Correlates of serum C-reactive protein (CRP)--no association with sleep duration or sleep disordered breathing

Associations between sickness behavior, but not inflammatory cytokines, and psychiatric comorbidity in chronic pain

OBJECTIVES

Approximately one in five adults experiences chronic pain, often in co-occurrence with depression, insomnia, anxiety, and lower self-rated health. Elevated levels of cytokines, e.g. tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 8 (IL-8), and interleukin 10 (IL-10), have been identified in patients with chronic pain. Depression, insufficient sleep, poor self-rated health, and pain intensity have also been associated with inflammatory biomarkers. This study aimed to investigate the interrelationships between inflammatory biomarkers and depression, insomnia, anxiety, self-rated health, sickness behavior, and pain intensity in patients with chronic pain.

METHODS

Self-report questionnaires and blood samples analyzed for plasma levels of inflammatory biomarkers were collected from 80 adult patients with chronic pain. Associations between inflammatory biomarkers (TNF-α, IL-6, IL-8, IL-10, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR)) and depression, insomnia, anxiety, self-rated health, sickness behavior, and pain intensity, were analyzed using bivariate Spearman rank correlation coefficients and regression analyses.

RESULTS

Participants were mainly women (72.5 %), with a mean age of 50.8 years, and a reported mean pain duration of 16.7 years. There were significant correlations between insomnia and CRP (rs =.26, p <.05); sex and ESR (rs =.29, p <.05); age and IL-6 (rs =.29, p <.05) and IL-8 (rs =.30, p <.05); BMI and IL-6 (rs =.50, p <.001), CRP (rs =.63, p <.001) and ESR (rs =.42, p <.001). Ratings of depression were positively and significantly related to ratings of sickness behavior and anxiety (β =.32 and β =.40, respectively), explaining 49 % of the total variance in depression ratings. Insomnia was positively and significantly related to sickness behavior (β =.37) explaining 31 % of the total variance in insomnia ratings. Inflammatory biomarkers, however, did not contribute significantly to the models.

CONCLUSIONS

Participants reported high levels of symptoms, yet the associations between these ratings and the inflammatory biomarkers were either absent or weak. Also, despite high levels of self-reported sickness behavior, overall the inflammatory status remained within the normal range. Ratings of sickness behavior contributed more than inflammatory markers in explaining ratings of depression and insomnia. The present results point to the complexity of chronic pain, and the challenges of identifying biomarkers that explain symptomatology.

Elevated oxidative stress biomarkers in adults with segmented sleep patterns

STUDY OBJECTIVES

We investigated the association between different sleep patterns and inflammatory and oxidative stress biomarkers in adults.

METHODS

A total of 321 consented adults who fulfilled the inclusion criteria were recruited in this cross-sectional study. The inclusion criteria were mainly based on apparently healthy adults aged 18-59 years. To identify sleep patterns, participants were requested to wear the actigraph for 1 week for 24 hours a day. Fasting blood was collected from each participant at day 8. The blood serum was analyzed for inflammatory and oxidative stress biomarkers. Sleep patterns were defined as monophasic (1 episode of night sleep) biphasic (2 episodes of sleep; night and aternoon siesta), and polyphasic sleep pattern (3 or more sleep episodes).

RESULTS

There was no correlation between night sleep duration, total sleep in 24 hours, and napping among inflammatory and oxidative stress biomarkers: high-sensitivity C-reactive protein, malondialdehyde, total glutathione, and basal oxidizability status. Actigraphy reports showed 3 sleep patterns in this cohort, monophasic (24.3%), biphasic-napping (45.2%) and polyphasic (30.5%). Individuals with segmented sleep patterns were significantly associated with oxidative stress biomarkers. A polyphasic sleep pattern was significantly associated with higher basal oxidizability status (P = .023), whereas a biphasic sleep pattern showed higher malondialdehyde (P = .036) as compared to a monophasic sleep pattern. Total glutathione was significantly higher in monophasic sleepers (P = .046). There was no difference in serum high-sensitivity C-reactive protein among all sleep patterns.

CONCLUSIONS

Segmented sleep in polyphasic and biphasic sleep patterns is associated with higher serum malondialdehyde and basal oxidizability status in particular. Further studies are recommended on the cardiometabolic impact of oxidative stress biomarkers in individuals with segmented sleep.

CITATION

Al Lawati I, Zadjali F, Al-Abri MA. Elevated oxidative stress biomarkers in adults with segmented sleep patterns. J Clin Sleep Med. 2024;20(6):959-966.

Circadian rhythm regulates the function of immune cells and participates in the development of tumors

Circadian rhythms are present in almost all cells and play a crucial role in regulating various biological processes. Maintaining a stable circadian rhythm is essential for overall health. Disruption of this rhythm can alter the expression of clock genes and cancer-related genes, and affect many metabolic pathways and factors, thereby affecting the function of the immune system and contributing to the occurrence and progression of tumors. This paper aims to elucidate the regulatory effects of BMAL1, clock and other clock genes on immune cells, and reveal the molecular mechanism of circadian rhythm's involvement in tumor and its microenvironment regulation. A deeper understanding of circadian rhythms has the potential to provide new strategies for the treatment of cancer and other immune-related diseases.

Are sleep time and quality associated with inflammation in children and adolescents? A systematic review

Sleep restriction in children can trigger the development of problems such as impaired cognition, behavioral problems, cardiovascular problems, and obesity. In addition, the inflammatory profile of children can also be influenced by sleep restriction. The aimed to review and analyze the association between time and sleep quality with inflammatory biomarkers in children and adolescents. Three electronic databases (MEDLINE, Web of Science and Scopus) were searched from August 30, 2022. The search strategy used the following descriptors: children and adolescents; sleep, and inflammatory profile. This review protocol is registered in the PROSPERO database (CRD42020188969). We obtained 2.724 results of articles with potentially relevant titles. Sixteen percent of the articles were excluded because they were duplicates, 84.3% were excluded after reading the title, and 0.9% were studied from systematic reviews or textbooks (0.9%). Accelerometers are the most commonly used method for the objective measurement of sleep time, while the PSQI questionnaire is the most commonly used subjective method to measure sleep quality. The results indicated an inconsistent association between sleep time and CRP in the literature. Sixty percent of studies used the Pittsburgh Sleep Quality Index (PSQI) for subjective assessment of sleep quality and possible sleep disorders. However, only one retrieved study showed significant association between sleep quality and CRP. Thus, sleep time does not present significant association with inflammatory biomarkers; whereas, poor sleep quality shows positive association with CRP with a lower magnitude.

Inflammation biomarkers in OSA, chronic obstructive pulmonary disease, and chronic obstructive pulmonary disease/OSA overlap syndrome

STUDY OBJECTIVES

The coexistence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) in a single individual, also known as overlap syndrome (OVS), is associated with higher cardiovascular risk and mortality than either OSA or COPD alone. However, the underlying mechanisms remain unclear. We hypothesized that patients with OVS have elevated systemic inflammatory biomarkers relative to patients with either disease alone, which could explain greater cardiovascular risk observed in OVS.

METHODS

We included 255 participants in the study, 55 with COPD alone, 100 with OSA alone, 50 with OVS, and 50 healthy controls. All participants underwent a home sleep study, spirometry, and a blood draw for high-sensitivity C-reactive protein and total blood count analysis. In a randomly selected subset of 186 participants, inflammatory protein profiling was performed using Bio-Rad Bio-Plex Pro Human Cytokine 27-Plex Assays. Biomarker level differences across groups were identified using a mixed linear model.

RESULTS

Levels of interleukin 6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), and granulocyte colony stimulating factor (G-CSF) were higher in participants with OVS and COPD compared with healthy controls and participants with OSA. Furthermore, participants with OVS had higher circulating levels of leukocytes and neutrophils than those with COPD, OSA, and controls.

CONCLUSIONS

COPD and OVS are associated with higher systemic inflammation relative to OSA and healthy controls. This work proposes the potential utilization of interleukin 6, granulocyte colony stimulating factor, and high-sensitivity C-reactive protein as screening biomarkers for COPD in patients with OSA. Inflammatory pathways may not fully explain the higher cardiovascular risk observed in OVS, indicating the need for further investigation.

