Deirdre Budd’s Blog

According to a study from the Wisconsin Sleep Cohort, which was presented at SLEEP 2010: Associated Professional Sleep Societies 24th Annual Meeting, Chronic Insomnia is associated with an approximately 2-fold increased risk for all-cause mortality.

Researchers, led by Laurel Finn, MS, a biostatistician at the University of Wisconsin School of Medicine in Madison, determined all-cause mortality by examining a social security death index in June 2009. They used Cox proportional hazards regression to estimate mortality hazard ratios. These were adjusted for body mass index, age, sex, and chronic conditions that patients said their physicians had diagnosed, including emphysema, chronic bronchitis, angina, coronary heart disease, heart attack, stroke, hypertension, and diabetes.

The study looked at the association between chronic insomnia and mortality rate, independent of health conditions. Subjects were drawn from participants in the Wisconsin Sleep Cohort Study who completed 3 mailed surveys in 1989, 1994, and 2000. Surveys asked about insomnia-related topics such as difficulty falling asleep, difficulty getting back to sleep, repeated awakening, and early arousal. Respondents marked symptoms as frequent (≥5 times per month) or not frequent (<5 times per month). They were considered to have chronic insomnia if they reported symptoms on at least 2 surveys.

Ms. Finn, who presented the survey said, “Sleep duration has been linked to (increased) mortality, and a lot of insomniacs have short sleep duration. We wondered if this could be one of the mechanisms by which short sleep duration leads to mortality. We have been studying these people for 20 years, and have a lot of data on them.” The ongoing study has a population-based cohort, which allowed researchers to examine the natural history of participants. 

The study is preliminary, and the next step is to examine how insomnia affects health outcomes in comorbid conditions. “People with insomnia are fatigued. [Higher mortality could result] if they have a chronic condition and they don’t follow-up on treatment [because of the fatigue],” The findings of this study should prompt doctors to take insomnia more seriously and look for the root causes whether they be behavioural, or if there is real difficulty falling asleep or maintaining sleep. There are some new pharmacotherapies that work on specific kinds of insomnia. However, the root causes need to be addressed.

It can be difficult to determine whether the insomnia itself increases mortality or if the underlying conditions are causing the insomnia. This study has offered the clearest, most structured look at this topic so far.

The body’s primary circadian clock resides deep in the brain, but local biological clocks also are found in tissues throughout the body, including the pancreas, lungs, liver, heart and skeletal muscles. These clocks operate on a 24-hour, circadian (Latin for “about a day”) cycle that governs functions such as sleeping and waking, rest and activity, fluid balance, body temperature, cardiac output, oxygen consumption, metabolism and endocrine gland secretion.

As part of this system, our fundamental body systems such as sleep wake cycles and when we feel hunger are also regulated. Recent research, led by Bass and Biliana Marcheva,  first author of the paper, involving key collaborators Louis H. Philipson of the University of Chicago, Joseph S. Takahashi of the University of Texas Southwestern Medical Center and Seth D. Crosby of the Washington University School of Medicine. Looked at the development of diabetes and the links between insulin production and the circadian rhythm.

In their study, the researchers knocked out the clock genes in islet beta-cells in mice, and found the animals developed impaired glucose tolerance, and abnormally low levels of insulin. They went on to develop diabetes. The clock of the beta-cell coordinates glucose management, and the loss of the clock inhibited the cells from secreting insulin.

These findings will help in working out the causes of glucose abnormalities, but there is still a lot to learn. The researchers showed that insulin-secreting islet cells in the pancreas, called beta-cells, have their own dedicated clock. The clock governs the rhythmic behavior of proteins and genes involved in insulin secretion, with oscillations over a 24-hour cycle. “This is the first evidence of how the circadian clock may affect the development of diabetes,” said Joe Bass, M.D. “The biological programs in animals for harvesting energy, are under control of this clock.”

 “The variation we see in insulin secretion in humans, and susceptibility to diabetes, is likely related to this clock mechanism,” said Bass, an endocrinologist trained in molecular genetics. “There is an association in the changes of the cycling of the clock within the pancreas itself and disease. The question is, can we can modulate this?”

Diabetes is the seventh most common cause of death in America and costs every country a huge amount in health care and disablilty. Anything which can reduce the impact or the number of people who suffer from the effects of diabetes should be welcomed.

Doctors from the University of Auckland, New Zealand, recently did a randomised control trial of positioning treatments for infants with plagiocephaly and brachycepahly. In this study head shape was measured digitally and neck function was assessed. Children were followed up at 3,6 nad 12 months. One group were treated using positional strategies and one with positioning strategies and a SafeT sleep.  The results of this study showed  that there was no difference in head shape outcomes for the two treatment groups after 12 months of follow up, with 42% of infants having head shapes in the normal range by that time. Eighty percent of children showed good improvement. Those that had poor improvement were more likely to have both plagiocephaly and brachycephaly and to have presented later to clinic.

