Is obstructive sleep apnea associated with cortisol levels? A systematic review of the research evidence

a San Diego State University & University of California, San Diego, Joint Doctoral Program in Clinical Psychology, San Diego, UCSD Mail Code 0804, La Jolla, CA, United Statesb Department of Psychiatry, University of California, San Diego, CA, United StatesReceived 8 March 2011. Revised 21 May 2011. Accepted 23 May 2011. Available online 30 July 2011.View full text The pathophysiology of obstructive sleep apnea (OSA) has been associated with dysregulation of the hypothalamic pituitary adrenal (HPA) axis; however a relationship between OSA and altered cortisol levels has not been conclusively established. We conducted a systematic review using the PRISMA Guidelines based on comprehensive database searches for 1) studies of OSA patients compared to controls in whom cortisol was measured and 2) studies of OSA patients treated with continuous positive airway pressure (CPAP) in whom cortisol was measured pre and post treatment. Five electronic databases were searched along with the reference lists of retrieved studies. The primary outcomes were 1) differences in cortisol between OSA and control subjects and 2) differences in cortisol pre-post CPAP treatment. Sampling methodology, sample timing and exclusion criteria were evaluated. Fifteen studies met the inclusion criteria. Heterogeneity of studies precluded statistical pooling. One study identified differences in cortisol between OSA patients and controls. Two studies showed statistically significant differences in cortisol levels pre-post CPAP. The majority of studies were limited by assessment of cortisol at a single time point. The available studies do not provide clear evidence that OSA is associated with alterations in cortisol levels or that treatment with CPAP changes cortisol levels. Methodological concerns such as infrequent sampling, failure to match comparison groups on demographic factors known to impact cortisol levels (age, body mass index; BMI), and inconsistent control of variables known to influence HPA function may have limited the results.

prs.rt("abs_end");Obstructive sleep apnea; Cortisol; Continuous positive airway pressure; Systematic review

Figures and tables from this article:

Fig. 1. PRISMA trial flow used to identify studies for detailed analysis of cortisol in 1) patients with obstructive sleep apnea and healthy controls and 2) patients with obstructive sleep apnea before and after treatment with continuous positive airway pressure. AHI = Apnea hypopnea index; CPAP = Continuous positive airway pressure.

View Within ArticleTable 1. The 7 included studies of cortisol in patients with OSA versus controls.

Na = No information; OSA = Obstructive sleep apnea; BMI = Body mass index; AHI = Apnea hypopnea index; EDS = Excessive daytime sleepiness; w = with; wo = without.

View Within ArticleTable 2. The 8 included studies of cortisol in patients with OSA treated with CPAP.

Na = No information; OSA = Obstructive sleep apnea; BMI = Body mass index; AHI = Apnea hypopnea index; EDS = Excessive daytime sleepiness; SE = Standard error of the mean; w = with; wo = without.

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Secular trends in adult sleep duration: A systematic review

Little evidence exists to support the common assertion that adult sleep duration has declined. We investigated secular trends in sleep duration over the past 40 years through a systematic review.

Systematic search of 5 electronic databases was conducted to identify repeat cross-sectional studies of sleep duration in community-dwelling adults using comparable sampling frames and measures over time. We also attempted to access unpublished or semi-published data sources in the form of government reports, theses and conference proceedings. No studies were excluded based on language or publication date. The search identified 278 potential reports, from which twelve relevant studies were identified for review.

The 12 studies described data from 15 countries from the 1960s until the 2000s. Self-reported average sleep duration of adults had increased in 7 countries: Bulgaria, Poland, Canada, France, Britain, Korea and the Netherlands (range: 0.1–1.7 min per night each year) and had decreased in 6 countries: Japan, Russia, Finland, Germany, Belgium and Austria (range: 0.1–0.6 min per night each year). Inconsistent results were found for the United States and Sweden.

There has not been a consistent decrease in the self-reported sleep duration of adults from the 1960s to 2000s. However, it is unclear whether the proportions of very short and very long sleepers have increased over the same period, which may be of greater relevance for public health.