CITATION

Sanchez-Azofra A, Gu W, Masso-Silva JA, et al. Inflammation biomarkers in OSA, chronic obstructive pulmonary disease, and chronic obstructive pulmonary disease/OSA overlap syndrome. J Clin Sleep Med. 2023;19(8):1447-1456.

Serum Urotensin II Levels Are Elevated in Patients with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) has become major public concern and is continuously investigated in new aspects of pathophysiology and management. Urotensin II (UII) is a powerful vasoconstrictor with a role in cardiovascular diseases. The main goal of this study was to evaluate serum UII levels in OSA patients and matched controls. A total of 89 OSA patients and 89 controls were consecutively enrolled. A medical history review and physical examination of the participants was conducted, with polysomnography performed in the investigated group. UII levels and other biochemical parameters were assessed according to the standard laboratory protocols. The median AHI in the OSA group was 39.0 (31.4-55.2) events/h, and they had higher levels of hsCRP when compared to control group (2.87 ± 0.71 vs. 1.52 ± 0.68 mg/L; p < 0.001). Additionally, serum UII levels were significantly higher in the OSA group (3.41 ± 1.72 vs. 2.18 ± 1.36 ng/mL; p < 0.001), while positive correlation was found between UII levels and hsCRP (r = 0.450; p < 0.001) and systolic blood pressure (SPB) (r = 0.317; p < 0.001). Finally, multiple regression analysis showed significant association of UII levels with AHI (0.017 ± 0.006, p = 0.013), SBP (0.052 ± 0.008, p < 0.001) and hsCRP (0.538 ± 0.164, p = 0.001). As UII levels were associated with blood pressure and markers of inflammation and OSA severity, it might play an important role in the complex pathophysiology of OSA and its cardiometabolic complications.

A Scoping Review of Sleep Apnea: Where Do We Stand?

Obstructive sleep apnea (OSA), a condition in which there is a recurrent collapse of the upper airway while sleeping, is a widespread disease affecting 5% to 10% people worldwide. Despite several advances in the treatment modalities for OSA, morbidity and mortality remain a concern. Common symptoms include loud snoring, gasping for air during sleep, morning headache, insomnia, hypersomnia, attention deficits, and irritability. Obese individuals, male gender, older age (65+), family history, smoking, and alcohol consumption are well recognized risk factors of OSA. This condition holds the ability to increase inflammatory cytokines, cause metabolic dysfunction, and increase the sympathetic output, all of which exacerbate OSA due to their effect on the cardiovascular system. In this review, we discuss its brief history, risk factors, complications, treatment modalities, and the role of clinicians in curbing its risk.

Sleep duration and biomarkers of inflammation in African American and white participants with a parental history of Alzheimer's disease

Introduction

African Americans (AA)s have worse inflammation, worse sleep, and a greater incidence of Alzheimer's disease (AD) compared to whites; however, no studies have examined associations between biomarkers, sleep, and cognition, and differences by race.

Methods

Seventy-six cognitively normal, middle aged (45-65 years) adults with a parental history of AD were included in this study. Associations between biomarkers (tumor necrosis factor-α [TNF-α], interleukin-10 [IL-10], intercellular adhesion molecule-1 [ICAM-1],, and C-reactive protein [CRP]) and self-reported sleep or cognition measures, were assessed.

Results

Average sleep duration was significantly lower for AA versus whites (average[SD]) in hours: 6.02(1.18) versus 7.23(0.91), P = .000004). We found a statistically significant association between plasma IL-10 and sleep duration (Spearman's ρ = 0.26, P = .04) and CSF ICAM-1 and sleep quality (Spearman's ρ = 0.30, P = .03).

Discussion

Longer sleep duration is positively associated with plasma IL-10 levels irrespective of race. Sleep quality was positively associated with CSF ICAM-1 only in African Americans.

Neighbourhood deprivation and intersectional inequalities in biomarkers of healthy ageing in England

While social and spatial determinants of biomarkers have been reported, no previous study has examined both together within an intersectional perspective. We present a novel extension of quantitative intersectional analyses using cross-classified multilevel models to explore how intersectional positions and neighbourhood deprivation are associated with biomarkers, using baseline UK Biobank data (collected from 2006 to 2010). Our results suggest intersectional inequalities in biomarkers of healthy ageing are mostly established by age 40-49, but different intersections show different relationships with deprivation. Our study suggests that certain biosocial pathways are more strongly implicated in how neighbourhoods and intersectional positions affect healthy ageing than others.

Effects of oral appliances on serum cytokines in adults with obstructive sleep apnea: a systematic review

PURPOSE

This review aimed to evaluate the effects of oral appliance (OA) therapy on serum inflammatory cytokines in adults diagnosed with obstructive sleep apnea (OSA).

METHODS

Seven electronic databases and partial gray literature were searched without restrictions through March 2021. Articles evaluating the levels of serum inflammatory cytokines in patients with OSA after OA treatment were included. The risk of bias (RoB) was assessed using the before-and-after tool or RoB 2.0. The level of certainty was assessed using the GRADE tool.

RESULTS

Five studies met the eligibility criteria. One was a randomized clinical trial (RCT), while four were non-randomized clinical trials (NRCTs). Among the studies, C-reactive protein (CRP), IL-6, IL-10, IL-1β, and tumor necrosis factor α (TNF-α) were investigated. The RCT reported no significant differences in marker levels after 2 months of OA therapy, while the NRCTs showed improvement on CRP, TNF-α, and IL-1β levels after longer follow-up periods. The RoB was evaluated as showing some concern in the RCT. Three NRCTs presented good RoB, and one showed a fair RoB. The level of certainty was graded as moderate quality for inflammatory marker levels assessed in the RCT The levels of certainty evaluated in NRCTs were classified as very low.

CONCLUSIONS

Although limited, existing scientific evidence showed that OA therapy may improve serum cytokine levels in adults with OSA. However, short treatment periods are not effective in reducing markers of systemic inflammation which may require extended time and a decrease of in apneic events to improve.

Poor Diet, Long Sleep, and Lack of Physical Activity Are Associated with Inflammation among Non-Demented Community-Dwelling Elderly

Inflammation in elderly is associated with physical and cognitive morbidity and mortality. We aimed to explore the association of modifiable lifestyle parameters with inflammation among non-demented, community-dwelling elderly. A sub-sample of 117 patients with mild cognitive impairment (MCI, n = 63) and cognitively non-impaired controls (CNI, n = 54) were recruited from a large, population-based cohort in Crete, Greece, of 3140 elders (>60 years old). All participants underwent assessment of medical history/physical examination, extensive neuropsychiatric/neuropsychological evaluation, diet, three-day 24-h actigraphy, subjective sleep, physical activity, and measurement of IL-6 and TNFα plasma levels. Associations between inflammatory markers and diet, objective sleep duration, subjective sleep quality, and lack of physical activity were assessed using multivariate models. Regression analyses in the total group revealed significant associations between TNF-α and low vegetable consumption (p = 0.003), and marginally with objective long nighttime sleep duration (p = 0.04). In addition, IL-6 was associated with low vegetable consumption (p = 0.001) and lack of physical activity (p = 0.001). Poor diet and lack of physical activity appear to be modifiable risk factors of inflammation, whereas long sleep appears to be a marker of increased inflammatory response in elderly. Our findings may have clinical implications given the association of inflammatory response with morbidity, including cognitive decline, and mortality in elderly.

