Obesity, type 2 diabetes, and obstructive sleep apnea (OSA) occur together commonly. Weight reduction has been shown to improve both blood sugar control and OSA severity. There is a study that looked at intensive lifestyle intervention (ILI) versus usual diabetic support (DS) in OSA severity. After one year, the ILI group had greater weight reductions and less severe OSA than the DS group. The researchers then looked at the results after 3 more years, as reported in this paper.
So after the first year, the intensive lifestyle intervention was provided on an individual basis and included one on-site visit per month. There was a second contact by telephone, regular mail, or email. At each session, participants were weighed, self-monitoring records reviewed, and a new lesson presented. The usual diabetes support group had three annual sessions, with each one focusing on diet, physical activity, and social support. Information on behavioral strategies was not presented and participants were not weighed, like in the ILI group.
Results showed that at year 4, >5 times as many participants in the ILI group had total remission of their OSA. The prevalence of severe OSA among ILI group was half that of the diabetes support group. OSA remission occurred in those with mild to moderate OSA at baseline. But in those with severe OSA at baseline, none achieved remission and few changed to mild severity. And in both groups, a similar prportion had a worsening of OSA severity at year 4. Some had mild OSA at baseline and then severe OSA at year 4! A limitation of this study is that almost 38% of participants dropped out by year 4, primarily due to not wanting to repeat PSG.
So what does all this mean? That if you have severe OSA, weight reduction alone is unlikely to get rid of the OSA. However, weight reduction alone may eliminate OSA that is mild to moderate.