 Most infants improved over the 12-month study period, although the use of a sleep positioning wrap did not increase the rate of improvement.

For some years now we have known that an off-kilter body clock can throw off our sleep-wake cycle, eating habits, body temperature and hormones—and mounting evidence suggests a malfunctioning clock may also underlie the mood cycles in bipolar disorder.

In a Indiana University, a new study led by psychiatrist Alexander Niculescu, researchers found that children with bipolar disorder were likely to have a mutated gene, which codes for a particular  protein, crucial to circadian clock function. The team’s previous work identified alterations to this gene, and other clock genes, in animal models of bipolar disorder.  In the new study, the scientists compared the genomes of 152 bipolar children, with those of 140 typical children. (Children were studied because their moods cycle more rapidly than the moods of bipolar adults, and a quicker cycle suggests a stronger connection to the circadian clock.) The team found that the bipolar children were more likely to have one of four alterations to this particular gene. The investigators suspect that these mutations prevent the body from producing the right amount and type of protein to support normal circadian rhythm.

Previous studies have demonstrated that altering the sleep wake cycle has a profound effect on mood. Regulating sleep wake can improve extreme  mood cycles but the experts were not sure why, until animal studies showed  a connection to  the genes that control the setting of circadian rhythms.

 Jodi Mindell,Phd, Professor of Psychology at Saint Josephs University in Philadelphia,  as lead author, presented a study at the Annual meeting of the associated Professional Sleep Studies, which looked again at bed sharing.  Previous studies have always indicated that bed sharing is associated with increased sleep problems, primarily more night waking in young children. However it is now apparent that Parental presence at bedtime appears to have a greater negative impact on infant sleep, than actual co-sleeping.

Results indicate that children who slept in a separate room obtained more sleep, woke less at night, had less difficulty at bedtime, fell asleep faster, and were perceived as having fewer sleep problems. These clinically significant differences were mostly observed in children who lived in primarily Caucasian countries, and not in countries that were predominantly Asian.

“However, it is likely that it is not the bed sharing or room sharing per se, that leads to increased sleep issues,” says Mindell. “Rather, most young children who sleep in a separate room fall asleep independently of their parents. These children are able to return to sleep on their own when they naturally awaken during the night, and thus have fewer sleep problems. Children who sleep in the same room as their parents usually have a parent helping them to fall asleep at bedtime, and will need that help again throughout the night.”

Recent research by Alissa Ferry, Susan Hespos and Sandra Waxman, in the psychology department in the Weinberg College of Arts and Sciences, will appear in the March/April edition of the journal Child Development.. Infants who heard words, provided evidence of categorization, while infants who heard tone sequences did not.

The results, say the authors, were striking. The researchers found that although infants who heard in the word and tone groups saw exactly the same pictures for exactly the same amount of time, those who heard words formed the category fish; those who heard tones did not.

Participants included 46 healthy, full-term infants, from 2 to 4 months of age. Half of the infants within each age bracket were randomly assigned to the word group. All infants in the language group were from families where English was the predominant language spoken in the home. The remaining infants were in the tone group.

Three-month-old infants were shown a series of pictures of fish that were paired with words or beeps. Infants in the word group were told, for example, “Look at the toma!” ?– a made-up word for fish, as they viewed each picture. Other infants heard a series of beeps carefully matched to the labelling phrases for tone and duration. Then infants were shown a picture of a new fish and a dinosaur side-by-side as the researchers measured how long they looked at each picture. If the infants formed the category, they would look longer at one picture than the other.

“We suspect that human speech, and perhaps especially infant-directed speech, engenders in young infants a kind of attention to the surrounding objects that promotes categorization,” said Waxman, a co-author and professor of psychology. “We proposed that over time, this general intentional effect would become more refined, as infants begin to cull individual words from fluent speech, to distinguish among individual words and kinds of words, and to map those words to meaning.”

In 2008 Tucker,Dahgreen, Akerstedt and Waterhouse compared the different types of free time activity on the indices of sleep recovery and well being.  Twelve individuals spent four consecutive evenings after work in three different conditions. Pursuing quiet leisure activities at home, taking part in active leisure pursuits and doing additional work.

Unsurprisingly less satisfaction, rest and recuperation were reported in those doing additional work. Despite there being few other differences between conditions the group who reported better rest, recuperation and sleep were those who were satisfied with their evening activities.

Evening activities which required less mental effort were also associated with better sleep less fatigue the following day and improved recuperation. It was concluded that the nature of the activity may be less important than the individual preference and the cumulative demands of both day and evening activities.

In another study looking at the effect of blue enriched white light during daytime working hours in an office setting. Daytime sleepiness was reduced, and improvement was noted in subjective alertness, performance and evening fatigue. This study involved 104 white collar workers on two office floors and was conducted and reported by Viola, James, Schlangen and Dijk in the Scandinavian Journal of Work and Environmental Health 2008.