Association between homocysteine, C-reactive protein, lipid level, and sleep quality in perimenopausal and postmenopausal women

This study aimed to investigate the correlation between homocysteine (HCY), C-reactive protein (CRP), lipid levels, and sleep quality in perimenopausal and postmenopausal women.We collected data from 217 patients (perimenopause and postmenopausal) who visited the gynecological endocrine outpatient department of our hospital between January 2017 and January 2019. The quality and patterns of sleep were measured using the Pittsburgh Sleep Quality Index, and relationships between HCY, CRP, lipid levels, and sleep quality were analyzed according to a Pittsburgh Sleep Quality Index ≥ 8.There were significant differences in age, education level, and occupation among patients with different levels of sleep quality (P < .05). HCY, CRP, total cholesterol, triglyceride, and low-density lipoprotein levels were significantly higher in patients with poor sleep quality than in those with good sleep quality (P < .05). Age, education level, occupation, HCY, CRP, and lipid levels (total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein) were all significant influencing factors for sleep quality in perimenopausal and postmenopausal women (all P < .05). After adjusting for age, education level, occupation, HCY, and CRP levels were all significant and independent risk factors for sleep quality in perimenopausal and postmenopausal women (all P < .05).Levels of HCY, CRP, and lipids were significantly correlated with sleep quality in perimenopausal and postmenopausal women. HCY and CRP were identified as independent risk factors for sleep quality in perimenopausal and postmenopausal women, thus providing theoretical support for the clinical improvement of sleep quality.

Putative associations between inflammatory biomarkers, obesity, and obstructive sleep apnea

BACKGROUND:

Previous studies have reported increased levels of inflammatory mediators in patients with obstructive sleep apnea (OSA), but their relation with the severity of OSA is controversial.

OBJECTIVE:

To address potential relationships between OSA-related inflammatory markers, namely, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and fibrinogen, with different oxygenation parameters and with BMI.

METHODS:

All eligible patients with suspected OSA newly referred to the Sleep Medicine Research Center at King Abdulaziz University Hospital, Jeddah, were evaluated demographically and anthropometrically, and underwent overnight polysomnography. Fasting morning blood samples were collected to measure serum levels of CRP, fibrinogen, TNF-α, and IL-6. Potential correlations between these inflammatory mediators and severity measures of OSA and body mass index (BMI) were explored.

RESULTS:

Sixty-four patients completed the study (40 with OSA and 24 without OSA). Significantly increased levels of CRP, fibrinogen, IL-6, and TNF-α emerged in patients with OSA compared to non-OSA. Significant associations between log CRP and log fibrinogen levels emerged with increasing BMI. However, there was no significant association between any of the inflammatory markers and the severity of OSA based on the apnea/hypopnea index or oxyhemoglobin saturation-derived parameters.

CONCLUSIONS:

OSA patients exhibit increased levels of inflammatory mediators that do not appear to be associated with polysomnographic measures, but exhibit positive correlation with the degree of adiposity.

Blood biomarker levels by total sleep duration: cross-sectional analyses in UK Biobank

BACKGROUND

Short or long sleep duration has been associated with some major chronic diseases, but whether disease-related blood biomarkers vary according to habitual sleep duration is unclear. This cross-sectional study aimed to assess blood biomarker levels in relation to total sleep duration.

METHODS

The analysis includes 459,796 white British adults aged 40-69 during 2006-2010 in UK Biobank. At recruitment, blood samples and self-reported information on total sleep duration were collected from participants. A panel of blood biomarkers were measured. Using linear regression, we estimated geometric mean concentrations of blood biomarkers and mean ratio of ApoB/ApoA1 by sleep duration adjusted for sex, age at data collection, time of blood collection, and lifestyle covariates.

RESULTS

Percentage differences in the concentrations of most biomarkers by sleep duration were modest. The largest differences were for C-reactive protein (CRP, an inflammatory biomarker) and gamma glutamyltransferase (GGT, a liver function biomarker), and the differences were markedly attenuated after multivariable-adjustment. The multivariable-adjusted geometric means of CRP and of GGT were 14% and 14% higher in <6 h vs 7-8 h of sleep; and 22% and 12% higher in >9 h vs 7-8 h of sleep, respectively.

CONCLUSION

In white British adults, most blood biomarker levels varied only modestly with sleep duration and the remaining associations may be due to residual confounding.

Association between sleep characteristics, ideal cardiovascular health, and systemic inflammation, NHANES 2017-2018

There is conflicting evidence regarding the associations between sleep deprivation and inflammatory biomarkers indicative of cardiovascular disease risk, such as high-sensitivity C-reactive protein (hsCRP). The association between sleep habits and hsCRP was quantified in a nationally representative sample of adults in the United States and mediation by ideal cardiovascular health metrics was explored. A cross-sectional analysis of cardiovascular disease-free participants aged 20-79 years from the 2017-2018 National Health and Nutrition Examination Survey was conducted. The primary exposures were self-reported sleep duration, sleep debt (difference between the average weekday and weekend sleep duration), and ideal cardiovascular health (11-14 points). The primary outcome was hsCRP (high-risk ≥ 3.0 mg/L). Multivariable robust Poisson models were used to estimate prevalence ratios after multiple imputation. A subgroup analysis of shift workers was also conducted. Of 4027 participants included (mean age 46 years; 52% female; 41% shift workers), the prevalence of sleeping <6 h on weekdays was 9%, with 40% sleeping ≥9 h on weekends. One-quarter had a high (≥2 h) sleep debt, 82% had poor cardiovascular health, and 34% had high-risk hsCRP. There were no significant associations between weekday sleep duration or sleep debt with high-risk hsCRP, even among shift workers. Mediation analysis was not conducted. Ideal cardiovascular health was associated with a lower prevalence of high-risk hsCRP (prevalence ratios, 0.60, 95% CI, 0.48-0.75). The lack of significant associations suggests a complex interrelationship of hsCRP with factors beyond sleep duration. Examination of populations at highest risk of chronic sleep deprivation could help to elucidate the association with systemic inflammation-related outcomes.

The Assessment of Sleep Quality in Patients Following Valve Repair and Valve Replacement for Infective Endocarditis: A Retrospective Study at a Single Center

Background

The aim of this study was to measure sleep quality among patients who underwent infective endocarditis (IE) surgery and identify the risk factors involved in sleep disorders.

Material/Methods

In this study, we used actigraphy, the Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleep Scale (ESS) to determine the clinical characteristics of sleep disorders in 116 patients with IE who were in rehabilitation after surgery.

Results

Our results showed that 46 (39.7%) patients had sleep efficiency over 85%, while 70 (60.3%) patients had sleep efficiency below 85%. The correlation analysis showed that sleep efficiency was related to the duration of the disease, with a longer duration leading to lower sleep efficiency (P=0.031). The sleep efficiency of patients with IE following surgery was also affected by alcohol consumption; however, surprisingly, patients with “heavy” alcohol consumption had higher sleep efficiency (P=0.030). We found a significant correlation between sleep efficiency and postoperative interleukin-6 (IL) levels, C-reactive protein (CRP) levels, and preoperative erythrocyte sedimentation rate (P<0.05). No significant correlation was found between brain natriuretic peptide levels and sleep efficiency, PSQI score, or ESS score. Postoperative hemoglobin (Hb) level was associated with sleep efficiency (R=0.194, P=0.036), but there was no statistically significant correlation between the PSQI and ESS scores. Postoperative alanine transaminase (ALT) showed a significant negative correlation with sleep efficiency (R=−0.27, P=0.003).

Conclusions

We found a high prevalence of sleep disorders in patients with IE along with an increase in inflammatory factors, including postoperative IL-6, CRP, ALT, and Hb levels.

Sleep, inflammation and cognitive function in middle-aged and older adults: A population-based study

BACKGROUND

Sleep plays a key role in preserving cognitive function. However, the optimal strategies of sleep for cognition and the underlying mechanism are not well-established.

METHODS

A cross-sectional study was performed using the China Health and Retirement Longitudinal Study (CHARLS), 2011-2012 survey. Self-reported nighttime sleep and afternoon napping data were collected. Fasting blood collected was analyzed for the high-sensitivity C-reactive protein (CRP) and white blood cell.

RESULTS

Both nighttime sleep and afternoon napping were significantly associated with cognition after adjusting for confounders (p < 0.05). Precisely, participants with nighttime sleep of 6.1-7h had the highest cognition scores (p < 0.05). Participants with less than 30 min afternoon napping had the highest cognition scores (p < 0.05). The synergistic effect of nighttime sleep and afternoon napping was not significant (p > 0.05). Nighttime sleep and afternoon napping were significantly related to the white blood cell, but not the high-sensitivity CRP. The white blood cell mediated the association between sleep and cognition (p < 0.05).

