Literature Updates from September 2013

Self-Reported Sleep Disturbance is Associated With Lower CD4 Count and 24-Hour Urinary Dopamine Levels in Minority Women Living With HIV

A study 139 low income women with HIV found that after controlling for HIV viral load, length of time with HIV, HAART adherence, perceived stress and depression, greater sleep disturbance, by self-report, was associated with lower CD4 count and lower levels of dopamine. Poorer overall sleep quality, measured by PSQI, was marginally associated with CD4 count.

Disturbed Sleep and Inflammatory Cytokines in Depressed and Nondepressed Pregnant Women: An Exploratory Analysis of Pregnancy Outcomes

Self-reported sleep and plasma cytokines were obtained in a cohort of depressed and non-depressed pregnant women at 20 and 30 weeks gestation. Among depressed women, short sleep duration was associated with higher IL-8, while poor sleep continuity was associated with higher IL-6. Higher IFN-gamma was associated with increase risk of pre-term birth in depressed women.

Acute Sleep Restriction Reduces Insulin Sensitivity in Adolescent Boys

In a randomized cross-over design, 21 healthy normal weight males underwent 3 consecutive nights of sleep restriction (4 hr/night) and long sleep (9 hr/night). Pre– and post-prandial glucose, insulin and other metabolic markers were obtained. Fasting insulin, fasting C-peptide and post-prandial C-peptide were higher in sleep restriction condition than long sleep. HOMA-IR was also higher under sleep restriction.

Habitual Shortened Sleep and Insulin Resistance: An Independent Relationship in Obese Individuals

Non-diabetic, overweight/obese participants who were insulin-resistant or insulin-sensitive underwent an oral glucose tolerance test.  Individuals reporting short habitual sleep duration (<7 hours/night) were more likely to be insulin-resistant than insulin-sensitive.

Sleep Fragmentation Promotes NADPH Oxidase 2-Mediated Adipose Tissue Inflammation Leading to Insulin Resistance in Mice

These studies imply that sleep fragmentation, a frequent occurrence in many disorders and more specifically in sleep apnea, is a potent inducer of insulin resistance via activation of oxidative stress and inflammatory pathways.

Intermittent Hypoxia and Hypercapnia Induce Pulmonary Artery Atherosclerosis and Ventricular Dysfunction in Low Density Lipoprotein Receptor Deficient Mice

This study “raises the possibility that patients with obstructive sleep apnea may be susceptible to atherosclerotic disease in the pulmonary vasculature”.

Prolonged Sleep Fragmentation of Mice Exacerbates Febrile Responses to Lipopolysaccharide

This study shows that prolonged sleep disruption of mice exacerbates febrile responses to lipopolysaccharide. This device provides a method to determine mechanisms by which chronic insufficient sleep contributes to the etiology of many pathologies, particularly those with an inflammatory component.

How Do We Know When Patients Sleep Properly or Why They Do Not?

In a commentary published in the journal Critical Care, Folke Sjober and Eva Svanborg point on the importance of Dr. Elliot’s article which we reviewed in the May 2013 newsletter entitled “Characterization of sleep in intensive care using 24-hour polysomnography: an observational study”. Specifically, the authors point out the importance of studying sleep in the ICU with regards to understanding oxidative stress, immune function and subjective health. They applaud the authors for using polysomnography in such a large sample of ICU patients. However, Solberg and Svanborg admit we are only at the “tip of the iceberg” with regards to our understanding of the importance of sleep in the ICU and how to best study it.

Seasonal Variation in a Clinical Referral Pediatric Cohort at Risk for Obstructive Sleep Apnea

Seasonal changes are present in children with clinically symptomatic OSA and differ among younger and older children, with global trends toward improved AHI during summer, especially in younger children.