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

Genetic evidence for the causal effects of C-reactive protein on self-reported habitual sleep duration

Inflammatory responses to acute stimuli are proposed to regulate sleep, but the relationship between chronic inflammation and habitual sleep duration is elusive. Here, we study this relation using genetically predicted level of chronic inflammation, indexed by CRP and IL6 signaling, and self-reported sleep duration. By Mendelian randomization analysis, we show that elevated CRP level within <10 mg/L has a homeostatic effect that facilitates maintaining 7-8 h sleep duration per day - making short-sleepers sleep longer (p = 2.42 × 10-2) and long-sleepers sleep shorter (1.87 × 10-7); but it is not associated with the overall sleep duration (p = 0.17). This homeostatic effect replicated in an independent CRP dataset. We observed causal effects of the soluble interleukin 6 receptor and gp130 on overall sleep duration (p = 1.62 × 10-8, p = 2.61 × 10-58, respectively), but these effects disappeared when CRP effects were accounted for in the model. Using polygenic score analysis, we found that the homeostatic effect of CRP on sleep duration stems primarily from the genetic variants within the CRP gene region: when genetic variants outside of this region were used to predict CRP levels, the opposite direction of effect was observed. In conclusion, we show that elevated CRP level may causally facilitate maintaining an optimal sleep duration that is beneficial to health, thus updating our current knowledge of immune regulation on sleep.

The association between energy-adjusted dietary inflammatory index and physical activity with sleep quality: a cross-sectional study

BACKGROUND

The study aimed to assess the independent and interactive association of energy-adjusted dietary inflammatory index (E-DII) and physical activity (PA) with sleep quality.

METHOD

A cross-sectional study was conducted on the 2466 participants (60% women). A 116-item food frequency questionnaire (FFQ) was applied to calculate E-DII, the International Physical Activity Questionnaire (IPAQ) long form for PA, and the Pittsburgh sleep quality index (PSQI) to assess sleep quality were collected via interview. Multivariate logistic regression was applied to assess independent and interactive associations of E-DII and PA with sleep quality.

RESULT

No significant association was observed between E-DII and sleep quality (OR: 0.96, 95% CI: 0.92_1.01). Also, there was no significant association between the levels of PA and sleep quality. Women had 70% increased odds for poor sleep quality (OR: 1.7, 95% CI: 1.39_2.09) compared with men. No interactive association was observed between E-DII and PA levels with sleep quality.

CONCLUSION

No significant association was observed between E-DII and PA levels with sleep quality. The study indicates a gender difference in sleep quality. Future prospective studies are required to confirm these findings.

Unveiling the sleep-cardiovascular connection: Novel perspectives and interventions-A narrative review

Introduction

Sleep is an important neurophysiological condition that is intricately linked to general health, laying the basis for both physiological and psychological well-being. A thorough examination of sleep disorders and cardiovascular health demonstrates their deep relationship, emphasizing the numerous diagnostic tools and treatment techniques available.

Aim

This study aims to examine the impact, mechanisms, diagnostic techniques, treatment strategies, implications, and healthcare interventions of the sleep-cardiovascular connection, to better understand the relationship between sleep disorders and cardiovascular health.

Methods

The paper reviews key studies conducted from 2015-till date, investigating the impact of sleep disorders on the cardiovascular system. It looked into data relating to cardiovascular outcomes based on the degree of sleep disorders, considered potential confounding factors, and addressed current research constraints.

Results

The findings highlight a strong link between sleep problems and poor cardiovascular outcomes. Emerging diagnostic tools, such as enhanced sleep-related technology and biomarkers, open up new avenues for determining the impact of sleep disturbances on cardiovascular health. In addition, the research discusses several treatment options, ranging from cognitive behavioral therapy to pharmaceutical therapies, and their potential benefits in addressing sleep-related cardiovascular risks.

Conclusion

The complex association between sleep disturbances and cardiovascular health emphasizes the need to recognize sleep as a critical component of overall well-being. Thus collaboration among medical disciplines, as well as individualized therapies, are critical to improving patient care. Moreover, Understanding and managing the consequences of sleep problems on cardiovascular health can lead to more effective interventions, better outcomes, and improved public health as research advances.