CONCLUSION

Nighttime sleep of six to seven hours and afternoon napping of less than 30 minutes are associated with optimal cognitive function in middle-aged and older people, respectively. Sleep influences cognition partly via the inflammatory profile.

Obstructive sleep apnea is associated with lower adiponectin and higher cholesterol levels independently of traditional factors and other sleep disorders in middle-aged adults: the ELSA-Brasil cohort

PURPOSE

Obstructive sleep apnea (OSA) may contribute to metabolic and inflammatory deregulation but previous studies failed to consider sleep duration, sleep fragmentation, insomnia, and daytime sleepiness as potential confounders.

METHODS

Consecutive non-diabetic middle-aged participants from the ELSA-Brasil cohort were invited to perform a clinical evaluation, home sleep study for 1 night, and wrist actigraphy for 7 days. OSA was defined by an apnea-hypopnea index ≥ 15 events/h. Participants were stratified according to the presence of OSA measuring the following markers: fasting glucose, glucose tolerance test, homeostatic model assessment of insulin resistance (HOMA-IR) index, fasting insulin, insulin after 2 h of glucose load, glycated hemoglobin, total cholesterol and their fractions, triglycerides, C-reactive protein, TNF-alpha, interleukin-6, interleukin-10, leptin, adiponectin, E-selectin, ADMA, MCP-1, TGF, apolipoprotein B, fibrinogen, and lipoprotein(a). Differences between groups were identified by chi-square test and ANOVA.

RESULTS

We studied 708 participants (mean age: 46 ± 5 years, men: 44%, BMI 26.1 ± 4.1 kg/m²). Compared to no OSA, participants with OSA presented higher levels while fasting and after 2 h glucose load of insulin, HOMA-IR, cholesterol, triglycerides, and C-reactive protein (all p < 0.001). After linear regression analysis adjusting for traditional risk factors plus sleep duration, fragmentation, insomnia, and daytime sleepiness, OSA was negatively associated with adiponectin (β = - 0.271 CI 95% - 0.456 - 0.085) and positively associated with cholesterol (β = 9.707 CI 95% 2.737 16.678). Sex-stratification revealed that these associations were significant for men but not women.

CONCLUSIONS

In non-diabetic middle-age adults, men with OSA presented with lower adiponectin and higher cholesterol levels independently of sleep duration, sleep fragmentation, insomnia, and daytime sleepiness.

Increased frequency of sleep problems in children and adolescents with familial Mediterranean fever: The role of anxiety and depression

AIM

Familial Mediterranean fever (FMF) is the most common hereditary autoinflammatory disease. The main goal of our study is to compare sleep habits, depression and anxiety of patients with FMF to healthy children and to determine the influence of disease-related factors on sleep habits and psychiatric symptoms.

METHOD

In total, 323 child and adolescent patients with FMF and 260 healthy peers as a control group were included in this study. Questionnaires were used to evaluate sleep habits, psychological status of children and adolescents with and without FMF.

RESULTS

While there was not a significant difference in terms of age, gender, depression and anxiety scores (P > 0.05); patients with FMF had significantly higher total sleeping score (45.69 ± 7.70 vs 43.31 ± 7.77; P = 0.001). Depression and anxiety scores of patients with FMF who have been experiencing sleep problems were found to be dramatically higher compared to those FMF patients without sleep problems (7.70 ± 5.56 vs 4.59 ± 3.97; P = 0.001; 35.46 ± 18.57 vs 25.22 ± 14.12; P = 0.001; respectively). Patients with FMF who had a disease attack last month had remarkably higher depression, anxiety and sleeping scores compared to those who did not. When FMF patients were compared in terms of exertional leg pain, increased acute phase reactant levels, comorbidity and mutation types, there was not a significant difference for depression, anxiety and sleeping scores.

CONCLUSION

Children and adolescents with FMF experience more sleeping problems compared to healthy children and in presence of sleeping disorders, psychiatric symptoms are seen more frequently. Therefore, evaluation of psychopathology is important if youth with FMF have sleep problems.

Relationship between sleep characteristics and markers of inflammation in Swedish women from the general population

Systemic inflammation is thought to mediate the link between sleep and cardiovascular outcomes, but previous studies on sleep habits and inflammation markers have found inconsistent results. This study investigated the relationship between sleep characteristics and C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor α (TNFα). A representative sample of 319 Swedish women was randomly selected from the general population for in-home polysomnography, sleep questionnaire and blood samples. As variables were highly correlated, principal component analysis was used to reduce the number of original variables. Linear regression with log-transformation of the outcomes (lnCRP, lnIL-6 and lnTNFα) and quantile regression were fitted to estimate cross-sectional relationships. Multivariable linear regression models suggested a significant association of insomnia symptoms (self-reported) with higher lnCRP levels (β = 0.11; 95% confidence interval [CI] = 0.02; 0.21), but not with lnIL-6 and lnTNFα. From quantile regression analysis we found that a high non-restorative index (subjective) and insomnia symptoms (self-reported) were associated with higher values of CRP, especially in the highest quantiles of the CRP distribution (90th percentile: β = 0.71; 95% CI = 0.17; 1.24. β = 1.23; 95% CI = 0.44; 2.02, respectively). Additionally, higher amounts of rapid eye movement (REM) sleep were associated with lower CRP values (90th percentile: β = -0.80; 95% CI = -0.14; -1.46). In conclusion, sleep disturbances (self-reported), specifically difficulties maintaining sleep and early morning awakenings, but not sleep duration (neither subjective nor objective), were associated with higher CRP levels. No association was found with IL-6 or TNFα. Elevated REM sleep was associated with lower CRP levels. The results suggest that inflammation might be an intermediate mechanism linking sleep and health in women.

Obstructive Sleep Apnea, Hypertension, and Cardiovascular Risk: Epidemiology, Pathophysiology, and Management

PURPOSE OF REVIEW

Given the rising prevalence of obstructive sleep apnea (OSA), we aimed to review the epidemiologic and pathophysiologic relationship of OSA, hypertension, and cardiovascular disease, and to summarize recent advances in the treatment of OSA.

RECENT FINDINGS

OSA is associated with an elevated risk of hypertension and cardiovascular disease. Several pathophysiologic factors contribute to the relationship between OSA and vascular risk, including neurohormonal dysregulation, endothelial dysfunction, and inflammation. While CPAP reduces blood pressure, it has not been demonstrated to reduce cardiovascular risk. The combination of CPAP and weight loss has a synergistic effect on blood pressure and several metabolic parameters. Adherence to CPAP is poor across studies, potentially contributing to the attenuation of perceived cardiovascular benefit from CPAP therapy. A greater emphasis on adherence to CPAP and the combination of CPAP and weight loss are central to reducing cardiovascular risk among individuals with OSA.

Long Sleep Duration is Associated with Increased High-Sensitivity C-Reactive Protein: A Nationwide Study on Chinese Population

PURPOSE

High-sensitivity C-reactive protein (hs-CRP) has been shown as an important predictor of cardiovascular risk, and sleep duration is an important factor influencing health outcomes. However, the association between hs-CRP and sleep duration among Chinese adults remained unknown and controversial. We aimed to explore the associations between sleep duration and hs-CRP levels among Chinese adults, and the differences in sex and geographical regions.

METHODS

This cross-sectional study was based on nationally representative Chinese samples from the 2009 China Health and Nutrition Survey, which employed multistage, random cluster designs. Habitual sleep duration was self-reported with short and long sleep duration defined as ≤6h and ≥9h per day, respectively. Participants were divided into 4 groups based on the categories of self-reported sleep duration (≤6h, 7h, 8h, ≥9h per day), excluding hs-CRP levels ≥10 mg/L. Subset samples were stratified by sex and geographical regions.

