Relationship between ethnicity and sleep patterns in normal controls: implications for psychopathology and treatment

The Relationship between Sleep and Physical Activity by Age, Race, and Gender

Cardiometabolic diseases remain the leading cause of death in the United States. Lifestyle factors contribute the majority of risk for these diseases. Although diet and exercise have been the primary focus of research on modifiable behaviors to target for interventions to prevent cardiometabolic disease, recent evidence suggests that sleep also plays an important role. Indeed, the updated American Heart Association campaign includes sleep as one of its "Essential Eight". This review details the reciprocally reinforcing positive relationship between sleep and daytime physical activity behaviors and explores how this relationship differs based on age, gender and race. For example, interventions to improve moderate intensity physical activity may be particularly beneficial to women, older adults, and Black Americans, who are at increased risk for sleep disturbances. Communicating to Americans the importance of managing their time to meet current physical activity and sleep recommendations is a challenge given that there are so many competing behaviors consuming large amounts of time (e.g., social media, gaming), but is critical given the importance of these behaviors for cardiometabolic health.

Sleep, Health Outcomes and Body Weight (SHOW) study: a measurement burst design study on sleep and risk factors for obesity in black emerging adults in North Carolina, USA

INTRODUCTION

Black emerging adults (18-28 years) have the highest risk of short sleep duration and obesity. This increased risk may be partly explained by greater stress levels, which may result from race-related stress (racial discrimination and heightened race-related vigilance) or living in more disadvantaged home and neighbourhood environments. Insufficient sleep may also impact obesity risk via several weight-related mechanisms including energy balance, appetite and food reward, cortisol profiles and hydration status. This paper describes the rationale, design and methods for the Sleep, Health Outcomes and Body Weight (SHOW) study. This study aims to prospectively assess the effects of sleep, race-related stress and home/neighbourhood environments on weight-related mechanisms and obesity markers (body weight, waist circumference and fat mass) in 150 black emerging adults.

METHODS AND ANALYSIS

The SHOW study follows a measurement burst design that includes 3, 7-day data collection bursts (baseline, 6-month and 12-month follow-ups). Sleep is measured with three methods: sleep diary, actigraphy and polysomnography. Energy balance over 7 days is based on resting and postprandial energy expenditure measured via indirect calorimetry, physical activity via accelerometry and self-reported and ad libitum energy intake methods. Self-reported methods and blood biomarkers assess fasting and postprandial appetite profiles and a behavioural-choice task measures food reward. Cortisol awakening response and diurnal cortisol profiles over 3 days are assessed via saliva samples and chronic cortisol exposure via a hair sample. Hydration markers are assessed with 24-hour urine collection over 3 days and fasting blood biomarkers. Race-related stress is self-reported over 7 days. Home and neighbourhood environments (via the Windshield Survey) is observer assessed.

ETHICS AND DISSEMINATION

Ethics approval was granted by the University of North Carolina at Greensboro's Institutional Review Board. Study findings will be disseminated through peer-reviewed publications, presentations at scientific meetings and reports, briefs/infographics for lay and community audiences.

Developing a culturally tailored digital health intervention for insomnia in Black women

Insomnia disorder is highly prevalent among Black women. Cognitive-behavioral therapy for insomnia (CBT-I) is considered the optimal treatment, but very little efficacy research has been conducted in minority populations. Culturally tailoring intervention content may increase participant engagement and improve treatment outcomes. We culturally tailored an Internet-delivered CBT-I program (Sleep Healthy Using the Internet; SHUTi) for Black women. First, relevant stakeholders were identified. Semi-structured interviews were conducted after stakeholders completed each of the six SHUTi intervention sessions. Questions focused on improving program relatability and engagement for Black women. Key themes pertinent to peripheral, evidential, and sociocultural strategies for cultural adaptation were identified using thematic content analysis, and adaptation recommendations were developed. A total of 50 interviews, across 9 stakeholders, were conducted. Two overarching themes were identified: (i) there was limited visual African American representation, and (ii) there was a lack of diversity in the environments and lifestyles of the patient vignettes. Respondents provided peripheral, evidential, and sociocultural recommendations for program modifications, emphasizing the importance of race-concordant visual content and didactic content exploring the diverse cultural and social contexts in which insomnia occurs for Black women. As more diverse patients seek evidence-based insomnia treatment, digital health interventions must consider whether it is therapeutically important to address and tailor for cultural differences. Here, stakeholders made clear recommendations for taking cultural contexts into account to improve patient engagement with the program. Further research should work to understand the extent to which culturally tailored interventions are beneficial for health outcomes among minority populations.

Obstructive Sleep Apnea and Alzheimer's Disease Pathology: Is Sleep Architecture the Missing Key?

Impairments of the sleep architecture due to disrupted sleep in individuals with obstructive sleep apnea (OSA) may result in reduced slow wave sleep (SWS), intermittent hypoxemia, and excessive day time sleepiness- all factors that have been shown to impact Alzheimer's disease (AD) risk. In this commentary, we comment on the work by Cavuoto and colleagues in which they examine the associations between nocturnal hypoxemia or sleep disruptions (during SWS) and amyloid-β burden in individuals with OSA. We review the findings in the context of other similar studies and highlight the strengths and weaknesses of these published studies. We note the importance of examining these relationships longitudinally with a large sample size, including considering sleep health disparities, vascular components, and multiple cognitive domain tests.

Systematic review: sleep health in the US Latinx population

Sleep disturbances are a common and unmet health problem in Latinx. While Latinx report similar sleep disturbances as non-Hispanic Whites [NHW], Latinx suffer from these disturbances to a greater degree than their NHW counterparts. Sleep disturbances are associated with increased risk of chronic health conditions, which Latinx experience at high rates. Research also points to significant sleep differences within Latinx. Given that Latinx are a rapidly growing population in the United States, sleep disparities between Latinx and NHWs and sleep differences within Latinx warrant further investigation. While research on Latinx sleep is growing, the last narrative review on US Latinx sleep health was published by Loredo and colleagues in 2010. Our narrative review expands on Loredo et al.'s work, adding the literature on Latinx sleep published since 2010 (N = 70). A total of 78 peer-reviewed articles related to young to middle-aged (i.e., 18-65 years) healthy Latinx adult sleep were identified in three databases-PsycInfo, PubMed/Medline, and Web of Science. With the socioecological model as framework, this review (1) summarizes current evidence pertaining to sleep health in healthy, community dwelling, urban Latinx adults; (2) discusses measurement challenges related to investigating Latinx sleep disparities and differences; and (3) discusses potential contributors to Latinx sleep. The prevalence of short sleep duration, long sleep duration, and poor sleep quality is high among Latinx; there are differences by Latinx subgroup. Our review identifies several multi-level influences associated with poor sleep: SES, sexual minority status, racial discrimination, access to care, neighborhood environment, and shift work. N = 250/250.

