Sleep Restriction Leads To Less Fat-Loss

Regular readers will be well aware of the increasing data supporting the importance of adequate restorative sleep on metabolism and weight management. Now, a study by Wang Xuewen and colleagues, published in SLEEP, shows just how detrimental sleep deprivation can be during a weight-loss diet. Their study included thirty-six 35-55 years oldadults with overweight or obesity, who were randomized to an 8-week caloric restriction (CR) regimen alone (n=15) or combined with sleep restriction (CR+SR) (n=21). All participants were instructed to restrict daily calorie intake to 95% of their measured resting metabolic rate. Participants in the CR+SR group were also instructed to reduce time in bed on 5 nights and to sleep ad libitum on the other 2 nights each week. The CR+SR group reduced sleep by about 60 minutes per day during sleep restriction days, and increased sleep by 60 minutes per day during ad libitum sleep days, resulting in a sleep reduction of about 170 minutes per week.Although both groups lost a similar amount of weight during the study ~3 Kg). However, the proportion of total mass lost as fat was significantly greater  in the CR group (80% vs. 16%). In line with this substantial difference in fat reduction, resting respiratory quotient was significantly reduced only in the CR group. Importantly, these effects of sleep deprivation on fat loss were observed despite the fact that subjects were allowed to sleep as much as they wanted on the non-restricted days. This suggests that the negative effects of sleep deprivation during weight loss are not made up by “make-up” sleep. Although overall, the amount of weight lost in this study is modest, it clearly fits with the notion that adequate sleep (in this case, during weight loss), can be an important part of weight management. Clearly, the role of sleep in energy homeostasis will remain an interesting field of research, as we continue learning more about how sleep (or rather lack of it) affects metabolism. @DrSharma Edmonton, AB

Diagnosis and Treatment of Obstructive Sleep Apnea in Adults

In follow up to yesterday’s guest post by Christy Turer on her challenges in getting timely diagnostics and treatment for a patient with severe obstructive sleep apnea (OSA), it appears timely that this week’s issue of the Canadian Medical Association Journal (CMAJ) features a full-length update on the diagnosis and treatment of OSA in adults. As  Cheryl Laratta form the University of British Columbia and colleagues point out, OSA) is likely underdiagnosed in Canada with lack of appropriate treatment putting many at risk of poor quality of life, comorbidity, motor vehicle crashes and increased health care utilization. Clinical features include daytime sleepiness, unrefreshing sleep or fatigue, frequent nocturnal waking due to choking or gasping, nocturia, morning headaches, poor concentration, irritability and erectile dysfunction. Bed partners may report snoring or witnessed apneas. Atypical symptoms, more frequently reported by women, include insomnia, impaired memory, mood disturbance, reflux and nocturnal enuresis. However, as the authors point out, the correlation of symptoms with disease severity is poor, which is why it is important for physicians to be alert to milder symptoms and screen individuals who present with known risk factors like overweight/obesity, increased neck circumference and nasopharangeal crowding. Importantly, while the presence of these features increases pre-test probability, neither history nor physical examination are enough to rule out OSA. A number of questionnaires (e.g. Berlin Questionnaire, STOP-Bang, etc.) are available to assist in screening patients. As for diagnosis, “The gold standard for diagnosis of OSA is attended polysomnography (level I study), which involves collection of seven or more data channels, including electroencephalogram and electrooculogram for sleep staging, electromyogram, electrocardiogram and respiratory channels.” Less reliably, “Level III sleep studies record a minimum of three channels of data while the patient sleeps at home. Level III studies usually monitor airflow, snoring, respiratory excursion, body position, heart rate and oxygen saturation, but some validated devices use surrogate measurements for these variables, such as tonometry or actigraphy, and the technology is constantly evolving.51 Level III studies do not record sleep; therefore, severity of OSA is estimated using the respiratory event index, which is the number of desaturation events per hour of total recording time.” Treatment options include nightly use of a continuous positive airway pressure (CPAP) device or the use of oral devices (for less severe cases). The latter should be custom fitted by a dentist with extensive experience or additional training in dental sleep medicine. Oddly enough, there is no mention of obesity… Read More »