RESULTS

A total of 8170 Chinese adults with a mean age of 50.0±14.9 years and 4369 (53.5%) men were included. Participants sleeping eight hours had the lowest hs-CRP levels. Long sleep duration (≥9h) was significantly associated with elevated hs-CRP levels after adjusting for multiple covariates in full samples (β=0.0356; 95% CI: 0.0050-0.0663; P=0.0228), but the associations of short sleep duration (≤ 6h) were limited to the unadjusted model. Long sleep duration was associated with elevated hs-CRP levels in women (β= 0.0512; 95% CI: 0.0097-0.0927; P=0.0155) and in the northern region of China (β=0.0699; 95% CI: 0.0210-0.1187; P=0.0051), but not in men or the southern region.

CONCLUSION

Long but not short sleep duration was positively associated with elevated hs-CRP levels, independent from traditional risk factors among Chinese adults, and sex and geographical differences were observed. Our findings imply that modifications of long sleep duration might be added to behavioral therapy to reduce cardiovascular risk in Chinese adults.

Impaired sleep quality is associated with concurrent elevations in inflammatory markers: are post-menopausal women at greater risk?

Abstract

Background

Chronic inflammation and impaired sleep increase the risk for cardiovascular disease. Menopausal women may be particularly at risk as a result of impaired sleep. The objective of the current investigation was to assess the relationship between poor sleep and C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and myeloperoxidase (MPO) in healthy non- and postmenopausal women and men.

Methods

A fasting blood draw was obtained from 122 healthy men and women (31 were postmenopausal). Higher scores on the Pittsburgh Sleep Quality Index (PSQI) were used to define poor sleep. Given the sample size and healthy nature of the sample, hierarchical linear regression analyses were performed on a composite inflammatory score involving CRP, IL-6, and TNF-α. Sex/menopausal group and PSQI were entered as predictors, and the interaction of the group by PSQI was entered stepwise. Analyses on MPO were performed separately.

Results

Sleep quality was associated with higher inflammatory activity (β = 0.272, P = 0.003), which remained significant (P = 0.046) after controlling for age, waist circumference, exercise times per week, and depressive symptoms. While in the same direction, sleep quality was not significantly associated with MPO. Dichotomizing sleep quality led to similar results.

Conclusion

Impaired sleep quality is independently associated with greater inflammation in healthy adult men and women. Despite an overall less favorable metabolic and inflammatory profile in postmenopausal women, impaired sleep did not emerge as differentially related to inflammatory activity in this group.

The Sleep-Immune Crosstalk in Health and Disease

Sleep and immunity are bidirectionally linked. Immune system activation alters sleep, and sleep in turn affects the innate and adaptive arm of our body's defense system. Stimulation of the immune system by microbial challenges triggers an inflammatory response, which, depending on its magnitude and time course, can induce an increase in sleep duration and intensity, but also a disruption of sleep. Enhancement of sleep during an infection is assumed to feedback to the immune system to promote host defense. Indeed, sleep affects various immune parameters, is associated with a reduced infection risk, and can improve infection outcome and vaccination responses. The induction of a hormonal constellation that supports immune functions is one likely mechanism underlying the immune-supporting effects of sleep. In the absence of an infectious challenge, sleep appears to promote inflammatory homeostasis through effects on several inflammatory mediators, such as cytokines. This notion is supported by findings that prolonged sleep deficiency (e.g., short sleep duration, sleep disturbance) can lead to chronic, systemic low-grade inflammation and is associated with various diseases that have an inflammatory component, like diabetes, atherosclerosis, and neurodegeneration. Here, we review available data on this regulatory sleep-immune crosstalk, point out methodological challenges, and suggest questions open for future research.

Sleep characteristics and inflammatory biomarkers among midlife women

Study Objectives

Research suggests that sleep disturbances are associated with elevated levels of inflammation. Some evidence indicates that women may be particularly vulnerable; increased levels of inflammatory biomarkers with sleep disturbances are primarily observed among women. Midlife, which encompasses the menopause transition, is typically reported as a time of poor sleep. We tested whether poorer objectively measured sleep characteristics were related to a poorer inflammatory profile in midlife women.

Methods

Two hundred ninety-five peri- and postmenopausal women aged 40-60 completed 3 days of wrist actigraphy, physiologic hot flash monitoring, questionnaires (e.g. Berlin sleep apnea risk questionnaire], and a blood draw for the assessment of inflammatory markers, including C-reactive protein (CRP), interleukin-6 (IL-6), and von Willebrand factor (VWF) antigen. Associations of objective (actigraphy) sleep with inflammatory markers were tested in regression models. Sleep efficiency was inverse log transformed. Covariates included age, race/ethnicity, education, body mass index, sleep apnea risk, homeostatic model assessment (a measure of insulin resistance), systolic blood pressure, low-density lipoprotein cholesterol, and physical activity.

Results

In separate models controlling for age, race/ethnicity, and education, lower sleep efficiency was associated with higher IL-6 [b(SE) = .02 (.10), p = .003] and VWF [b(SE) = .02 (.08), p = .002]. More minutes awake after sleep onset was associated with higher VWF [b(SE) = .12 (.06), p = .01]. Findings persisted in multivariable models.

Conclusions

Lower sleep efficiency and more minutes awake after sleep onset were independently associated with higher circulating levels of VWF. Lower sleep efficiency was associated with higher circulating levels of IL-6. These findings suggest that sleep disturbances are associated with greater circulating inflammation in midlife women.

Recollections of positive early caregiving relate to sympathetic nervous system activation and chronic inflammation in subsequent generations

To understand links between early experience and biomarkers of peripheral physiology in adulthood, this study examined associations between quality of early caregiving and markers of sympathetic activation and chronic inflammation in a sample of 52 low-income mothers and their preschool-aged children. Mothers reported on levels of positive caregiving experienced during childhood using the Structural Analysis of Social Behavior-Intrex. Mother and child sympathetic activation was indexed via pre-ejection period (PEP) at rest, during a dyadic social engagement task, and for children, while interacting with an unfamiliar adult. C-reactive protein (CRP) was collected using whole blood spots to assess levels of low-grade chronic inflammation. Results showed that mothers who reported experiencing more warm guidance and support for autonomy in early childhood displayed lower resting sympathetic nervous system activation (i.e., longer PEP) and lower chronic inflammation (i.e., CRP levels). Further, lower maternal chronic inflammation levels were associated with lower sympathetic activation (i.e., longer PEP) in their children at rest, and during social interactions with mother and a female stranger.

Physical activity as a moderator for obstructive sleep apnoea and cardiometabolic risk in the EPISONO study

Obstructive sleep apnoea (OSA) is positively associated with cardiometabolic diseases; however, high levels of physical activity could decrease the incidence of OSA and associated comorbidities.

In this study we aimed to examine the incidence of OSA in relation to physical activity, and its role as a protective factor in individuals with OSA on the incidence of cardiometabolic diseases, in an 8–9-year follow-up study. We analysed data of 658 volunteers from the São Paulo Epidemiologic Sleep Study (EPISONO), a cohort study of individuals aged 20–80 years, collected through polysomnography, the International Physical Activity Questionnaire and an assessment of cardiometabolic profile.

Active subjects had a lower risk of developing OSA compared with nonactive subjects (relative risk 0.877, 95% CI 0.296–0.855) and there was a reduced risk of developing type 2 diabetes mellitus in active/apnoeic subjects (relative risk 0.493, 95% CI 0.252–0.961) compared with nonactive subjects. Metabolic equivalent was negatively associated to cardiometabolic markers, such as C-reactive protein (exp(B)=0.720; p=0.001), interleukin-6 (exp(B)=0.991; p=0.03), insulin (exp(B)=0.982; p=0.03), triglycerides (exp(B)=0.997; p<0.001), homeostasis model assessment for insulin resistance (exp(B)≤0.946; p<0.024), quantitative insulin sensitivity check index (exp(B)=992.4; p<0.001) and mean arterial pressure (exp(B)=0.987; p=0.001).

Physical activity was a protective factor against type 2 diabetes mellitus in apnoeic individuals; moreover, being active reduced the risk of developing OSA and was associated with a better cardiometabolic profile.

Response of Blood Parameters to CPAP Treatment in Patients with Obstructive Sleep Apnea

Introduction

Many studies have evaluated the relationship between the NLR and PLR in patients with obstructive sleep apnea (OSA), and have shown that they are related to inflammation. We evaluated whether 3 months of continuous positive airway pressure (CPAP) treatment in patients with moderate to severe OSA without any comorbidities would affect the NLR and PLR values.