A scoping review of racial/ethnic disparities in sleep

BACKGROUND

Despite remarkable achievements in ensuring health equity, racial/ethnic disparities in sleep still persist and are emerging as a major area of concern. Accumulating evidence has not yet been well characterized from a broad perspective. We conducted a scoping review of studies on sleep disparities by race/ethnicity to summarize characteristics of existing studies and identify evidence gaps.

METHODS

We searched PubMed, CINAHL, PsycINFO, and Web of Science databases for studies of racial/ethnic disparities in sleep. Studies that met inclusion criteria were retrieved and organized in a data charting form by study design, sleep measuring methods, sleep features, and racial/ethnic comparisons.

RESULTS

One hundred sixteen studies were included in this review. Most studies focused on disparities between Whites and Blacks. Disproportionately fewer studies examined disparities for Hispanic, Asian, and other racial/ethnic groups. Self-reported sleep was most frequently used. Sleep duration, overall sleep quality, and sleep disordered breathing were frequently studied, whereas other features including sleep efficiency, latency, continuity, and architecture were understudied, particularly in racial minority groups in the US. Current study findings on racial/ethnic disparities in most of sleep features is mixed and inconclusive.

CONCLUSIONS

This review identified significant evidence gaps in racial/ethnic disparities research on sleep. Our results suggest a need for more studies examining diverse sleep features using standardized and robust measuring methods for more valid comparisons of sleep health in diverse race/ethnicity groups.

Sex and race influence objective and self-report sleep and circadian measures in emerging adults independently of risk for bipolar spectrum disorder

There is a need to better understand key factors that impact sleep and circadian function for young adults of differing races and sexes. Sex and race are common factors contributing to disparities in health outcomes; however, the influence of these variables on sleep and circadian patterns for young adults are not well known. Multiple objective and self-report facets of sleep and circadian function were assessed (melatonin onset, actigraphy, and sleep diaries) in an ecological momentary assessment study of 150 emerging adults (M_age = 21.8 years; 58.7% female; 56% White, 22.7% Black, 21.3% Other ethnicity) at high or low risk for bipolar spectrum disorder (BSD). Controlling for BSD risk status, sex and race were significant predictors of objective and self-reported sleep and circadian rhythm measures. Males self-reported better sleep efficiency and exhibited later dim light melatonin onset phase than females, whereas females exhibited more actigraphy-measured sleep periods. White participants exhibited more actigraphy-measured total sleep time (TST), better sleep efficiency, and fewer sleep periods, and more self-reported TST and better sleep efficiency than Black participants. Our findings enhance the literature by utilizing robust measurement of sleep and circadian parameters to extend previous findings to a young adult sample at high or low risk for BSD.

Racial/Ethnic Differences in Sleep Quality among Older Adults: Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

Background

We assessed cross-sectional differences in sleep quality and risk factors among Asian, Black, Latino, and White participants in the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study.

Methods

KHANDLE enrolled community-dwelling adults aged ≥65 years living in northern California. Participants completed a modified Pittsburgh Sleep Quality Index to measure six sleep components and a global sleep score (scored 0-24). Covariates included age, sex, central adiposity, education, income, alcohol consumption, ever smoking, physical activity, and depression. Ordinal logistic regression was used to model sleep component scores across race/ethnic groups. Linear regression was used to assess racial/ethnic differences in global sleep score and the association between risk factors and global sleep score.

Results

1,664 participants with a mean age of 76 (SD=7) and mean global sleep score of 6 (SD=4) were analyzed. Using Latinos as reference (highest average sleep score), Blacks had an average .96 (.37, 1.54) unit higher global sleep score (worse sleep) while Asians [β: .04 (-.56, .63)] and Whites [β: .28 (-.29, .84)] did not significantly differ. Compared with Latinos, Blacks and Asians had greater odds of a worse score on the sleep duration component; Blacks and Whites had greater odds of a worse score on the sleep disturbances component; and, Whites had greater odds of a worse score on the medication component. Risk factors for poor sleep did not differ by race/ethnicity except alcohol consumption (interaction P=.04), which was associated with poor sleep in Blacks only.

Conclusions

In this cohort, racial/ethnic differences in sleep quality were common.

Are sleep patterns influenced by race/ethnicity - a marker of relative advantage or disadvantage? Evidence to date

Sleep is a fundamental necessity of life. However, sleep health and sleep disorders are not equitably distributed across racial/ethnic groups. In fact, growing research consistently demonstrates that racial/ethnic minorities are more likely to experience, for instance, shorter sleep durations, less deep sleep, inconsistent sleep timing, and lower sleep continuity in comparison to Whites. However, racial/ethnic disparities in reports of sleepiness and sleep complaints are inconsistent. Racial/ethnic groups have significant heterogeneity, yet within-group analyses are limited. Among the few published within-group analyses, there are differences in sleep between non-US-born and US-born racial/ethnic groups, but the group with the more favorable sleep profile is consistent for non-US-born Latinos compared to US-born Latinos and Whites but unclear for other racial/ethnic minority groups. These sleep health disparities are a significant public health problem that should garner support for more observational, experimental, intervention, and policy/implementation research. In this review, we 1) summarize current evidence related to racial/ethnic disparities in sleep health and within-group differences, focusing on the sleep of the following racial/ethnic minority categories that are defined by the United States Office of Management and Budget as: American Indian/Alaska Native, Asian, African American/Black, Hispanic/Latino, and Native Hawaiian/Pacific Islander; 2) discuss measurement challenges related to investigating sleep health disparities; 3) discuss potential contributors to sleep health disparities; 4) present promising interventions to address sleep health disparities; and 5) discuss future research directions on intersectionality and sleep health.

