Sleep fragmentation and sleep-disordered breathing in individuals living close to main roads: results from a population-based study

Effect of external sleep disturbance on sleep architecture in perimenopausal and postmenopausal women

OBJECTIVE

This study aimed to use external sleep disturbance as a model to evaluate sleep architecture in climacteric women before and after menopausal hormone therapy (MHT).

METHODS

Seventeen perimenopausal and 18 postmenopausal women underwent a polysomnography protocol: an adaptation night, a reference night and a sleep disturbance night with one hand loosely tied to the bed for blood sampling. The sleep architecture of the reference and disturbance nights were compared. The 24-h urinary free cortisol concentration (UFC) was measured. The procedure was repeated after 6 months on MHT or placebo.

RESULTS

Fifteen perimenopausal and 17 postmenopausal women completed the study. The perimenopausal and postmenopausal groups were combined. During external sleep disturbance, sleep was shorter and more fragmented; with less stage 2, slow-wave and rapid eye movement (REM) sleep and more wake time and awakenings, both at baseline and after the treatment period. Compared to the placebo group, sleep disturbance was minor for women on MHT: sleep was not shortened and the amount of slow-wave sleep did not decrease. Increased 24-h UFC was observed only during MHT.

CONCLUSIONS

Sleep in climacteric women is easily disturbed, leading to shorter and more fragmented sleep with less deep sleep and REM sleep. Six months of MHT attenuates the observed sleep disturbance.

Multidimensional Environmental Factors and Sleep Health for Aging Adults: A Focused Narrative Review

The timing, amount, and quality of sleep are critical for an individual's health and quality of life. This paper provides a focused narrative review of the existing literature around multidimensional environments and sleep health for aging adults. Five electronic databases, Scopus, Web of Science, PubMed/Medline; EBSCOhost, PsycINFO (ProQuest), and Google Scholar yielded 54,502 total records. After removing duplicates, non-peer reviewed academic articles, and nonrelevant articles, 70 were included for review. We were able to categorize environmental factors into housing security, home environment, and neighborhood environment, and, within each environmental category, specific elements/aspects are discussed. This paper provides a comprehensive map connecting identified levels of influence (individual, home/house, and neighborhood-level) in which subfactors are listed under each level of influence/category with the related literature list. Our review highlights that multidimensional environmental factors can affect aging adults' sleep health and eventually their physical, mental, and cognitive health and that sleep disparities exist in racial minorities in socioeconomically disadvantaged communities in which cumulative environmental stressors coexist. Based on this focused narrative review on the multidimensional sleep environments for aging adults, knowledge gaps are identified, and future research directions are suggested.

Impact of Sleep Fragmentation on Cognition and Fatigue

Sleep continuity and efficacy are essential for optimal cognitive functions. How sleep fragmentation (SF) impairs cognitive functioning, and especially cognitive fatigue (CF), remains elusive. We investigated the impact of induced SF on CF through the TloadDback task, measuring interindividual variability in working memory capacity. Sixteen participants underwent an adaptation polysomnography night and three consecutive nights, once in a SF condition induced by non-awakening auditory stimulations, once under restorative sleep (RS) condition, counterbalanced within-subject. In both conditions, participants were administered memory, vigilance, inhibition and verbal fluency testing, and for CF the TloadDback, as well as sleep questionnaires and fatigue and sleepiness visual analog scales were administered. Subjective fatigue increased and sleep architecture was altered after SF (reduced sleep efficiency, percentage of N3 and REM, number of NREM and REM phases) despite similar total sleep time. At the behavioral level, only inhibition deteriorated after SF, and CF similarly evolved in RS and SF conditions. In line with prior research, we show that SF disrupts sleep architecture and exerts a deleterious impact on subjective fatigue and inhibition. However, young healthy participants appear able to compensate for CF induced by three consecutive SF nights. Further studies should investigate SF effects in extended and/or pathological disruption settings.

The Need for Social and Environmental Determinants of Health Research to Understand and Intervene on Racial/Ethnic Disparities in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA), a sleep-disordered breathing (SDB) disorder, affects at least 25 million adults in the United States and is associated with increased risk for hypertension, diabetes, and cardiovascular disease (CVD). Racial/ethnic minorities have a disproportionate burden of OSA along with the health sequelae associated with this condition. Despite supporting evidence of racial/ethnic disparities, few studies have investigated SDB including OSA among minoritized racial/ethnic groups. In this scoping review of the literature, the authors summarize current findings related to racial/ethnic disparities in OSA, identified social and environmental determinants of health, treatment inequities, and promising evidence-based interventions and conclude with future research directions.