Methods

Full blood count parameters were evaluated before and after 3 months of CPAP treatment in patients with a diagnosis of moderate to severe OSA without any comorbidities.

Results

Twenty-nine patients (18 [62.1%] males) were enrolled. The mean body mass index (BMI) was 34.85±5.75 kg/m2, the apnea-hypopnea index score was 49.85±27.42, and CPAP was 9.34±1.77. No significant change in BMI was observed after the third month of treatment. Although the Epworth Sleepiness Scale (ESS) score decreased significantly (p=0.000), no changes were observed in the NLR, PLR, or C-reactive protein level (p>0.05). Mean platelet volume and red blood cell distribution width changed significantly after treatment (p=0.01; p<0.001).

Conclusions

The NLR and PLR did not change after CPAP treatment in patients with moderate to severe OSA without any comorbidities.

Association of sleep duration and sleep quality with the physical, social, and emotional functioning among Australian adults

OBJECTIVES

We aimed to evaluate the interaction of two key determinants of sleep health, quantity and quality, with physical, emotional, and social functioning, in the general population.

DESIGN

Nationally-representative Australian cross-sectional study.

SETTING

General population.

PARTICIPANTS

14,571 people aged 15 or older in Household, Income and Labor Dynamics in Australia (HILDA) in 2013.

MEASUREMENTS

The associations of sleep quality (good/poor) in combination with mid-range (6-8 hours), short (<6) or long (>8) sleep duration with functioning, determined from the SF-36, were evaluated using logistic regression adjusting for sociodemographic, relationships, health behaviors, obesity, pain, and mental and physical illness confounders.

RESULTS

After adjusting for gender, and age, poor sleep quality in combination with short, mid-range and long sleep was associated with worse physical, emotional and social functioning. Pain and comorbid illness explained much of these associations, while attenuation from other covariates was minor. The associations of poor sleep quality with worse functioning remained after full adjustment regardless of sleep duration, while among people with good quality sleep, only those with long sleep duration reported poorer functioning.

CONCLUSIONS

Poor sleep quality has robust associations with worse functioning regardless of total duration in the general population. There appears to be a substantial number of functional short sleepers with good quality sleep.

Acute response to 7-day therapy with CPAP in patients with moderate to severe obstructive sleep apnea and cardiac arrhytmia

INTRODUCTION

Obstructive Sleep Apnea (OSA) has been associated with an elevated risk of cardiac arrhythmia. Continuous positive airway pressure (CPAP) is the selected treatment for moderate to severe OSA and could improve arrhythmias in the long term. However, the acute effect of CPAP has not been studied in detail.

METHODS

We conducted a prospective study with 25 patients with moderate to severe OSA diagnosed by home respiratory polygraphy (RP) and arrhythmia and/or pauses in 24-hour Holter ECG. We analyzed inflammatory parameters and the rate of arrhythmias/pauses after 7 days of auto-adjusting CPAP.

RESULTS

92.5% of the patients were men with a mean age of 61.7±1.9 years. Body mass index (BMI) was 59.5±2.2 kg/m2, with a mean apnea hypopnea index (AHI) of 37.7±3.8 events/hour (ev/h), and a residual AHI (AHIr) of 5.3±0.53 ev/h. After short treatment with CPAP we observed a tendency to improvement in both the severity and number of ventricular extrasystoles (VE) (1595.0±850.3 vs. 926.4±434.5 respectively), pauses and the inflammatory parameters (CRP 3.9±3.1 vs. 1.7±1.2, glycemia 131.4±11.6 vs. 121.9±9.8, HOMA 24.4±3.1 vs. 21.7±2.8, insulin 7.6±1.4 vs. 7.2±1.2 (p>0.5).

CONCLUSION

We didn't find significant changes in pauses, VE and inflammatory parameters with CPAP short therapy in CPAP naive patients recently diagnosed with OSA.

Evaluation of Inflammatory Markers in a Large Sample of Obstructive Sleep Apnea Patients without Comorbidities

Systemic inflammation is important in obstructive sleep apnea (OSA) pathophysiology and its comorbidity. We aimed to assess the levels of inflammatory biomarkers in a large sample of OSA patients and to investigate any correlation between these biomarkers with clinical and polysomnographic (PSG) parameters. This was a cross-sectional study in which 2983 patients who had undergone a polysomnography for OSA diagnosis were recruited. Patients with known comorbidities were excluded. Included patients (n = 1053) were grouped according to apnea-hypopnea index (AHI) as mild, moderate, and severe. Patients with AHI < 5 served as controls. Demographics, PSG data, and levels of high-sensitivity C-reactive protein (hs-CRP), fibrinogen, erythrocyte sedimentation rate (ESR), and uric acid (UA) were measured and compared between groups. A significant difference was found between groups in hs-CRP, fibrinogen, and UA. All biomarkers were independently associated with OSA severity and gender (p < 0.05). Females had increased levels of hs-CRP, fibrinogen, and ESR (p < 0.001) compared to men. In contrast, UA levels were higher in men (p < 0.001). Our results suggest that inflammatory markers significantly increase in patients with OSA without known comorbidities and correlate with OSA severity. These findings may have important implications regarding OSA diagnosis, monitoring, treatment, and prognosis. This trial is registered with ClinicalTrials.gov number NCT03070769.

Biomarkers in Sleep Apnea and Heart Failure

PURPOSE OF REVIEW

Sleep-disordered breathing (SDB) is highly prevalent in heart failure (HF) and may confer significant stress to the cardiovascular system and increases the risk for future cardiovascular events. The present review will provide updates on the current understanding of the relationship of SDB and common HF biomarkers and the effect of positive airway pressure therapy on these biomarkers, with particular emphasis in patients with coexisting SDB and HF.

RECENT FINDINGS

Prior studies have examined the relationship between HF biomarkers and SDB, and the effect of SDB treatment on these biomarkers, with less data available in the context of coexisting SDB and HF. Overall, however, the association of SDB and circulating biomarkers has been inconsistent. Further research is needed to elucidate the relationship between biomarkers and SDB in HF, to evaluate the clinical utility of biomarkers over standard methods in large, prospective studies and also to assess the impact of treatment of SDB on these biomarkers in HF via interventional studies.

Hypoxia and inflammation indicate significant differences in the severity of obstructive sleep apnea within similar apnea-hypopnea index groups

PURPOSE

We determined whether hypoxia parameters are associated with C-reactive protein (CRP), mean platelet volume (MPV), white matter hyperintensity (WMH), and the severity of obstructive sleep apnea (OSA), and also evaluated whether hypoxia parameters, CRP, MPV, and WMH differ in patients with similar apnea-hypopnea index (AHI) scores.

METHODS

A total of 297 patients, who were evaluated using polysomnography, were assessed retrospectively. The measured hypoxia parameters included total sleep time with oxygen saturation <90% (ST₉₀), percentage of cumulative time with oxygen saturation <90% (CT₉₀), and lowest oxygen saturation (min SaO₂). The patients were divided into subgroups according to their CT₉₀ values, and patients with different AHI severities were divided into subgroups according to their ST₉₀ and min SaO₂ levels.

RESULTS

Hypoxia parameters are associated with CRP, MPV, WMH, and the severity of OSA (P < 0.05). The hypoxia parameters differed in all subgroup analyses of similar AHI groups (P < 0.001), and CRP differed only in severe OSA (P < 0.008, P < 0.001). In subgroup analyses of similar AHI groups, MPV and WMH were not significantly different (P > 0.05). Above the hypoxia threshold (CT₉₀ ≥ 10%) of CRP, MPV increased significantly and the presence of WMH increased twofold.

CONCLUSIONS

These data suggest that increased hypoxia severity may mediate increased inflammation and activation of platelets and contribute to the pathogenesis of WMH in patients with OSA. In addition, patients with severe OSA may show significant variability in inflammation and vascular risk. Further prospective data are needed.

