CPAP and weight

Elevated weight contributes to obstructive sleep apnea (OSA). Some studies even suggest that OSA can contribute to elevated weight. Many of my patients know this and hope that they may lose weight by treating their OSA. This study is part of a larger one that examined the effect of CPAP therapy on neurocognitive functioning in patients with OSA. CPAP usage was monitored by the CPAP device - so the researchers knew if the patient was actually using CPAP enough. The researchers randomly assigned participants to either real CPAP or sham (fake) CPAP. The results showed that participants on real CPAP gained weight over six months, whereas those on the sham CPAP lost weight over the same time period. And interestingly, weight gain was greater the more the participant used the real CPAP per night. This effect was not seen in those on the sham CPAP. Finally, the results were independent of age, gender, race, OSA severity, and sleepiness.

Keep in mind that we are talking about small changes in weight - The real CPAP users, on average, gained less than one pound at the six month mark. And the sham CPAP users, on average, lost about 1.5 pounds during the same six months. The study authors do not know the reason for the weight increase in real CPAP users. They postulated that perhaps people with OSA burn more calories when they sleep due to the effects of stopping breathing - and that treating the OSA with real CPAP can mitigate that effect. I'm not sure I buy that argument. More studies will certainly be needed.

Bottom line - CPAP therapy is not a weight loss treatment - if it were, compliance would be much better and I would have a line of people outside my office wanting to get CPAP. But adherence to CPAP therapy is low and CPAP won't make people lose weight. Weight loss is achieved only with dietary change and exercise.

Systems of obstructive sleep apnea and cancer risk

There have not been many studies looking at an association between obstructive sleep apnea and cancer. It's possible that obstructive sleep apnea theoretically could increase risk of cancer due to inflammatory changes, oxidative stress, possible immune dysfunction, and intermittent low oxygen levels. This study with a large population from Denmark with purple work or study. The researchers assessed possible obstructive sleep apnea by asking him questions about snoring, stopping breathing while asleep, and subjective daytime sleepiness. No subsided for performed, so short of sleep apnea was not officially diagnosed or ruled out in this population. The researchers then compared the incidence of developing cancer with the obstructive sleep apnea symptoms.

The results did not show any significant association between snoring, history of stopping breathing while asleep, or sleepiness with incidence of cancer. However, as reviewed in the article, assessing for the presence of obstructive sleep apnea by just asking patients about their symptoms is not all that accurate. It would be better for these patients to have had sleep studies to actually determine if obstructive sleep apnea was present.

This study does not support a strong association between obstructive sleep apnea symptoms and risk of cancer. More studies need to be undertaken to determine if an actual diagnosis made from a sleep study is associated with elevated risk of developing cancer. And then whether or not treating the obstructive sleep apnea reduces that risk.

Eexercise and sleep

Exercise has been shown to improve sleep quality. This study was looked at the relationship between physical activity and subjective and objective sleep in midlife women. Physical activity was assessed with questionnaires and the level of activity was split into 3 domains. The first domain was labeled Active / Living and consisted of things like watching television and active transportation such as walking to work. The second domain was Household / Care-giving activities such as housework and child care. The last domain was Sports / Exercise which included participation in recreational activity or sports. The women's sleep was measured via in-home sleep study, daily sleep diaries, and questionnaires about their sleep.

The results showed that women who consistently participated in regular Sports / Exercise had better objective and subjective measurements of sleep, including sleep quality, sleep continuity, and depth, but not sleep duration. Women in this group also had reduced odds of meeting the diagnostic criteria for insomnia. This relationship was observed despite statistical adjustment for factors such as body mass index and other health behaviors. This association was not seen for those women in the domains of Active / Living and Household / Care-giving.

The relationship between the Sports / Exercise group and sleep was strongest when the pattern of activity existed over multiple years rather than just exercising immediately prior to the sleep assessment. In other words, regular exercise over many years may improve sleep more than sporadic exercise.

The effects of sleep deprivation on facial appearance

This article received lots of press. Researchers took photographs of subjects after 8 hours of normal sleep and after 31 hours of sleep deprivation following only 5 hours of sleep the night before. The researchers then asked volunteers to list facial cues they associate with looking fatigued. The final list consisted of hanging eyelids, red eyes, swollen eyes, glazed eyes, dark circles under the eyes, pale skin, wrinkles around the eyes, rash / eczema, and droopy mouth corners. Finally, the researchers had participants rate the photographs for the fatigue cues.

The results showed that the fatigue cues were significantly found in the photographs of sleep deprived subjects - no big surprise. With the exception of glazed eyes, all of the cues that correlated with looking fatigued were also affected by sleep deprivation.

This research is interesting in that these cues for fatigue may help others determine if someone is too fatigued to be safe at work or while driving.

Improvement in facial appearance after CPAP treatment for obstructive sleep apnea

Here is an interesting article about changes in facial appearance after CPAP treatment for obstructive sleep apnea (OSA). Researchers took 20 subjectively sleepy subjects diagnosed with OSA but not treated. They took detailed photographs using specialized digital photography techniques before and after several months of CPAP treatment. They then had 22 raters look at the before and after treatment photos to assess which ones were post-treatment and what changes were present.

The results showed that treatment with CPAP is rated as more alert, more youthful, and more attractive than before CPAP use. In this study, the researchers had the subjects subjectively rate their level of sleepiness. As expected, sleepiness levels did improve overall. However, there was not a strong correlation between the person feeling more alert and being perceived more alert by the raters. This may be because the subjective scale for sleepiness is limited, and perhaps an objective measure of sleepiness may have correlated better.

Finally, the results did not support the popular belief that dark, swollen, and baggy circles under the eyes are a main feature of sleepiness in those with OSA. Of course, it could be a feature in those who are sleepy from other causes, like sleep deprivation.

Since adherence to CPAP is not great, perhaps the results of this study will provide more motivation for individuals to use their CPAP regularly.