Table 1. Literature search strategy and number of results for each database.

View Within ArticleTable 2. Summary of included results by country (some studies have multiple results).

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Longitudinal associations between sleep duration and subsequent weight gain: A systematic review

a Doctoral Program in Population Health and Clinical Outcomes Research, Department of Preventive Medicine, HSC Level 3, Stony Brook University, Stony Brook, NY 11794-8338, USAb Department of Preventive Medicine, Graduate Program in Public Health, HSC Level 3, room 071, Stony Brook University, Stony Brook, NY 11794-8338, USAReceived 31 December 2010. Revised 19 May 2011. Accepted 23 May 2011. Available online 23 July 2011.View full text To systematically examine the relationship between sleep duration and subsequent weight gain in observational longitudinal human studies.

Systematic review of twenty longitudinal studies published from 2004–October 31, 2010.

While adult studies (n = 13) reported inconsistent results on the relationship between sleep duration and subsequent weight gain, studies with children (n = 7) more consistently reported a positive relationship between short sleep duration and weight gain.

While shorter sleep duration consistently predicts subsequent weight gain in children, the relationship is not clear in adults. We discuss possible limitations of the current studies: 1) the diminishing association between short sleep duration on weight gain over time after transition to short sleep, 2) lack of inclusion of appropriate confounding, mediating, and moderating variables (i.e., sleep complaints and sedentary behavior), and 3) measurement issues.

prs.rt("abs_end");Sleep; Obesity; Weight gain; Longitudinal studiesBMI, Body mass index; CDC, Centers for Disease Control and Prevention

Figures and tables from this article:

Fig. 1. Illustration of literature search.

View Within ArticleFig. 2. Patel & Hu Model2 with media use added.

View Within ArticleTable 1. Adult studies.

View Within ArticleTable 2. Adult Study Independent Variables.

View Within ArticleTable 3. Children Studies.

View Within ArticleTable 4. Children Study Independent Variables.

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Restless legs syndrome and conditions associated with metabolic dysregulation, sympathoadrenal dysfunction, and cardiovascular disease risk: A systematic review

Kim E. Innesa, b, , , Terry Kit Selfea, b, c, , Parul Agarwala, d, a Department of Community Medicine, West Virginia University School of Medicine, PO Box 9190, Morgantown, WV 26506-9190, USAb Center for the Study of Complementary and Alternative Therapies, University of Virginia Health System, PO Box 800782, McLeod Hall, Charlottesville, VA 22908-0782, USAReceived 1 February 2011. Revised 7 April 2011. Accepted 11 April 2011. Available online 5 July 2011.View full text Restless legs syndrome (RLS) is a distressing sleep and sensorimotor disorder that affects a large percentage of adults in the western industrialized world and is associated with profound reductions in quality of life. However, the etiology of RLS remains incompletely understood. Enhanced understanding regarding both the antecedents and sequelae of RLS could shed new light on the pathogenesis of RLS. Evidence from an emerging body of literature suggests associations between RLS and diabetes, hypertension, obesity, and related conditions linked to sympathetic activation and metabolic dysregulation, raising the possibility that these factors may likewise play a significant role in the development and progression of RLS, and could help explain the recently documented associations between RLS and subsequent cardiovascular disease. However, the relation between RLS and these chronic conditions has received relatively little attention to date, although potential implications for the pathogenesis and treatment of RLS could be considerable. In this paper, we systematically review the recently published literature regarding the association of RLS to cardiovascular disease and related risk factors characterized by sympathoadrenal and metabolic dysregulation, discuss potential underlying mechanisms, and outline some possible directions for future research.

prs.rt("abs_end");Restless legs syndrome; RLS; Ekbom disease; Cardiovascular disease; Hypertension; Diabetes; Impaired glucose tolerance; Obesity; Weight gain; Dyslipidemia; Autonomic dysfunction; HPA axis dysfunction

Figures and tables from this article:

Table 1. Summary table of study characteristics. N = 30 studies (1995-2010).