The Association of Ambient Air Pollution with Sleep Apnea: The Multi-Ethnic Study of Atherosclerosis

RATIONALE

Air pollution may influence sleep through airway inflammation or autonomic nervous system pathway alterations. Epidemiological studies may provide evidence of relationships between chronic air pollution exposure and sleep apnea.

OBJECTIVES

To determine whether ambient-derived pollution exposure is associated with obstructive sleep apnea and objective sleep disruption.

METHODS

We analyzed data from a sample of participants in MESA (Multi-Ethnic Study of Atherosclerosis) who participated in both the Sleep and Air studies. Mean annual and 5-year exposure levels to nitrogen dioxide (NO₂) and particulate matter ≤ 2.5 μm in aerodynamic diameter (PM_2.5) were estimated at participants' homes using spatiotemporal models based on cohort-specific monitoring. Participants completed in-home full polysomnography and 7 days of wrist actigraphy. We used multivariate models, adjusted for demographics, comorbidities, socioeconomic factors, and site, to assess whether air pollution was associated with sleep apnea (apnea-hypopnea index ≥ 15) and actigraphy-measured sleep efficiency.

RESULTS

The participants (n = 1,974) were an average age of 68 (±9) years, 46% male, 36% white, 24% Hispanic, 28% black, and 12% Asian; 48% had sleep apnea and 25% had a sleep efficiency of ≤88%. A 10 ppb annual increase in NO₂ exposure was associated with 39% greater adjusted odds of sleep apnea (95% confidence interval [CI], 1.03-1.87). A 5 μg/m³ greater annual PM_2.5 exposure was also associated with 60% greater odds of sleep apnea (95% CI, 0.98-2.62). Sleep efficiency was not associated with air pollution levels in fully adjusted models.

CONCLUSIONS

Individuals with higher annual NO₂ and PM_2.5 exposure levels had a greater odds of sleep apnea. These data suggest that in addition to individual risk factors, environmental factors also contribute to the variation of sleep disorders across groups, possibly contributing to health disparities.

Environmental Determinants of Insufficient Sleep and Sleep Disorders: Implications for Population Health

PURPOSE OF REVIEW

Sleep is important for overall health and well-being. Insufficient sleep and sleep disorders are highly prevalent among adults and children and therefore a public health burden, particularly because poor sleep is associated with adverse health outcomes. Emerging evidence has demonstrated that environmental factors at the household- and neighborhood-level can alter healthy sleep. This paper will (1) review recent literature on the environmental determinants of sleep among adults as well as children and adolescents; and (2) discuss the opportunities and challenges for advancing research on the environment and sleep.

RECENT FINDINGS

Epidemiologic research has shown that social features of environments, family, social cohesion, safety, noise, and neighborhood disorder can shape and/or impact sleep patterns; and physical features such as light, noise, traffic, pollution, and walkability can also influence sleep and is related to sleep disorders among adults and children. Prior research has mainly measured one aspect of the environment, relied on self-reported sleep, which does not correlate well with objective measures, and investigated cross-sectional associations. Although most studies are conducted among non-Hispanic white populations, there is growing evidence that indicates that minority populations are particularly vulnerable to the effects of the environment on insufficient sleep and sleep disorders.

SUMMARY

There is clear evidence that environmental factors are associated with insufficient sleep and sleep disorders. However, more research is warranted to evaluate how and which environmental factors contribute to sleep health. Interventions that target changes in the environment to promote healthy sleep should be developed, tested, and evaluated as a possible pathway for ameliorating sleep health disparities and subsequently health disparities.

Sex differences in healthy human heart rate variability: A meta-analysis

The present meta-analysis aimed to quantify current evidence on sex differences in the autonomic control of the heart, indexed by measures of heart rate variability (HRV) in healthy human subjects. An extensive search of the literature yielded 2020 titles and abstracts, of which 172 provided sufficient reporting of sex difference in HRV. Data from 63,612 participants (31,970 females) were available for analysis. Meta-analysis yielded a total of 1154 effect size estimates (k) across 50 different measures of HRV in a cumulated total of 296,247 participants. Females showed a significantly lower mean RR interval and standard deviation of RR intervals (SDNN). The power spectral density of HRV in females is characterized by significantly less total power that contains significantly greater high- (HF) and less low-frequency (LF) power. This is further reflected by a lower LF/HF ratio. Meta-regression revealed significant effects of age, respiration control and the length of recording available for analysis. Although women showed greater mean heart rate, they showed greater vagal activity indexed by HF power of HRV. Underlying mechanisms of these findings are discussed.