The Polysomnographical Meaning of Changed Sleep Quality-A Study of Treatment with Reduced Time in Bed

BACKGROUND

Reports of poor sleep are widespread, but their link with objective sleep (polysomnography-PSG) is weak in cross-sectional studies. In contrast, the purpose of this study was to investigate the association between changes in subjective and objective sleep variables using data from a study of the reduction in time in bed (TIB).

METHODS

One sleep recording was carried out at baseline and one at treatment week 5 (end of treatment) (N = 34).

RESULTS

The Karolinska Sleep Quality Index improved and was correlated with improvement in sleep efficiency (r = 0.41, p < 0.05) and reduction in TIB (r = -0.47, p < 0.01) and sleep latency (r = 0.36, p < 0.05). The restorative sleep index showed similar results. Improvements in the insomnia severity index (ISI) essentially lacked correlations with changes in the PSG variables. It was suggested that the latter may be due to the ISI representing a week of subjective sleep experience, of which a single PSG night may not be representative.

CONCLUSIONS

It was concluded that changes in the subjective ratings of sleep are relatively well associated with changes in the PSG-based sleep continuity variables when both describe the same sleep.

Sleep disturbance, but not depression severity, is associated with inflammation in children and adolescents

STUDY OBJECTIVES

We aimed to examine the association between self-rated and clinician-rated sleep disturbances and C-reactive protein (CRP), an objective marker of inflammation, in pediatric depression.

METHODS

Two hundred fifty-six children and adolescents (15.2 ± 1.6 y, 72.3% female) with moderate to severe symptoms of depression participated in the study. Sleep disturbances were assessed by self-reports (Insomnia Severity Index) and clinician ratings (Kiddie-Schedule for Affective Disorder and Schizophrenia), inflammation by plasma CRP levels.

RESULTS

Higher levels of CRP correlated positively with clinician-rated middle insomnia and hypersomnia. After adjusting for control variables (body mass index, tobacco, alcohol, stress, age, sex, antidepressants, sleep medication, depression severity), regression models confirmed the significant association of clinician-rated hypersomnia and middle insomnia symptoms with elevated CRP levels. In the adjusted regression models, other clinician-rated manifestations of sleep disturbance (eg, initial insomnia) and insomnia self-ratings were not significantly associated with CRP. Body mass index correlated positively with CRP, but body mass index had no mediating effect on the associations between sleep disturbances and CRP. We did not find an association between depression severity, assessed by the Children's Depression Rating Scale-Revised, and CRP.

CONCLUSIONS

Results of the present study indicate a significant association of hypersomnia and middle insomnia symptoms with CRP in pediatric depression, not linked to alterations in the body mass index.

CITATION

Strumberger MA, Häberling I, Emery S, et al. Sleep disturbance, but not depression severity, is associated with inflammation in children and adolescents. J Clin Sleep Med. 2023;19(10):1775-1784.

What do women mean by poor sleep? A large population-based sample with polysomnographical indicators, inflammation, fatigue, depression, and anxiety

Survey studies indicate that reports of disturbed sleep are prevalent and may be prospectively linked to several major diseases. However, it is not clear what self-reported disturbed sleep represents, since the link with objective sleep measures (polysomnography; PSG) seems very weak. The purpose of the present study was to try to investigate what combination of variables (PSG, inflammation, fatigue, anxiety, depression) that would characterize those who complain of disturbed sleep. This has never been done before. Participants were 319 women in a population-based sample, who gave ratings of sleep quality, fatigue, depression, and anxiety, then had their sleep recorded at home, and had blood drawn the following morning for analysis of immune parameters. Correlations and hierarchical multivariable regression analyses were applied to the data. For ratings of difficulties initiating sleep, the associations in the final step were ß = .22, (p < .001) for fatigue, ß = 0.22 (p < .001) for anxiety, and ß = 0.17 (p < .01) for sleep latency, with R2 = 0.14. The rating of repeated awakenings was associated with fatigue (ß = 0.35, p < .001) and C-reactive protein (CRP) (ß = 0.12, p < .05), with R2 = 0.19. The rating of early morning awakenings was associated with fatigue (ß = 0.31, p < .001), total sleep time (TST) (ß = -0.20, p < .01), and CRP (ß = 0.15, p < .05), with R2 = 0.17. Interleukin-6 and Tumour Necrosis Factor were not associated with ratings of sleep problems. The results indicate that subjective fatigue, rather than objective sleep variables, is central in the perception of poor sleep, together with CRP.