Sleep and cognitive performance of African-Americans and European-Americans before and during circadian misalignment produced by an abrupt 9-h delay in the sleep/wake schedule

We conducted two studies of circadian misalignment in non-Hispanic African and European-Americans. In the first, the sleep/wake (light/dark) schedule was advanced 9 h, similar to flying east, and in the second these schedules were delayed 9 h, similar to flying west or sleeping during the day after night work. We confirmed that the free-running circadian period is shorter in African-Americans compared to European-Americans, and found differences in the magnitude and direction of circadian rhythm phase shifts which were related to the circadian period. The sleep and cognitive performance data from the first study (published in this journal) documented the impairment in both ancestry groups due to this extreme circadian misalignment. African-Americans slept less and performed slightly worse during advanced/misaligned days than European-Americans. The current analysis is of sleep and cognitive performance from the second study. Participants were 23 African-Americans and 22 European-Americans (aged 18-44 years). Following four baseline days (8 h time in bed, based on habitual sleep), the sleep/wake schedule was delayed by 9 h for three days. Sleep was monitored using actigraphy. During the last two baseline/aligned days and the first two delayed/misaligned days, beginning 2 h after waking, cognitive performance was assessed every 3 h using the Automated Neuropsychological Assessment Metrics (ANAM) battery. Mixed model ANOVAs assessed the effects of ancestry (African-American or European-American) and condition (baseline/aligned or delayed/misaligned) on sleep and performance. There was decreased sleep and impaired cognitive performance in both ancestry groups during the two delayed/misaligned days relative to baseline/aligned days. Sleep and cognitive performance did not differ between African-Americans and European-Americans during either baseline/aligned or delayed/misaligned days. While our previous work showed that an advance in the sleep/wake schedule impaired the sleep of African-Americans more than European-Americans, delaying the sleep/wake schedule impaired the sleep and cognitive performance of African-Americans and European-Americans equally.

Advancing the sleep/wake schedule impacts the sleep of African-Americans more than European-Americans

There are differences in sleep duration between Blacks/African-Americans and Whites/European-Americans. Recently, we found differences between these ancestry groups in the circadian system, such as circadian period and the magnitude of phase shifts. Here we document the role of ancestry on sleep and cognitive performance before and after a 9-h advance in the sleep/wake schedule similar to flying east or having a large advance in sleep times due to shiftwork, both of which produce extreme circadian misalignment. Non-Hispanic African and European-Americans (N = 20 and 17 respectively, aged 21-43 years) were scheduled to four baseline days each with 8 h time in bed based on their habitual sleep schedule. This sleep/wake schedule was then advanced 9 h earlier for three days. Sleep was monitored using actigraphy. During the last two baseline/aligned days and the first two advanced/misaligned days, beginning 2 h after waking, cognitive performance was measured every 3 h using the Automated Neuropsychological Assessment Metrics (ANAM) test battery. Mixed model ANOVAs assessed the effects of ancestry (African-American or European-American) and condition (baseline/aligned or advanced/misaligned) on sleep and cognitive performance. There was decreased sleep and impaired performance in both ancestry groups during the advanced/misaligned days compared to the baseline/aligned days. In addition, African-Americans obtained less sleep than European-Americans, especially on the first two days of circadian misalignment. Cognitive performance did not differ between African-Americans and European-Americans during baseline days. During the two advanced/misaligned days, however, African-Americans tended to perform slightly worse compared to European-Americans, particularly at times corresponding to the end of the baseline sleep episodes. Advancing the sleep/wake schedule, creating extreme circadian misalignment, had a greater impact on the sleep of African-Americans than European-Americans. Ancestry differences in sleep appear to be exacerbated when the sleep/wake schedule is advanced, which may have implications for individuals undertaking shiftwork and transmeridian travel.

Determinants of racial/ethnic disparities in disordered sleep and obesity

Racial/ethnic minorities experience a disproportionate risk of both suboptimal sleep and obesity, and the relationship between sleep and obesity may differ by race/ethnicity for modifiable and non-modifiable reasons. Because many people of color have historically lived and continue to largely live in disadvantaged, obesogenic physical and social environments, these greater adverse exposures likely negatively affect sleep, resulting in physiological dysregulation. Physiological dysregulation may, in turn, lead to increased obesity risk and subsequent health consequences, which are likely more influential than potential genetic differences in race, a social construct. The purpose of this article is to describe potential environmental, genetic, and epigenetic determinants of racial/ethnic differences in the sleep-obesity relationship and to review current epidemiological findings regarding either racial/ethnic minority specific estimates of the association or disparities in the relationship. Using the socioecological framework as a conceptual model, I describe sleep and obesity as socially patterned and embedded in modifiable physical and social contexts with common causes that are influenced by upstream social conditions. I also provide examples of sleep and obesity-related studies that correspond with the downstream, intermediate, and upstream factors that likely contribute to commonly observed racial/ethnic disparities in the sleep-obesity relationship. The review concludes with broad recommendations for (1) advancing research methodology for epidemiological studies of disparities in the link between sleep and obesity, (2) future research topics, as well as (3) several broad policies and structures needed to address racial/ethnic disparities in sleep health and obesity.

Place of Birth and Sleep Duration: Analysis of the National Health Interview Survey (NHIS)

While sleep disturbance has been related to a number of negative health outcomes, few studies have examined the relationship between place of birth and sleep duration among individuals living in the US. Data for 416,152 adult participants in the 2000-2013 National Health Interview Survey (NHIS), who provided self-reported hours of sleep and place of birth were examined. Associations were explored between healthy sleep (7-8 h), referenced to unhealthy sleep (<7 or >8 h), and place of birth using multivariate logistic regression analysis. The mean age of the sample was 47.4 ± 0.03 years; 56% were female. Of the respondents, 61.5% reported experiencing healthy sleep, 81.5% reported being born in the US and 18.5% were foreign-born adults. Descriptive statistics revealed that Indian Subcontinent-born respondents (71.7%) were more likely to report healthy sleep compared to US-born respondents (OR = 1.53, 95% CI = 1.37-1.71, p < 0.001), whereas African-born respondents (43.5%) were least likely to report healthy sleep (OR = 0.78, 95% CI = 0.70-0.87, p < 0.001). These findings suggest that place of birth should be considered in the assessment of risk factors for unhealthy sleep.