Abbreviations: CVD = cardiovascular disease; DM = diabetes; DM2 = type 2 diabetes; dx = diagnosis; IGT = impaired glucose tolerance: IRLSSG = international restless legs syndrome study group; Min freq/sev = minimum frequency and/or severity; pts = patients; pts = patients; VA = veterans administration; w/ = with.

View Within ArticleTable 2. Relation of RLS to cardiovascular disease. Summary of study characteristics and findings (N = 15 studies published between 1995 and 2010).

Abbreviations: appt = appointment; ARIC = atherosclerosis risk in communities; BOLD = the burden of obstructive lung diseases study; BP = blood pressure; btwn = between; CAD = Coronary artery disease; CHF = congestive heart failure; CHS = cardiovascular health study; condn = condition; CVD = cardiovascular disease; DM = diabetes mellitus; DM2 = type 2 diabetes; dx = diagnosis; ECA = epidemiologic catchment area; F=female; FBG = fasting blood glucose; FHS = framingham heart study; Freq = frequency; Hgb = hemoglobin; HPFS = health professionals follow-up study; HTN = hypertension; hx = history; ICD = International Classification of Diseases; ICSD = international classification of sleep disorders; IRLS = international RLS study group rating scale; IRLSSG = international restless legs syndrome study group; M = male; MEMO = the memory and morbidity in augsburg elderly study; MI = myocardial infraction; MONICA = monitoring trends and determinants in CVD survey-Augsburg; n’s = numbers; NC-FP-RN = north carolina family practice research network; NHS II = nurses health study II; NSF = national sleep foundation poll; NY cohorts = new york hypertension cohorts; OR = odds ratio (95% Confidence Interval); pt = patient; RLS = restless legs syndrome; SDB = sleep disordered breathing; SHHS = sleep heart health study; SHS = strong heart study; SPAR = the official database covering the total population of Sweden; Sx = symptoms; TG = triglycerides; Tucson cohorts = tucson epidemiologic study of airways obstructive diseases and the health and environment study; tx = treatment; VA = veterans administration; w/ = with; w/o = without.*Calculated from data provided in paper.

View Within ArticleTable 3. Relation of RLS to hypertension: Summary of study characteristics and findings (N = 17 studies published between 1995 and 2010).

Abbreviations: appt = appointment; ARIC = atherosclerosis risk in communities; BOLD = the burden of obstructive lung diseases study; BP = blood pressure; btwn = between; CHF = congestive heart failure; CHS = cardiovascular health study; condn = condition; CVD = cardiovascular disease; DBP = diastolic blood pressure; DM = diabetes mellitus; DM2 = type 2 diabetes; DM1 = type 1 diabetes; dx = diagnosis; ECA = epidemiologic catchment area; F=female; FBG = fasting blood glucose; FHS = framingham heart study; Freq = frequency; Hgb = hemoglobin; HPFS = health professionals follow-up study; HTN = hypertension; hx = history; ICD9CM = international classification of diseases, 9th revision, clinical modification; ICSD = international classification of sleep disorders; IRLS = international RLS study group rating scale; IRLSSG = international restless legs syndrome study group; M = male; MEMO = the memory and morbidity in augsburg elderly study; MI = myocardial infarction; MONICA = monitoring trends and determinants in CVD survey-Augsburg; n’s = numbers; NC-FP-RN = north carolina family practice research network; NHS II = nurses health study II; NSF = national sleep foundation poll; NY cohorts = new york hypertension cohorts; OR = odds ratio (95% Confidence Interval); Pt = patient; RLS = restless legs syndrome; SBP = systolic blood pressure; SDB = Sleep disordered breathing; SHHS = sleep heart health study; SHS = strong heart study; SPAR = the official database covering the total population of Sweden; Sx = symptoms; TG = triglycerides; Tucson cohorts = tucson epidemiologic study of airways obstructive diseases and the health and environment study; tx = treatment; VA = veterans administration; w/ = with; w/in = within; w/o = without.* Calculated from data provided in paper.