Poor sleep quality, insomnia, and short sleep duration before infection predict long-term symptoms after COVID-19

BACKGROUND

Millions of COVID-19 survivors experience a wide range of long-term symptoms after acute infection, giving rise to serious public health concerns. To date, few risk factors for post-COVID-19 conditions have been determined. This study evaluated the role of pre-infection sleep quality/duration and insomnia severity in the incidence of long-term symptoms after COVID-19.

MATERIAL AND METHODS

This prospective study involved two assessments (April 2020 and 2022). At the baseline (April 2020), sleep quality/duration and insomnia symptoms in participants without current/prior SARS-CoV-2 infection were measured using the Pittsburgh Sleep Quality Index (PSQI) and the Insomnia Severity Index (ISI). At the follow-up (April 2022), we asked a group of COVID-19 survivors to retrospectively evaluate the presence of twenty-one symptoms (psychiatric, neurological, cognitive, bodily, and respiratory) that have been experienced one month (n = 713, infection in April 2020-February 2022) and three months after COVID-19 (n = 333, infection in April 2020-December 2021). In April 2022, participants also reported how many weeks passed to fully recover from COVID-19. Zero-inflated negative binomial models were used to estimate the effect of previous sleep on the number of long-term symptoms. Binomial logistic regressions were performed to evaluate the association between sleep variables, the incidence of each post-COVID-19 symptom, and the odds of recovery four/twelve weeks after infection.

RESULTS

Analyses highlighted a significant effect of pre-infection sleep on the number of symptoms one/three months after COVID-19. Previous higher PSQI and ISI scores, and shorter sleep duration significantly increased the risk of almost every long-term symptom at one/three months from COVID-19. Baseline sleep problems were also associated with longer recovery times to return to the pre-infection daily functioning level after COVID-19.

CONCLUSIONS

This study suggested a prospective dose-dependent association between pre-infection sleep quality/quantity and insomnia severity with the manifestation of post-COVID-19 symptoms. Further research is warranted to determine whether preventively promoting sleep health may mitigate the COVID-19 sequelae, with substantial public health and societal implications.

Insomnia symptoms predict longer COVID-19 symptom duration

OBJECTIVE

/Background: The goal of the present study was to assess the prevalence and incidence of insomnia in the United States during the COVID-19 pandemic, and whether, among those that contracted COVID-19, insomnia predicted worse outcomes (e.g., symptoms of greater frequency, duration, or severity).

METHODS

A nationwide sample of 2980 adults living in the United States were surveyed online at two points during the COVID-19 pandemic (T1 = April-June 2020; T2 = January-March 2021). Insomnia symptoms were assessed at both time points using the Insomnia Severity Index (ISI). The T2 survey also asked questions regarding COVID-19 testing and symptoms.

RESULTS

The prevalence of insomnia (defined as ISI ≥15) was 15% at T1 and 13% at T2. The incidence rate of insomnia (i.e., new cases from T1 to T2) was 5.6%. Participants with insomnia were not more likely to contract COVID-19 relative to those participants without insomnia. Among those participants in our sample that contracted the virus during the study interval (n = 149), there were no significant group differences in COVID-19 symptom outcomes, with one exception, participants with insomnia were more likely to report a longer symptom duration (insomnia = 24.8 sick days, no insomnia = 16.1 sick days).

CONCLUSIONS

The present study suggests the prevalence of insomnia in the U.S. population remained high during the COVID-19 pandemic. The data also support that insomnia may be related to experiencing more chronic COVID-19 symptoms. These findings have more general implications for the role of sleep and insomnia on immune functioning.