Sleep disparity, race/ethnicity, and socioeconomic position

Sleep represents a set of biological functions necessary for the maintenance of life. Performing these functions, though, requires that an individual engage in behaviors, which are affected by social and environmental factors. Race/ethnicity and socioeconomic position represent categories of factors that likely play a role in the experience of sleep in the community. Previous studies have suggested that racial/ethnic minorities and the socioeconomically disadvantaged may be more likely to experience sleep patterns that are associated with adverse health outcomes. It is possible that disparities in sleep represent a pathway by which larger disparities in health emerge. This review (1) contextualizes the concept of race/ethnicity in biomedical research, (2) summarizes previous studies that describe patterns of sleep attainment across race/ethnicity groups, (3) discusses several pathways by which race/ethnicity may be associated with sleep, (4) introduces the potential role of socioeconomic position in the patterning of sleep, and (5) proposes future research directions to address this issue.

Differential changes and interactions of autonomic functioning and sleep architecture before and after 50 years of age

We hypothesize that the time when age-related changes in autonomic functioning and in sleep structure occur are different and that autonomic functioning modulates sleep architecture differently before and after 50 years of age. Sixty-eight healthy subjects (aged 20 to 79 years old, 49 of them women) were enrolled. Correlation analysis revealed that wake after sleep onset, the absolute and relative value of stage 1 (S1; S1%), and relative value of stage 2 (S2) were positively correlated with age; however, sleep efficiency, stage 3 (S3), S3%, and rapid-eye-movement latency (REML) were negatively correlated with age. Significant degenerations of sleep during normal aging were occurred after 50 years of age; however, significant declines of autonomic activity were showed before 50 years of age. Before 50 years of age, vagal function during sleep was negatively correlated with arousal index; however, after 50 years of age, it was positively correlated with S1 and S1%. In addition, sympathetic activity during wake stage was positively related to S2% only after 50 years of age. Our results imply that the age-related changes in autonomic functioning decline promptly as individuals leave the younger part of their adult life span and that age-related changes in sleep slowly develop as individuals enter the older part of their adult life span. Furthermore, while various aspects of sleep architecture are modulated by both the sympathetic and vagal nervous systems during adult life span, the sleep quality is mainly correlated with the sympathetic division after 50 years of age.

Short- and Long-Term Sleep Stability in Insomniacs and Healthy Controls

STUDY OBJECTIVES

Assess the short- and long-term stability of sleep duration in patients with insomnia and normal-sleeping controls.

DESIGN

Observational short-term and prospective studies.

SETTING

Sleep laboratory.

PARTICIPANTS

Patients with insomnia (n = 150) and controls (n = 151) were recruited from the local community or sleep disorders clinic. A subsample of 95 men from the Penn State Adult Cohort (PSAC) were followed up 2.6 y after their initial visit.

MEASUREMENTS

Participants underwent a physical examination and 8-h polysomnography (PSG) recording for 3 consecutive nights (controls and insomniacs), or 2 single nights separated by several years (PSAC). Intraclass correlation coefficients (ICCs) assessed the stability of the variables total sleep time (TST), sleep onset latency (SOL), and wake after sleep onset (WASO). We also examined persistence of the first-night classification of "short" versus "normal" sleep duration on subsequent nights.

RESULTS

Stability of TST, SOL, and WASO based on 1 night were slight to moderate in both patients with insomnia (ICC = 0.37-0.57) and controls (ICC = 0.39-0.59), and became substantial to almost perfect when based on the average of 3 nights (ICC = 0.64-0.81). We observed similar degrees of stability for TST and WASO in the longitudinal sample, with moderate stability based on a single night and substantial stability based on both nights. In examining the persistence of "short" and "normal" sleep duration, 71.4% (controls), 74.7% (patients with insomnia), and 72.6% (longitudinal sample) of participants retained their first-night classifications over subsequent nights.

CONCLUSIONS

Sleep duration variables, particularly total sleep time based on 3 consecutive nights in both patients with insomnia and controls or two single-night recordings separated by several years, are stable and reflect a person's habitual sleep. Furthermore, a single night in the laboratory may be useful for reliably classifying one's sleep duration.

Has adult sleep duration declined over the last 50+ years?

The common assumption that population sleep duration has declined in the past few decades has not been supported by recent reviews, which have been limited to self-reported data. The aim of this review was to assess whether there has been a reduction in objectively recorded sleep duration over the last 50+ years. The literature was searched for studies published from 1960 to 2013, which assessed objective sleep duration (total sleep time (TST)) in healthy normal-sleeping adults. The search found 168 studies that met inclusion criteria, with 257 data points representing 6052 individuals ages 18-88 y. Data were assessed by comparing the regression lines of age vs. TST in studies conducted between 1960 and 1989 vs. 1990-2013. Weighted regression analyses assessed the association of year of study with age-adjusted TST across all data points. Regression analyses also assessed the association of year of study with TST separately for 10-y age categories (e.g., ages 18-27 y), and separately for polysomnographic and actigraphic data, and for studies involving a fixed sleep schedule and participants' customary sleep schedules. Analyses revealed no significant association of sleep duration with study year. The results are consistent with recent reviews of subjective data, which have challenged the notion of a modern epidemic of insufficient sleep.

Physical activities and sleep-related symptoms in 4 major racial/ethnic groups of midlife women

The purpose of this study was to determine racial/ethnic differences in midlife women's sleep-related symptoms, relationships between their physical activity and sleep-related symptoms, and specific factors associated with their sleep-related symptoms in each racial/ethnic group. This was a secondary analysis of the data from 542 midlife women in the United States. The data were analyzed using descriptive statistics, χ tests, analysis of variance, hierarchical multiple linear regression analyses, and logistic regression analyses. The findings indicated that physical activities could improve midlife women's sleep-related symptoms, but the types of physical activities and racially/ethnically different factors associated with sleep-related symptoms need to be considered.