View Within ArticleTable 4. Relation of RLS to diabetes and impaired glucose tolerance: Summary of study characteristics and findings (N=26 studies (1995-2010)).

Abbreviations: appt = appointment; ARIC = atherosclerosis risk in communities; BG = blood glucose; BMI = body mass index; BOLD = the burden of obstructive lung diseases study; BP = blood pressure; btwn = between; CHF = congestive heart failure; CHS = cardiovascular health study; condn = condition; CVD = cardiovascular disease; DM = diabetes mellitus; DM1 = type 1 diabetes; DM2 = type 2 diabetes; dx = diagnosis; ECA = epidemiologic catchment area; F=female; FBG = fasting blood glucose; FHS = framingham heart study; Freq = frequency; Hgb = hemoglobin; HOMA = homeostasis model assessment; HPFS = health professionals follow-up study; HTN = hypertension; hx = history; ICD9CM = international classification of diseases, 9th revision, clinical modification; IGT = impaired glucose tolerance; ICSD = international classification of sleep disorders; IGR = impaired glucose regulation; IGT = impaired glucose tolerance; IRLS = international RLS study group rating scale; IRLSSG = international restless legs syndrome study group; M = male; MEMO = the memory and morbidity in augsburg elderly study; MONICA = monitoring trends and determinants in CVD survey-Augsburg; NC-FP-RN = north carolina family practice research network; NHS II = nurses health study II; NSF = national sleep foundation poll; NY cohorts = new york hypertension cohorts; OGTT = oral glucose tolerance test; OR = odds ratio (95% Confidence Interval); pts = patients; RLS = restless legs syndrome; SDB = sleep disordered breathing; SHHS = sleep heart health study; SHS = Strong heart study; SPAR = the official database covering the total population of Sweden; Sx = symptoms; TG = triglycerides; Tucson cohorts = tucson epidemiologic study of airways obstructive diseases and the health and environment study; tx = treatment; VA = veterans administration; w/ = with; w/in = within; w/o = without.*Calculated from data provided in table.

View Within ArticleTable 5. Relation of RLS to obesity, weight gain, and dyslipidemia: Summary of study characteristics and findings (N=18 studies with data on the association of RLS to obesity/weight gain, 7 studies with data on the association of RLS to lipid profiles).

Abbreviations: appt = appointment; ARIC = atherosclerosis risk in communities; BMI = body mass index; BOLD = the burden of obstructive lung diseases study; BP = blood pressure; btwn = between; CHF = congestive heart failure; CHS = cardiovascular health study; condn = condition; CVD = cardiovascular disease; DM = diabetes mellitus; DM1 = type 1 diabetes; DM2 = type 2 diabetes; dx = diagnosis; ECA = epidemiologic catchment area; F=female; FBG = fasting blood glucose; FHS = framingham heart study; Freq = frequency; Hgb = hemoglobin; HPFS = health professionals follow-up study; HTN = hypertension; hx = history; ICSD = international classification of sleep disorders; IRLS = intl RLS study group rating scale; IRLSSG = international restless legs syndrome study group; M = male; MEMO = the memory and morbidity in augsburg elderly study; MI = myocardial infarction; MONICA = Monitoring trends and determinants in CVD survey-Augsburg; NC-FP-RN = north carolina family practice research network; NHS II = nurses health study II; NSF = national sleep foundation poll; NY cohorts = new york hypertension cohorts; OGTT = oral glucose tolerance test; OR = odds ratio (95% confidence interval); RLS = restless legs syndrome; SDB = sleep disordered breathing; SHHS = sleep heart health study; SHS = strong heart study; SPAR = the official database covering the total population of Sweden; Sx = symptoms; TG = triglycerides; Tucson cohorts = tucson epidemiologic study of airways obstructive diseases and the health and environment study; tx = treatment; VA = veterans administration; w/ = with; w/o = without.*Calculated from data provided in paper.

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