followed individuals over time, with sleep studies spaced out a few years apart. They took advantage of the fact that some people gained and some people lost weight naturally, allowing them to compare the results of the sleep studies before and after weight gain and weight loss. In general, a 10% gain in body weight was associated with a 40% worsening in OSA, whereas a 10% weight loss improved OSA severity by 25-30%.
Not so fast. The reality is that these studies mainly included individuals without OSA, for example, having someone with an apnea-hypopnea index go from 4.0 to 3.0 with a 10% weight loss. That is just not meaningful for anyone, let alone my patients.
Many studies that have explored the connection between weight loss and changes in OSA with interventions to target weight loss like medications and surgery. However, this month in the Journal of Clinical Sleep Medicine, a Greek team analyzed data from the MIMOSA randomized trial of Mediterranean dietary/lifestyle changes for managing moderate to severe OSA in overweight or obese adults (body mass index greater than 25 kg/m2). They did not compare different interventions but focused on the association between weight loss (regardless of intervention group) and OSA improvement in the 127 study participants who did lose weight. The studies showed that:
- Weight loss of <5% was associated with an OSA improvement of 12%
- Weight loss of 5-10% was associated with an OSA improvement of 38%
- Weight loss of >10% was associated with an OSA improvement of 49%
These results are important and encouraging news for patients who are pursuing weight loss, as they suggest greater improvements in OSA than seen in most previous studies. Of course, this study is relatively small, but it did include those patients who are exactly like those whom I see all the time in my practice.
Weight loss is an important OSA treatment itself, but it can also improve OSA and enhance the results of other treatments like surgery or oral appliances. We do need to keep in mind that weight loss can be extremely difficult for those with OSA, for multiple reasons including the fact that these patients are often tired or fatigued (limiting their ability to exercise) and may have some changes in appetite and metabolism. Nevertheless, this study highlights its importance and value as part of a holistic approach to managing OSA.