Racial disparities in short sleep duration by occupation and industry

Short sleep duration, which is associated with increased morbidity and mortality, has been shown to vary by occupation and industry, but few studies have investigated differences between black and white populations. By using data from a nationally representative sample of US adult short sleepers (n = 41,088) in the National Health Interview Survey in 2004-2011, we estimated prevalence ratios for short sleep duration in blacks compared with whites for each of 8 industry categories by using adjusted Poisson regression models with robust variance. Participants' mean age was 47 years; 50% were women and 13% were black. Blacks were more likely to report short sleep duration than whites (37% vs. 28%), and the black-white disparity was widest among those who held professional occupations. Adjusted short sleep duration was more prevalent in blacks than whites in the following industry categories: finance/information/real estate (prevalence ratio (PR) = 1.44, 95% confidence interval (CI): 1.30, 1.59); professional/administrative/management (PR = 1.30, 95% CI: 1.18, 1.44); educational services (PR = 1.39, 95% CI: 1.25, 1.54); public administration/arts/other services (PR = 1.30, 95% CI: 1.21, 1.41); health care/social assistance (PR = 1.23, 95% CI: 1.14, 1.32); and manufacturing/construction (PR = 1.14, 95% CI: 1.07, 1.20). Short sleep generally increased with increasing professional responsibility within a given industry among blacks but decreased with increasing professional roles among whites. Our results suggest the need for further investigation of racial/ethnic differences in the work-sleep relationship.

Insomnia in alcohol dependence: predictors of symptoms in a sample of veterans referred from primary care

OBJECTIVE

Patients with alcohol dependence presenting for treatment may have multiple associated co-morbid conditions and limited social supports, which complicate treatment. Each of these factors has been independently associated with complaints of insomnia. In this preliminary study, we investigated the relations between insomnia complaints and socio-demographic factors and psychiatric co-morbidity in treatment-seeking patients with alcohol dependence.

METHOD

We conducted a retrospective chart review on 84 consecutive patients referred to the Behavioral Health Laboratory of the Philadelphia Veterans Affairs Medical Center for evaluation of psychiatric and substance use disorders. Patients met DSM-IV diagnostic criteria for alcohol dependence and completed a series of self-assessments of sleep. Univariate and multivariable analyses were used to examine the relations amongst the variables of interest.

RESULTS

In multivariable models, Sleep Latency was significantly greater in individuals without partners (p = .01), those with psychiatric disorders (p = .03) and smokers (p = .01), with a non-significant trend for those with past-year suicidal ideation. No significant predictor of Wake Time After Sleep Onset was seen. Poor Sleep Quality was predicted by younger age (OR = .93 [.88, .98], p = .004) and the presence of a psychiatric disorder (OR = 20.80 [4, 102], p = .0002), with a non-significant trend for suicidal ideation.

CONCLUSIONS

Insomnia symptoms in treatment-seeking alcohol dependent patients should prompt consideration of the individuals' psychiatric and psychosocial features.

Comparisons of the sleep quality, daytime sleepiness, and sleep cognitions of Caucasian Australians and Zimbabwean and Ghanaian black immigrants

Studying sleep differences across different ethnic groups is not only important for our understanding of sleep but may lead to the development of new, culturally appropriate interventions. Perceptions of sleep quality, daytime sleepiness, and sleep cognitions (beliefs and attitudes) were investigated in a community sample of Caucasian Australians and Black immigrants currently resident in Australia from Zimbabwe (Black Zimbabwean) and Ghana (Black Ghanaian). A sample of a total of 176 participants including Caucasian Australian ( n = 58), Black Zimbabwean ( n = 59), and Black Ghanaian ( n = 59), aged between 18 and 60 years was surveyed. Groups were matched on age and gender, with a strong predominance of professional occupations in all groups in the final sample and no significant socio-economic status differences between groups. Participants completed the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Dysfunctional Beliefs and Attitudes about Sleep, and the Short Form-36 Health Survey. After matching participants on age, gender, and socio-economic status, no statistically significant group differences were found on sleep quality, daytime sleepiness, and physical health. However, significant group differences were found on beliefs and attitudes about sleep with Black Zimbabwean and Black Ghanaian participants, attributing sleep difficulties more to physical than psychological phenomena compared to Caucasian Australian participants.

Short-term stability of sleep and heart rate variability in good sleepers and patients with insomnia: for some measures, one night is enough

STUDY OBJECTIVES

Quantify the short-term stability of multiple indices of sleep and nocturnal physiology in good sleeper controls and primary insomnia patients.

DESIGN

Intra-class correlation coefficients (ICC) were used to quantify the short-term stability of study outcomes.

SETTING

Sleep laboratory.

PARTICIPANTS

Fifty-four adults with primary insomnia (PI) and 22 good sleeper controls (GSC).

MEASUREMENTS

Visually scored sleep outcomes included indices of sleep duration, continuity, and architecture. Quantitative EEG outcomes included power in the delta, theta, alpha, sigma, and beta bands during NREM sleep. Power spectral analysis was used to estimate high-frequency heart rate variability (HRV) and the ratio of low- to high-frequency HRV power during NREM and REM sleep.

RESULTS

With the exception of percent stage 3+4 sleep; visually scored sleep outcomes did not exhibit short-term stability across study nights. Most QEEG outcomes demonstrated short-term stability in both groups. Although power in the beta band was stable in the PI group (ICC = 0.75), it tended to be less stable in GSCs (ICC = 0.55). Both measures of cardiac autonomic tone exhibited short-term stability in GSCs and PIs during NREM and REM sleep.

CONCLUSIONS

Most QEEG bandwidths and HRV during sleep show high short-term stability in good sleepers and patients with insomnia alike. One night of data is, thus, sufficient to derive reliable estimates of these outcomes in studies focused on group differences or correlates of QEEG and/or HRV. In contrast, one night of data is unlikely to generate reliable estimates of PSG-assessed sleep duration, continuity or architecture, with the exception of slow wave sleep.