Urgent Need For Low-Cost In-Home Diagnostics For Obstructive Sleep Apnea

Today’s guest post comes from Christy Turer, MD,  Assistant Professor of Pediatrics, Internal Medicine, and Clinical Sciences at University of Texas Southwestern (UTSW) Medical Center, Dallas, Texas, USA.   This week, I saw a 50 year-old female patient with obesity (BMI 44) who desperately needs screening and treatment for obstructive sleep apnea (OSA). Over the past four years, her heart function (ejection fraction) has declined from >60% to now ~20% with significant pulmonary hypertension, almost certainly related to undiagnosed, untreated OSA based on multiple nightly witnessed apneas. Although she now sleeps with oxygen, this does nothing for her hypopnea-related, sympathetic overdrive-mediated, cardiac dysfunction. Without CPAP treatment, her life expectancy is two years or less. Unfortunately, within the public health system for which I work (county system that offers free or discounted healthcare to poor residents in a metropolitan city, USA), the average wait time for a sleep study is 1-2 years. To be fair, this patient has had a previous attempt at a sleep study in a sleep lab a couple of years ago. At that time, however, the study was inconclusive, because she could not fall asleep in the sleep lab’s unfamiliar environment. It is frustrating not being able to help my patients with suspected sleep apnea, especially, when I know that help could be available. It is high time we had a technological disruption that enables cheap, reliable, in-home OSA assessment for patients. Christy Turer, MD Dallas, TX Dr Turer is a standing member of the US Food and Drug Administration’s Pediatric Advisory Committee, a consultant to the FDA’s Endocrinologic/Metabolic Drugs Advisory Committee, and Past-Chair of the Obesity Society’s Clinical Management of Obesity Section. She has authored numerous scientific articles and lectured widely on primary-care evaluation and management of overweight/obesity and related metabolic comorbidities across the lifespan. Her comments do not reflect the views of UTSW, FDA, or any of her funding sources. 

Weight Loss With Liraglutide Improves Sleep Apnea

The GLP-1 analogue liraglutide (Saxenda), recently launched in North America for the treatment of obesity, has now also been shown to improve symptoms (apnea-hypopnea index – AHI) of obstructive sleep apnea (OSA). This, according to a paper by Blackman and colleagues published in the International Journal of Obesity. This 32-week randomized, double-blind trial was conducted in about 360 non-diabetic participants with obesity who had moderate (AHI 15-29.9 events/h) or severe (AHI ⩾30 events/h) OSA and were unwilling/unable to use continuous positive airway pressure therapy (CPAP). After 32 weeks, the mean reduction in AHI was greater with liraglutide (3.0 mg) than with placebo (-12.2 vs -6.1 events/h). This improvement in sleep apnea was largely explained by the greater mean percentage weight loss compared with placebo (-5.7 vs -1.6%). Additional findings included a greater reductions in HbA1c and systolic blood pressure in the participants treated with liraglutide versus placebo. Liraglutide was generally well tolerated with no unexpected adverse effects. Thus, it appears that in addition to weight loss, treatment with liraglutide 3.0 mg results in clinically meaningful improvements in the severity of obstructive sleep apnea, an important issue that affects both the cardiometabolic risk and quality of life of so many individuals living with obesity. @DrSharma Copenhage, DK Disclaimer: I have received honoraria as a consultant and speaker for Novo Nordisk, the maker of liraglutide

Severity Of Sleep Apnea Is Related To Distance From Sleep Centre

Although sleep apnea is one of the most common and devastating complications of obesity, it remains woefully under-diagnosed and under-treated. One factor accounting for this may well be the lack of timely access to sleep testing. Now, a study by Hirsch Allen and colleagues from the University of British Columbia Hospital Sleep Clinic, published in the Annals of the American Thoracic Society, examined the relationship between severity of sleep apnea and travel times to the clinic in 1275 patients referred for suspected sleep apnea. After controlling for a number of confounders including gender, age, obesity and education, travel time was a significant predictor of OSA severity with each 10 minute increase in travel time associated with an apnea-hypopnea-index increase of 1.4 events per hour. The most likely explanation for these findings is probably related to the fact that the more severe the symptoms, the more likely patients are to travel longer distances to undergo a sleep study. Thus, travel distance may well be a significant barrier for many patients accounting for a large proportion of undiagnosed sleep apnea – at least for milder forms. Given the often vast distances in Canada one can only wonder about just how much sleep apnea goes under diagnosed because of this issue. @DrSharma Edmonton, AB