Concurrent presence of inflammation and obstructive sleep apnea exacerbates the risk of metabolic syndrome: A KoGES 6-year follow-up study

Obstructive sleep apnea (OSA) leads to multiple end-organ morbidities that are mediated by the cumulative burden of oxidative stress and inflammation. Both OSA and inflammation play key roles in increased risk of cardiovascular disease (CVD). Thus, we hypothesized that the combination of inflammation and OSA could accelerate the development of metabolic syndrome (MetS) in a large cohort study.A total of 1835 participants were randomly selected from the ongoing Korean Genome and Epidemiology Study for the years between 2007 and 2015. Overnight polysomnography was performed on each participant. Blood was drawn for biochemical analyses. Participants with high or low inflammation were divided by high-sensitivity C-reactive protein (hsCRP). MetS was defined using the criteria of the modified National Cholesterol Education Program, Adult Treatment Panel III.The prevalence of MetS was higher among the subjects with OSA and high hsCRP levels than among the other corresponding groups. The incidence of MetS among the 4 groups stratified by OSA and inflammation status at the 6-year follow-up was 11.8%, 19.9%, 25.8%, and 36.0% (HsCRP[-]/OSA[-] vs HsCRP[+]/OSA[-] vs HsCRP[-]/OSA[+] vs HsCRP[+]/OSA[+], P < 0.01). After adjusting for age, sex, smoking, alcohol status, BMI, and change in BMI (ΔBMI) in a multiple logistic regression, the subjects with OSA and high hsCRP levels at follow-up had a 2.22-fold risk of developing MetS, as compared with those with no-OSA and low hsCRP levels (P < 0.01).MetS is more prevalent in the concurrent presence of inflammation and OSA. The combination of these conditions is associated with higher risk of MetS. Additional research is needed to help further define the significance of the combined effect of OSA and subclinical inflammation on the development of MetS in the context of reduction of CVD risk.

Associations of Self-Reported Sleep Quality with Circulating Interferon Gamma-Inducible Protein 10, Interleukin 6, and High-Sensitivity C-Reactive Protein in Healthy Menopausal Women

Introduction

Sleep disturbance is very common in menopausal women and poor sleep quality has been linked to systemic inflammation. However, the impact of poor sleep quality on health outcomes of menopausal women remains unclear. This study evaluated the relationships between sleep quality and inflammation in menopausal women.

Participants and design

This cross-sectional study enrolled 281 healthy women aged 45 to 60 years. The Pittsburgh Sleep Quality Index (PSQI) was used to measure quality of sleep. Multiplex assays were used to measure the levels of 9 cytokines in morning fasting plasma samples. Other variables measured in this study included clinical characteristics and high-sensitivity C-reactive protein (hs-CRP).

Setting

The study was performed at a medical center.

Results

The 281 participants comprised 79 (28%) perimenopausal women and 202 (72%) postmenopausal women. Global PSQI scores were positively correlated with plasma hs-CRP levels (P = 0.012) and were marginally associated with interferon gamma-inducible protein-10 (IP10), interleukin 6 (IL6), and macrophage inflammatory protein-1beta (MIP-1β) levels. After adjusting for age, body mass index, menopause duration, and follicle stimulating hormone, multiple linear regression analysis revealed that high PSQI scores and sleep efficiency < 65% were associated with elevated plasma levels of hs-CRP, IP10, and IL6. In addition, sleep duration < 5 hours was associated with high hs-CRP levels.

Conclusion

Our data show that poor sleep quality and low sleep efficiency are associated with elevated levels of circulating inflammatory factors IP10, IL6 and hs-CRP and that short sleep duration is associated with high levels of hs-CRP in menopausal women. These findings provide novel evidence that poor sleep quality is linked to low-grade systemic inflammation in menopausal women.

The relationship between sleep apnea, metabolic dysfunction and inflammation: The gender influence

Obstructive sleep apnea (OSA) has been associated with increased risk of cardiovascular morbidity and mortality. Although inflammatory markers may mediate this association, it is unknown the influence of gender in this mechanism. Thus, we aimed to evaluate the interaction effects between OSA and gender on metabolic and inflammatory profile in a population sample. This study is part of EPISONO cohort, in which 1042 participants underwent polysomnography, answered questionnaires, and had their blood collected for analysis of fasting glucose, total cholesterol and fractions, leptin, ghrelin, liver transaminases, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and C-reactive protein. The results showed that men with OSA had higher leptin levels, shorter sleep latency and lower N3 sleep stage compared to men control (CTRL). They also presented higher apnea index and number of central apneas compared to both CTRL men and OSA women. In women, OSA was related to longer REM sleep latency, higher apnea-hypopnea index (AHI) during REM sleep and increased TNF-α levels compared to CTRL women. A multivariate model showed that male gender, ghrelin and total cholesterol were negatively associated with TNF-α, while IL-6, triglycerides and hypopnea index were positively associated (R²=0.21). Additionally, gender (men), body mass index, ghrelin, apnea index and smoking were positive predictors of leptin levels (R²=0.55). Of note, postmenopause was associated with changes observed in both TNF-α and AHI during REM sleep in women with OSA. Taken together, our study suggests that OSA consequences may differ between genders and this could indicate a need for different OSA management in women according to their reproductive life's stage.

Sleep Health: Reciprocal Regulation of Sleep and Innate Immunity

Sleep disturbances including insomnia independently contribute to risk of inflammatory disorders and major depressive disorder. This review and overview provides an integrated understanding of the reciprocal relationships between sleep and the innate immune system and considers the role of sleep in the nocturnal regulation of the inflammatory biology dynamics; the impact of insomnia complaints, extremes of sleep duration, and experimental sleep deprivation on genomic, cellular, and systemic markers of inflammation; and the influence of sleep complaints and insomnia on inflammaging and molecular processes of cellular aging. Clinical implications of this research include discussion of the contribution of sleep disturbance to depression and especially inflammation-related depressive symptoms. Reciprocal action of inflammatory mediators on the homeostatic regulation of sleep continuity and sleep macrostructure, and the potential of interventions that target insomnia to reverse inflammation, are also reviewed. Together, interactions between sleep and inflammatory biology mechanisms underscore the implications of sleep disturbance for inflammatory disease risk, and provide a map to guide the development of treatments that modulate inflammation, improve sleep, and promote sleep health.

Cystatin C Levels in Middle-Aged Patients with Obstructive Sleep Apnea Syndrome

Background. Obstructive sleep apnea syndrome (OSAS) is associated with systemic inflammation and increased risk of cardiovascular and chronic kidney disease. Cystatin C (Cyst C) is a novel biomarker of both latent renal damage and cardiovascular disease. Aim of the study was to measure serum levels of Cyst C, as well as IL-8 and CRP, in otherwise healthy OSAS patients. Methods. 84 individuals examined with polysomnography for OSAS symptoms without known comorbidities were prospectively recruited. Results. According to apnea hypopnea index (AHI) subjects were divided in two groups: OSAS group (AHI > 5/hour, n = 64) and controls (AHI < 5/hour, n = 20), which were age- and BMI-matched. Cyst C levels were higher in OSAS patients versus controls (1176.13 ± 351.33 versus 938.60 ± 245.83 ng/mL, resp.; p = 0.017) while serum IL-8 and CRP levels did not differ significantly. Positive correlation was found between Cyst C levels and respiratory disturbance index (RDI) (r = 0.240, p = 0.039) and percentage of time with oxygen saturation <90% (r = 0.290, p = 0.02) and negative correlation was found between Cyst C levels and average oxygen saturation during sleep (r = -0.291, p = 0.012). After adjustment for age and BMI, RDI was the only independent predictor of Cyst C levels (β = 0.256, p = 0.039). Conclusion. Cyst C serum levels are increased in OSAS patients without comorbidities, suggesting an increased renal and cardiovascular disease risk.