Sociodemographic and cultural determinants of sleep deficiency: implications for cardiometabolic disease risk

Sleep is a biological imperative associated with cardiometabolic disease risk. As such, a thorough discussion of the sociocultural and demographic determinants of sleep is warranted, if not overdue. This paper begins with a brief review of the laboratory and epidemiologic evidence linking sleep deficiency, which includes insufficient sleep and poor sleep quality, with increased risk of chronic cardiometabolic diseases such as obesity, diabetes and hypertension. Identification of the determinants of sleep deficiency is the critical next step to understanding the role sleep plays in human variation in health and disease. Therefore, the majority of this paper describes the different biopsychosocial determinants of sleep, including age, gender, psychosocial factors (depression, stress and loneliness), socioeconomic position and race/ethnicity. In addition, because sleep duration is partly determined by behavior, it will be shaped by cultural values, beliefs and practices. Therefore, possible cultural differences that may impact sleep are discussed. If certain cultural, ethnic or social groups are more likely to experience sleep deficiency, then these differences in sleep could increase their risk of cardiometabolic diseases. Furthermore, if the mechanisms underlying the increased risk of sleep deficiency in certain populations can be identified, interventions could be developed to target these mechanisms, reduce sleep differences and potentially reduce cardiometabolic disease risk.

Comparison of symptoms in African-American, Asian-American, Mexican-American and Non-Hispanic White patients with major depressive disorder

The study compared depressive and associated psychopathological symptoms in 17 African-American, 19 Asian-American, 22 Mexican-American and 41 Non-Hispanic White patients with unipolar major depressive disorder. Overall, severity of depression was comparable among the groups both on clinician-rated and subject-rated measures. However, ethnic-minority groups were more likely to experience diurnal variation of mood, with worsening in the evening. Furthermore, Asian-Americans and Mexican-Americans reported greater severity of anxiety and somatic symptoms. The findings suggest that clinicians should be aware of potential differences in symptom presentation when assessing and treating depressed patients from different ethnic groups.

Validation of the three-factor model of the PSQI in a large sample of chronic fatigue syndrome (CFS) patients

OBJECTIVE

To evaluate whether a 3-factor model of the Pittsburgh Sleep Quality Index (PSQI) scale would fit the constellation of sleep disturbances in patients with a diagnosis of chronic fatigue syndrome (CFS).

METHODS

Consecutive CFS patients filled out the PSQI. Scores from this self-report questionnaire were examined with exploratory and confirmatory factor analysis (CFA).

RESULTS

413 CFS patients were included for analysis in this study. CFA showed that the 7 PSQI component scores clustered into the 3 factors reported by Cole et al. (2006), i.e. Sleep Efficiency, Perceived Sleep Quality and Daily Disturbances. In contrast with the single-factor and all 2-factor models, all factor loadings were significant, and all goodness-of-fit values were acceptable.

CONCLUSION

In CFS, the PSQI operates as a 3-factor scoring model as initially seen in healthy and depressed older adults. The separation into 3 discrete factors suggests the limited usefulness of the global PSQI as a single factor for the assessment of subjective sleep quality, as also evidenced by a low Cronbach's alpha (0.64) in this patient sample.

The association of race/ethnicity with objectively measured sleep characteristics in older men

This study examined the association between race/ethnicity and objectively measured sleep characteristics in a large sample of older men. Black men had significantly shorter total sleep time (6.1 hr vs. 6.4 hr), longer sleep latency (28.7 min vs. 21.9 min), lower sleep efficiency (80.6% vs. 83.4%), and less slow-wave sleep (4.9% vs. 8.8%) than White men, even after controlling for social status, comorbidities, body mass index, and sleep-disordered breathing. Hispanic men slept longer (6.7 hr) at night than Black (6.1 hr) and Asian American men (6.1 hr). This study supports significant variations in sleep characteristics in older men by race/ethnicity.

Sleep Disturbances in Pediatric Depression

Depressive illness beginning early in life can have serious developmental and functional consequences. Therefore, understanding its etiology and pathophysiology during this developmental stage is critical for developing effective prevention and intervention strategies. There is considerable evidence of sleep alterations in adult major depressive disorder. However, studies in children and adolescents have not found consistent changes in sleep architecture paralleling adult depression. This review article summarizes sleep polysomnography research in early-onset depression, highlighting the factors associated with variable findings across studies. In addition, potential avenues for future research will be suggested in order to develop more comprehensive theoretical models and interventions for pediatric depression.

Sleep health in U.S. Hispanic population

The importance of sleep on health has only been recently recognized, and the general public and the medical community are not yet fully knowledgeable about this issue. The great majority of sleep research has been performed in whites of European descent and to a lesser extent in African Americans, making generalization of the findings to other ethnic and racial groups difficult. Very little sleep research has been done in U.S. Hispanics. However, based on the available literature and the high prevalence of risk factors in Hispanics, such as obesity, diabetes, living in the inner city, and use of alcohol, the prevalence of such important sleep disorders such as obstructive sleep apnea and sleep habits such as poor sleep hygiene are suspected to be high. There is also some evidence that acculturation to the U.S. life style may lead to worse sleep habits in Hispanics, including fewer hours of sleep. Two current large NIH sponsored studies of sleep in U.S. Hispanics promise to significantly add to the literature on various sleep disorders such as sleep disordered breathing, insomnia, restless legs syndrome, periodic limb movement disorder, and sleep habits such as short sleep duration and sleep hygiene.

Meditation acutely improves psychomotor vigilance, and may decrease sleep need

Background

A number of benefits from meditation have been claimed by those who practice various traditions, but few have been well tested in scientifically controlled studies. Among these claims are improved performance and decreased sleep need. Therefore, in these studies we assess whether meditation leads to an immediate performance improvement on a well validated psychomotor vigilance task (PVT), and second, whether longer bouts of meditation may alter sleep need.

Methods

The primary study assessed PVT reaction times before and after 40 minute periods of mediation, nap, or a control activity using a within subject cross-over design.

