Less Sleep Ups Risk of Diabetes and Obesity
A study by researchers at Brigham and Women’s Hospital (BWH) reinforces the finding that too little sleep or sleep patterns that are inconsistent with our body’s “internal biological clock” may lead to increased risk of diabetes and obesity. This finding has been seen in short-term lab studies and when observing human subjects via epidemiological studies. However, unlike epidemiological studies, this new study provides support by examining humans in a controlled lab environment over a prolonged period, and altering the timing of sleep, mimicking shift work or recurrent jet lag.
Researchers hosted 21 healthy participants in a completely controlled environment for nearly 6 weeks.
The researchers controlled how many hours of sleep participants got, as well as when they slept, and other factors such as activities and diet. Participants started with getting optimal sleep (approximately 10 hours per night). This was followed by 3 weeks of 5.6 hours of sleep per 24-hour period and with sleep occurring at all times of day and night, thereby simulating the schedule of rotating shift workers. Thus, during this period, there were many days when participants were trying to sleep at unusual times within their internal circadian cycle. The study closed with the participants having 9 nights of recovery sleep at the usual time.
The researchers saw that prolonged sleep restriction with simultaneous circadian disruption decreased the participants’ resting metabolic rate. Moreover, during this period, glucose concentrations in the blood increased after meals, because of poor insulin secretion by the pancreas.
According to the researchers, a decreased resting metabolic rate could translate into a yearly weight gain of over 10 pounds if diet and activity are unchanged. Increased glucose concentration and poor insulin secretion could lead to an increased risk for diabetes.
“We think these results support the findings from studies showing that, in people with a pre-diabetic condition, shift workers who stay awake at night are much more likely to progress to full-on diabetes than day workers,” said Orfeu M. Buxton, PhD, BWH neuroscientist and lead study author. “Since night workers often have a hard time sleeping during the day, they can face both circadian disruption working at night and insufficient sleep during the day. The evidence is clear that getting enough sleep is important for health, and that sleep should be at night for best effect.”
The study was electronically published in Science Translational Medicine.
Sleep Apnea Spikes Death Risk
Sleep apnea is associated with an increased risk of death, according to new results from the Wisconsin Sleep Cohort, an 18-year observational study supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.
Researchers found that adults (ages 30 to 60) with sleep-disordered breathing at the start of the study were two to three times more likely to die from any cause compared to those who did not have sleep-disordered breathing. The risk of death was linked to the severity of sleep-disordered breathing and was not attributable to age, gender, body mass index (an indicator of overweight or obesity), or cardiovascular health status.
The 1,522 study participants included a mix of generally healthy men and women who were between the ages of 30 and 60 years when the research began. Each person was given an overnight sleep test at the beginning of the study, and then each was followed for an average of 13.8 years.
This study is the most comprehensive assessment of mortality risks associated with sleep apnea to date. The researchers note that these findings suggest that treatment of severe sleep-disordered breathing may help protect sufferers from an increased risk of death.
“Sleep-Disordered Breathing and Mortality: Eighteen-Year Follow-Up of the Wisconsin Sleep Cohort,” was published in the journal Sleep.
Women with Sleep Apnea Have a Higher Degree of Brain Damage than Men
Women suffering from sleep apnea have a higher degree of brain damage than men with the disorder, according to a study conducted by researchers at the UCLA School of Nursing.
The multi-year study, titled “Sex Differences in White Matter Alterations Accompanying Obstructive Sleep Apnea,” looks at patients diagnosed with obstructive sleep apnea. Researchers compared the nerve fibers in these patients’ brains to fibers of individuals without sleep problems and focused on unearthing the difference in brain damage between men and women with sleep apnea.
“This study revealed that, in fact, women are more affected by sleep apnea than are men and that women with obstructive sleep apnea have more severe brain damage than men suffering from a similar condition,” said chief investigator Paul Macey, assistant professor and associate dean of information technology and innovations at the UCLA School of Nursing.
In particular, the study found that women were impacted in the cingulum bundle and the anterior cingulate cortex, areas in the front of the brain involved in decision-making and mood regulation. The women with sleep apnea also showed higher levels of depression and anxiety symptoms.
“What we don’t yet know,” said Macey, “is, did sleep apnea cause the brain damage, did the brain damage lead to the sleep disorders, or did the common comorbidities, such as depression, dementia, or cardiovascular issues, cause the brain damage, which in turn leads to sleep apnea.”
The findings are reported in the December issue of SLEEP
Sleep Apnea Linked to Silent Strokes
People with severe sleep apnea may have an increased risk of silent strokes and small lesions in the brain, according to a small study presented at the American Stroke Association’s International Stroke Conference 2012.
“We found a surprisingly high frequency of sleep apnea in patients with stroke that underlines its clinical relevance as a stroke risk factor,” said Jessica Kepplinger, MD, the study’s lead researcher and stroke fellow in Dresden University Stroke Center’s Department of Neurology at the University of Technology in Dresden, Germany.
“Sleep apnea is widely unrecognized and still neglected. Patients who had severe sleep apnea were more likely to have silent strokes, and the severity of sleep apnea increased the risk of being disabled at hospital discharge.”
The researchers found:
- 91% (51 of 56) of the patients who had a stroke had sleep apnea and were more likely to have silent strokes and white matter lesions that increased risk of disability at hospital discharge.
- Having more than five sleep apnea episodes per night was associated with silent strokes.
- More than one-third of patients with white matter lesions had severe sleep apnea and more than 50% of silent stroke patients had sleep apnea.
- Even though men were more likely to have silent infarcts, correlations between sleep apnea and silent infarcts remained the same after adjustment for such gender differences.
New Information Connects Obstructive Sleep Apnea with Depression
Snorting, gasping, or stopping breathing while asleep was associated with nearly all depression symptoms, including feeling hopeless and feeling like a failure, according to results from what authors say is the first nationally representative sampling to examine this relationship. They note that additional research may be needed to determine whether regular screening for these conditions by mental health professionals and sleep specialists should be recommended.
The data come from survey results using the PHQ-9, the nine item depression scale of the Patient Health Questionnaire, in a national sample of 9,714 American adults. In men, sleep apnea was associated with probable major depression, but snoring was not associated with depression symptoms in men or women. Snorting/stopping breathing 5 nights a week or more was strongly associated with probable major depression in both genders, as compared to those who never experienced these issues.
The likelihood of depression increased with the reported frequency of snorting and/or instances when breathing stopped in the study, according to lead author Anne G. Wheaton, PhD. She suggested screening for both disorders could help address the high prevalence and under-diagnosis of sleep apnea and depression, especially if sleepiness is a chief complaint.