Obstructive Sleep Apnea Is Associated with Elevated High Sensitivity C-Reactive Protein Levels Independent of Obesity: Korean Genome and Epidemiology Study

Obstructive sleep apnea syndrome (OSA) has been recognized as a common health problem, and increasing obesity rates have led to further remarkable increases in the prevalence of OSA, along with more prominent cardiovascular morbidities. Though previous studies have reported an independent relationship between elevated high sensitivity C-reactive protein (hsCRP) levels and OSA, the issue remains controversial owing to inadequate consideration of obesity and various confounding factors. So far, few population based studies of association between OSA and hsCRP levels have been published. Therefore, the purpose of the present study was to investigate whether OSA is associated with increased hsCRP levels independent of obesity in a large population-based study. A total of 1,835 subjects (968 men and 867 women) were selected from a larger cohort of the ongoing Korean Genome and Epidemiology Study (KoGES). Overnight polysomnography was performed on each participant. All participants underwent anthropometric measurements and biochemical analyses, including analysis of lipid profiles and hsCRP levels. Based on anthropometric data, body mass index (BMI) and waist hip ratio (WHR) were calculated and fat mass (FM) were measured by means of multi-frequency bioelectrical impedance analysis (BIA). Mild OSA and moderate to severe OSA were defined by an AHI >5 and ≥15, respectively. The population was sub-divided into 3 groups based on the tertile cut-points for the distribution of hsCRP levels. The percentage of participants in the highest tertile of hsCRP increased dose-dependently according to the severity of OSA. After adjustment for potential confounders and obesity-related variables (BMI, WHR, and body fat) in a multiple logistic model, participants with moderate to severe OSA had 1.73-, 2.01-, and 1.61-fold greater risks of being in the highest tertile of hsCRP levels than participants with non-OSA, respectively. Interaction between obesity (BMI ≥25kg/m²) and the presence of moderate-to-severe OSA was significant on the middle tertile levels of hsCRP (OR = 2.4), but not on the highest tertile, compared to the lowest tertile. OSA is independently associated with elevated hsCRP levels and may reflect an increased risk for cardiovascular morbidity. However, we found that OSA and obesity interactively contribute to individuals with general levels of hsCRP (<1.01 mg/dl). The short-term and long-term effects of elevated hsCRP levels on cardiovascular risk in the context of OSA remain to be defined in future studies.

Upper airway and systemic inflammation in obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is associated with pharyngeal inflammation, but the coexistence of systemic inflammation is controversial. This study investigated whether local and systemic inflammatory biomarkers are related in patients with OSA. An uncontrolled extension to the study assessed the response to effective treatment.We recruited 89 patients with OSA (apnoea/hypopnoea index (AHI) ≥5 events·h^-1), 28 snorers and 26 healthy controls. Pharyngeal lavage (PHAL) and plasma samples were collected at baseline and after a 1-year follow-up. Inflammatory cells were evaluated by flow cytometry; interleukin (IL)-6, IL-8 and tumour necrosis factor-α were evaluated by immunoassay.In PHAL, CD4⁺ T-cells, IL-6 and IL-8 were higher in OSA patients than in snorers or healthy controls (p<0.05). The AHI correlated with CD4⁺, IL-6 and IL-8 in PHAL (all p-values <0.05). There were no differences in the inflammatory biomarkers in plasma between the study groups and no relationship between plasma and PHAL biomarkers. Biomarkers decreased significantly in PHAL but not in plasma after 1 year of therapy with continuous positive airway pressure or surgery.In patients with OSA, increased levels of inflammatory biomarkers were found in PHAL, which were reduced with effective treatment. No simultaneous increase in plasma inflammatory biomarkers was found.

Actigraphy- and Polysomnography-Measured Sleep Disturbances, Inflammation, and Mortality Among Older Men

OBJECTIVES

To evaluate whether objectively measured sleep characteristics are associated with mortality risk independent of inflammatory burden and comorbidity.

METHODS

The Osteoporotic Fractures in Men Sleep Study (conducted in 2003-2005) included community-dwelling older men (n = 2531; average [standard deviation {SD}] age = 76.3 (5.5) years). Sleep measures from in-home polysomnography and wrist actigraphy and assessments of serum inflammatory markers levels (C-reactive protein, interleukin-6, tumor necrosis factor α, tumor necrosis factor α soluble receptor II, and interferon-γ) were obtained. Vital status was ascertained over an average (SD) follow-up of 7.4 (1.9 SD) years.

RESULTS

Three of the seven main sleep measures examined were independently associated with greater inflammatory burden. Mortality risk associated with prolonged (≥10% total sleep time) blood oxygen desaturation and short (<5 hours) sleep duration was attenuated to nonsignificance after adjusting for inflammatory burden or medical burden/lifestyle factors. Severe blood oxygen desaturation (adjusted hazard ratio [aHR] = 1.57, 95% confidence interval [CI] = 1.11-2.22), sleep fragmentation (aHR = 1.32, 95% CI = 1.12-1.57), and a lower percentage of sleep in rapid eye movement (aHR per SD = 0.90, 95% CI = 0.93-0.97) were independently associated with mortality.

CONCLUSIONS

Short sleep duration and prolonged blood oxygen desaturation were independently associated with inflammatory burden, which attenuated associations between these sleep characteristics and mortality. Medical and life-style factors also substantially attenuated most sleep-mortality associations, suggesting complex relations between sleep, inflammation, and disease. Sleep fragmentation, severe blood oxygen desaturation, and the percentage of sleep time in rapid eye movement were independently related to mortality risk. Future studies with repeated measures of mediators/confounds will be necessary to achieve a mechanistic understanding of sleep-related mortality risk.

Sleep Disturbance, Sleep Duration, and Inflammation: A Systematic Review and Meta-Analysis of Cohort Studies and Experimental Sleep Deprivation

BACKGROUND

Sleep disturbance is associated with inflammatory disease risk and all-cause mortality. Here, we assess global evidence linking sleep disturbance, sleep duration, and inflammation in adult humans.

METHODS

A systematic search of English language publications was performed, with inclusion of primary research articles that characterized sleep disturbance and/or sleep duration or performed experimental sleep deprivation and assessed inflammation by levels of circulating markers. Effect sizes (ES) and 95% confidence intervals (CI) were extracted and pooled using a random effect model.

RESULTS

A total of 72 studies (n > 50,000) were analyzed with assessment of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor α (TNFα). Sleep disturbance was associated with higher levels of CRP (ES .12; 95% CI = .05-.19) and IL-6 (ES .20; 95% CI = .08-.31). Shorter sleep duration, but not the extreme of short sleep, was associated with higher levels of CRP (ES .09; 95% CI = .01-.17) but not IL-6 (ES .03; 95% CI: -.09 to .14). The extreme of long sleep duration was associated with higher levels of CRP (ES .17; 95% CI = .01-.34) and IL-6 (ES .11; 95% CI = .02-20). Neither sleep disturbances nor sleep duration was associated with TNFα. Neither experimental sleep deprivation nor sleep restriction was associated with CRP, IL-6, or TNFα. Some heterogeneity among studies was found, but there was no evidence of publication bias.

CONCLUSIONS

Sleep disturbance and long sleep duration, but not short sleep duration, are associated with increases in markers of systemic inflammation.

Sleep and Inflammation During Adolescence

OBJECTIVE

To investigate the associations between objective and subjective dimensions of adolescent sleep and C-reactive protein (CRP), a key biomarker of inflammation that predicts chronic health problems in adulthood, and whether the associations vary as a function of adolescents' age.

METHODS

A total of 315 adolescents (14.5-18.4 years) wore wrist actigraphs at night to objectively estimate their sleep duration and variability across nights, and completed the Pittsburgh Sleep Quality Index to assess their subjective sleep quality. CRP levels were assayed from dried blood spots obtained from finger pricks. To control for adiposity, age- and sex-specific body mass index percentiles were obtained from height and weight measurements.

RESULTS

Nightly variability in sleep duration was associated with higher levels of CRP (b = 0.13, p = .045). Shorter average sleep duration was associated with higher CRP, but only among younger adolescents (b = -0.11, p = .041). Subjective sleep quality was not associated with CRP.

CONCLUSIONS

The association of sleep with inflammation during adolescence seems more evident in objective dimensions of sleep duration and variability than in the subjective dimensions of sleep quality. Insufficient sleep may be particularly consequential for younger adolescents.