This study utilized novice meditators who were current university students (n = 10). Novice meditators completed 40 minutes of meditation, nap, or control activities on six different days (two separate days for each condition), plus one night of total sleep deprivation on a different night, followed by 40 minutes of meditation.

A second study examined sleep times in long term experienced meditators (n = 7) vs. non-meditators (n = 23). Experienced meditators and controls were age and sex matched and living in the Delhi region of India at the time of the study. Both groups continued their normal activities while monitoring their sleep and meditation times.

Results

Novice meditators were tested on the PVT before each activity, 10 minutes after each activity and one hour later. All ten novice meditators improved their PVT reaction times immediately following periods of meditation, and all but one got worse immediately following naps. Sleep deprivation produced a slower baseline reaction time (RT) on the PVT that still improved significantly following a period of meditation. In experiments with long-term experienced meditators, sleep duration was measured using both sleep journals and actigraphy. Sleep duration in these subjects was lower than control non-meditators and general population norms, with no apparent decrements in PVT scores.

Conclusions

These results suggest that meditation provides at least a short-term performance improvement even in novice meditators. In long term meditators, multiple hours spent in meditation are associated with a significant decrease in total sleep time when compared with age and sex matched controls who did not meditate. Whether meditation can actually replace a portion of sleep or pay-off sleep debt is under further investigation.

Racial differences in the human endogenous circadian period

The length of the endogenous period of the human circadian clock (tau) is slightly greater than 24 hours. There are individual differences in tau, which influence the phase angle of entrainment to the light/dark (LD) cycle, and in doing so contribute to morningness-eveningness. We have recently reported that tau measured in subjects living on an ultradian LD cycle averaged 24.2 hours, and is similar to tau measured using different experimental methods. Here we report racial differences in tau. Subjects lived on an ultradian LD cycle (1.5 hours sleep, 2.5 hours wake) for 3 days. Circadian phase assessments were conducted before and after the ultradian days to determine the change in circadian phase, which was attributed to tau. African American subjects had a significantly shorter tau than subjects of other races. We also tested for racial differences in our previous circadian phase advancing and phase delaying studies. In the phase advancing study, subjects underwent 4 days of a gradually advancing sleep schedule combined with a bright light pulse upon awakening each morning. In the phase delaying study, subjects underwent 4 days of a gradually delaying sleep schedule combined with evening light pulses before bedtime. African American subjects had larger phase advances and smaller phase delays, relative to Caucasian subjects. The racial differences in tau and circadian phase shifting have important implications for understanding normal phase differences between individuals, for developing solutions to the problems of jet lag and shift work, and for the diagnosis and treatment of circadian rhythm based sleep disorders such as advanced and delayed sleep phase disorder.

Ethnic differences in electroencephalographic sleep patterns in adolescents

The purpose of the study was to evaluate ethnic differences in polysomnography measures in adolescents. Ninety-six volunteers from four ethnic groups (13 African-American, 18 Asian-American, 19 Mexican-American, and 46 Non-Hispanic White) were recruited. The subjects were in good physical and psychological health, and were asymptomatic with respect to sleep/wake complaints or sleep disorders. Polysomnography measures were collected on three consecutive nights. African-Americans manifested lower sleep efficiency, spent proportionately more time in stage 2 sleep, and had less stage 4 sleep compared to the other ethnic groups. In contrast to this, Mexican-Americans had more rapid eye movement (REM) sleep than their counterparts. The observed sleep patterns in the different ethnic groups persisted after controlling for specific demographic, clinical and psychosocial variables that are known to influence sleep measures. Gender had a differential effect on sleep patterns in the various ethnic groups. For instance, differences in non-REM sleep were more evident in African-American males, whereas increased REM sleep was most notable in Mexican-American females. At present, the clinical implications of the observed cross-ethnic differences in sleep physiology among adolescents are not clear. In previous studies, reduced sleep efficiency and stage 4 sleep, as well as increased REM sleep, were associated with psychopathology. It is not known whether the traditionally described sleep profiles, based largely on Non-Hispanic White populations, will generalize to other racial or ethnic groups. In addition to a systematic investigation of this issue, future research should attempt to identify the underlying causes for cross-ethnic variations in sleep physiology.

Sleep duration among black and white Americans: results of the National Health Interview Survey

INTRODUCTION

Epidemiologic studies have shown the importance of habitual sleep duration as an index of health and mortality risks. However, little has been done to ascertain ethnic differences in sleep duration in a national sample. This study compares sleep duration in a sample of black and white participants in the National Health Interview Survey (NHIS).

METHOD

Data were collected from 29,818 Americans (age range 18-85 years) who participated in the 2005 NHIS. The NHIS is a cross-sectional household interview survey that uses a multistage area probability design, thus permitting representative sampling of U.S. households. During face-to-face interviews conducted by trained interviewers from the U.S. Census Bureau, respondents provided demographic data and information about physician-diagnosed chronic conditions, estimated habitual sleep duration and functional capacity, and rated their mood.

RESULTS

Fisher's exact test results indicated that blacks were less likely than whites to report sleeping 7 hours (23% vs. 30%; chi2 = 94, p < 0.0001). Blacks were more likely to experience both short sleep (< or = 5 hours) (12% vs. 8%, chi2 = 44, p < 0.0001) and long sleep (> or = 9 hours) (11% vs. 9%, chi2 = 23, p < 0.0001). Logistic regression analysis, adjusting for differences in sociodemographic factors, depression, functional capacity and medical illnesses, demonstrated that black ethnicity was a significant predictor of extreme sleep duration (Wald = 46, p < 0.0001; OR = 1.35, 95% CI: 1.24-1.47).

DISCUSSION

Independent of several sociodemographic and medical factors, blacks had more prevalent short and long sleep durations, suggesting greater variation in habitual sleep time. Therefore, blacks might be at increased risks of developing medical conditions associated with short and long sleep.

Influence of race and socioeconomic status on sleep: Pittsburgh SleepSCORE project

OBJECTIVE

To examine the independent and interactive effects of race and socioeconomic status (SES) on objective indices and self-reports of sleep.

