Disrupted sleep increases the risk of cardiovascular disease by promoting inflammation

June 4, 2020

Science Daily/PLOS

Sleep disruption has been shown to be associated with an increased risk of atherosclerosis, but the mechanism has been unclear. A new study in the open-access journal PLOS Biology by Raphael Vallat, Vyoma Shah, and Matthew Walker of the University of California at Berkeley and colleagues reveals that fragmented sleep exacerbates atherosclerosis and may raise the risk of stroke via an effect on inflammatory pathways. These results provide a mechanism to explain the long-standing observation that poor sleep increases the risk of heart disease and stroke, and suggest simple and direct ways to reduce such risk.

To test whether the effect may be due in part to increased inflammatory signaling, the authors measured sleep disruption through both sleep lab-based polysomnography and a simple movement detector worn on the wrist over multiple nights (actigraphy). They used standard blood cell counts to measure levels of neutrophils and monocytes, two types of white blood cells responsible for driving inflammatory pathways.

They found that sleep fragmentation, as measured by actigraphy, predicted both higher neutrophil (but not monocyte) counts and higher coronary artery calcium, a measure of atherosclerosis pathology. Using a statistical method known as mediation analysis, they showed that the influence of sleep fragmentation on coronary artery calcium was mediated through the increase in neutrophils; in other words, poor sleep led to an increase in neutrophils, which in turn led to an increase in atherosclerosis. The influence of sleep disruption on neutrophils and atherosclerosis remained significant after accounting for multiple known contributors to artery disease, including age, sex, ethnicity, body mass index, smoking, blood pressure, and other factors.

A similar association was found for sleep disruption as measured by polysomnography, although it was not as robust, remaining significant after correcting for some but not all contributors, a difference the authors suggest may be due to the shorter duration of polysomnography (a single night) versus actigraphy (one week). No association was found for subjectively reported poor sleep, in which subjects were asked to recall the quality of their sleep, a finding which suggests that asking patients about the sleep may not be a useful tool for assessing their sleep-related risk of heart disease.

"Improving sleep may offer a novel way to reduce inflammation and thus reduce the risk of atherosclerosis," Walker said. "These findings may help inform public health guidelines that seek to increase the continuity of sleep as a way to improve health and decrease the burden of heart disease on society."

https://www.sciencedaily.com/releases/2020/06/200604152108.htm

Poor infant sleep may predict problematic toddler behavior

Study finds frequent night wakings, broken sleep patterns are linked to trouble later on

October 8, 2015

Science Daily/American Friends of Tel Aviv University

A recent study finds a definite link between poor infant sleep and compromised attention and behavior at the toddler stage.

Temper tantrums and misbehavior, restlessness and inattention are the trappings of the typical toddler. But they may also be signs of developmental delays or disorders. Are infant sleep irregularities red flags for later ?

A study recently published in Developmental Neuropsychology finds a definite link between poor infant sleep and compromised attention and behavior at the toddler stage. The research discovered that one-year-olds who experienced fragmented sleep were more likely to have difficulties concentrating and to exhibit behavioral problems at three and four years of age.

The research was led by Prof. Avi Sadeh of Tel Aviv University's School of Psychological Sciences and conducted by a team that included his TAU colleagues Yael Guri and Prof. Yair Bar-Haim; Dr. Gali De Marcas of the Gordon College of Education in Haifa; and Prof. Andrea Berger and Dr. Liat Tikotzky of Ben Gurion University of the Negev.

A predictor of future problems

"Many parents feel that, after a night without enough sleep, their infants are not at their 'best.' But the real concern is whether infant sleep problems -- i.e. fragmented sleep, frequent night wakings -- indicate any future developmental problems," said Prof. Sadeh. "The fact that poor infant sleep predicts later attention and behavior irregularities has never been demonstrated before using objective measures."

The team assessed the sleep patterns of infants at TAU's Laboratory for Children's Sleep Disorders, where Prof. Sadeh is director. The initial study included 87 one-year-olds and their parents. They revisited the lab when the infants were three to four years old. According to the study, "Night-wakings of self-soothing infants go unnoticed by their parents. Therefore, objective infant sleep measures are required when assessing the role of sleep consolidation or sleep fragmentation and its potential impact on the developing child."

To accomplish this, the researchers used wristwatch-like devices to objectively determine sleep patterns at the age of one, and in the follow-up visits they used a computerized attention test, the Spatial-Stroop task, to assess attentional executive control. They also referred to parental reports to determine signs of behavioral problems.

The results revealed significant predictive and concomitant correlations between infant sleep and toddler attention regulation and behavior problems. The study points to significant ties between sleep quality markers (sleep percentage and number of night wakings) at one year of age and attention and behavior regulation markers two to three years later.

Is it genetic?

"We don't know what the underlying causes are for the lower sleep quality and later behavior regulation problems in these children," said Prof. Sadeh. "There may be genetic or environmental causes adversely affecting both the children's sleep and their development in other domains. Our findings, however, support the importance of early diagnosis and treatment of sleep problems in infants and young children. Early interventions for infant sleep problems, very effective in improving sleep quality, could potentially improve later attention and behavior regulation."

The researchers are currently exploring the underlying characteristics of children who are considered "good sleepers" at the age of nine to 18 months.

http://www.sciencedaily.com/releases/2015/10/151008142505.htm