Short sleep duration, sleep disturbances, and unsynchronized circadian sleep rhythms are associated with metabolic disorders, markedly, obesity and type 2 diabetes, prompting suggestions that sleep needs to be addressed "in a much more structured way than it is currently done in clinical routine," say the authors of a new review.
Distinct pathophysiological mechanisms have been found to underlie the effect of sleep loss on metabolic health, says the review, published online March 25 in Lancet Diabetes & Endocrinology by endocrinologists in Germany, Switzerland, and the United Kingdom.
Coauthor Sebastian Schmid, MD, from the University of Lübeck, Germany, and the Wellcome Trust–Medical Research Council Institute of Metabolic Science, University of Cambridge, United Kingdom, said the work confirms there is a clear and clinically relevant link between short and disturbed sleep and metabolic disease.
However, he emphasized the importance of identifying at-risk patients before intervening. He also pointed out that screening tools — for example, the Pittsburgh Sleep Quality Index — are available, perform well, and are easy to use to evaluate the risk for sleep disturbance and short sleep duration in individual patients.
"Considering the high prevalence of sleep disturbances and especially their increasing incidence, we should focus more on poor sleep as a potential metabolic risk factor in our patients," he told Medscape Medical News. "I think it is important to raise healthcare providers' awareness to the metabolic importance of sleep in our patients."
Another coauthor, Bernd Schultes, MD, from the eSwiss Medical and Surgical Center, St. Gallen, Switzerland, agrees. While genetic predisposition, as well as physical activity and diet, play important roles in metabolic disorders, "it's important to start by asking a patient about their sleep patterns. Furthermore, technical devices, which are increasingly available for lifestyle monitoring, will provide more objective data," he observed.
Lifestyle Factors Predispose to Metabolic Disorders
In the review, the authors describe large epidemiological and observational studies originating from the late 1990s that pointed to the poor-sleep–metabolic-disorders link and note that these data were supplemented by an increasing understanding of the mechanisms responsible for the association.
"Experimental studies indicate that sleep loss leads to insulin resistance and an increased drive to consume energy-dense food," they observe. And circadian misalignment superimposing sleep restriction "also amplifies the detrimental effects of sleep loss on metabolic health."
Dr. Schmid pointed out that while the link between sleep and metabolism is inevitably a multifactorial one, there are relevant mechanisms at play that drive the association, including hormonal pathways — for example, the endogenous stress axis (hypothalamus-pituitary-adrenal axis known as the corticotropic axis) as well as the autonomous nervous system.
And apart from "classical biochemical" pathways, "behavioral changes, including physical activity and food choice, link the amount and quality of sleep to energy homeostasis," he observed.
24-Hour Lifestyle Exacerbates the Problem
Of particular note, the review authors draw attention to 24-hour lifestyle and ongoing trends for use of technical devices for gaming, online shopping, social networking, or watching television as contributing factors for sleep disturbance.
"From a public-health perspective it will be most important to reduce voluntary sleep restriction caused by computer gaming, electronic social-media use, etc, in particular in teenagers," advised Dr. Schultes.
So more than ever, sleep loss is a "promising target for the prevention and probably the treatment of the metabolic syndrome and its components," say he and his colleagues, although Dr. Schultes acknowledged that it is currently "unclear whether an improvement of sleep can improve diabetes that is already established."
And "for people who cannot avoid periods of sleep restriction and circadian misalignment — for example, shift workers — interventions that increase sleep quality appear promising," he notes.
The review illustrates this with the inclusion of 2 large cohort studies that have shown a clear association between shift work and adverse metabolic traits.
In one study of 1811 employees of an airline company, the prevalence of metabolic syndrome was 2.13 times higher in shift workers than in regular daytime workers. In addition, a data set from 26,463 retired Chinese workers showed that previous shift work was associated with an increased risk for development of hypertension (odds ratio [OR], 1.05), type 2 diabetes (OR, 1.10) and poor self-reported sleep quality (OR, 1.18).
Sleep education programs and cognitive behavioral therapies focusing on improving sleep represent promising approaches to induce changes, the authors add.
Intervene to Improve Sleep, Address Metabolic Disease
Dr. Schmid reinforced the need to identify at-risk patients as being central to preventing metabolic disease and/or providing excellent medical care.
Among his suggestions are that quality of sleep can be improved by basal lifestyle interventions, among them stress reduction, ensuring a dark and quiet sleep environment, regulation of bedroom temperature, regular sleep/wake cycle, light dinner, no alcohol at night, and no use of electronic games, mobile phones, or computers just before sleeping.
But in some cases, specific interventions might be necessary, he observed.
"If there is a certain sleep disturbance, specific therapies — eg, continuous positive airway pressure (CPAP) therapy for patients with obstructive sleep apnea syndrome — clearly has an impact on metabolic health and quality of life," he concluded.
Lancet Diabetes Endocrinol 2014. Published online March 25, 2014. Summary
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Cite this: Target Sleep Loss to Prevent and Treat Diabetes and Obesity? - Medscape - Mar 25, 2014.