METHODS

The sleep of 187 adults (41% black; mean age = 59.5 +/- 7.2 years) was examined. Nine nights of actigraphy and two nights of inhome polysomnography (PSG) were used to assess average sleep duration, continuity, and architecture; self-report was used to assess sleep quality. Psychosocial factors, health behaviors, and environmental factors were also measured.

RESULTS

Blacks had shorter sleep duration and lower sleep efficiency, as measured by actigraphy and PSG, and they spent less time proportionately in Stage 3-4 sleep, compared with others (p < .01). Lower SES was associated with longer actigraphy-measured latency, more wake after sleep onset as measured by PSG, and poorer sleep quality on the Pittsburgh Sleep Quality Index (p < .05).

CONCLUSIONS

Blacks and perhaps individuals in lower SES groups may be at risk for sleep disturbances and associated health consequences.

Racial differences in self-reports of sleep duration in a population-based study

STUDY OBJECTIVES

Racial and ethnic differences in sleep duration are not well understood. Research shows that short (< or =6 hours) and long (> or =9 hours) sleepers have higher mortality risks than mid-range sleepers. We investigated whether sleep duration varies by racial and ethnic characteristics and if some of these associations may be explained by residential context.

DESIGN

Cross-sectional National Health Interview Survey.

SETTING

Non-institutionalized adults living in the United States in 1990.

PARTICIPANTS

32,749 people aged 18 years or older.

MEASUREMENT AND RESULTS

We estimate a multinomial logistic regression that predicts short, mid-range, and long sleep duration; including covariates for race/ethnicity, among other demographic, health, and neighborhood characteristics. Black respondents had an increased risk of being short and long sleepers (OR=1.41, 95% CI=1.27-1.57 and OR=1.62, 95% CI=1.40-1.88, respectively) relative to white respondents. Hispanics (excluding Mexican Americans) and non-Hispanic "Others" were also associated with increased risk of short sleeping (OR=1.26, 95% CI= 1.07-1.49 and OR=1.35, 95% CI= 1.11-1.64, respectively). Living in an inner city was associated with increased risk of short sleeping and reduced risk of long sleeping, compared to non-urban areas. Some of the higher risk of short sleeping among blacks can be explained by higher prevalence of blacks living in the inner city.

CONCLUSIONS

Blacks and other racial minorities are more likely to have sleep durations that are associated with increased mortality. The results are consistent with the hypothesis that unhealthy sleep patterns among minorities may contribute to health differentials.

Ethnicity as a variable in mental health research: a systematic review of articles published 1990-2004

The objective of the study was to investigate how the ethnic variable has been used in mental health research, in theory, in measurement and classification criteria. Journal articles published 1990-2004 that address original research on psychopathology, treatment and mental health services and with "ethnic" or "ethnicity" in their title or abstract were selected. The papers were examined for their theoretical definition of ethnicity, how the ethnic data were collected and the criteria used to identify ethnic groups. The use of comparison groups and country of the studies were recorded. A total of 421 papers were identified. An explicit theoretical definition was found in 33 (7.8%) papers. Data collection procedure was mentioned in 248 (58.9%) and 104 (24.7%) papers described how data was converted into ethnic groups. The operationalizations of ethnicity have remained almost unchanged during the 15-year review period. Generally, the ethnic variable was incompletely reported. Confusion regarding which individual or social characteristics ethnicity refers to makes the research findings of limited value in clinical settings, and may continue to create misunderstanding about the effect of ethnicity in clinical contexts.

Trait interindividual differences in the sleep physiology of healthy young adults

Despite decades of sleep research by means of polysomnography (PSG), systematic interindividual differences in PSG-assessed sleep parameters have been scarcely investigated. The present study is the first to quantify interindividual variability in standard PSG-assessed variables of sleep structure in terms of stability and robustness as well as magnitude. Twenty-one carefully screened healthy young adults were studied continuously in a strictly controlled laboratory environment, where their PSGs were recorded for eight nights interspersed with three separate 36 h sleep deprivation periods. All PSG records were scored blind to subject and condition, using conventional criteria, and delta power in the non-REM sleep EEG was computed for four electrode derivations. Interindividual differences in sleep variables were examined for stability and robustness, respectively, by comparing results across equivalent nights (e.g. baseline nights) and across experimentally differentiated nights (baseline nights versus recovery nights following sleep deprivation). Among 18 sleep variables analyzed, all except slow-wave sleep (SWS) latency were found to exhibit significantly stable and robust--i.e. trait-like--interindividual differences. This was quantified by means of intraclass correlation coefficients (ICCs), which ranged from 36% to 89% across physiologic variables, and were highest for SWS (73%) and delta power in the non-REM sleep EEG (78-89%). The magnitude of the trait interindividual differences was considerable, consistently exceeding the magnitude of the group-average effect on sleep structure of 36 h total sleep deprivation. Notably, for non-REM delta power--a putative marker of sleep homeostasis--the interindividual differences were from 9.9 to 12.8 times greater than the group-average increase following sleep deprivation relative to baseline. Physiologic sleep variables did not vary among subjects in a completely independent manner--61.1% of their combined variance clustered in three trait dimensions, which appeared to represent sleep duration, sleep intensity, and sleep discontinuity. Any independent functional significance of these sleep physiologic phenotypes remains to be determined.

Ethnic difference in periodic limb movements in children

BACKGROUND

Epidemiological studies have suggested that ethnicity is a risk factor for sleep-disordered breathing (SDB) and that African-American children are three times more likely than Caucasian children to have SDB. Ethnic differences in sleep architecture and other routinely assessed sleep parameters have not been critically assessed, thus the aim of this study was to compare sleep characteristics in African-American and Caucasian children.

METHODS

A total of 41,363 sleep questionnaires were mailed to parents of children aged 5-7 years in Jefferson County, KY. Parents of snoring and non-snoring children were invited to have their child undergo overnight polysomnography.

RESULTS

Complete questionnaires were returned by 9872 families (23% response rate). Of these, 689 agreed to undergo polysomnography, and 542 complete polysomnograms were obtained (5.7% of questionnaire respondents). There were 391 Caucasian and 151 African-American children with a mean age of 6.7+/-0.5 years who underwent overnight polysomnographic evaluation. No differences between groups were observed for sleep latency, total sleep time, sleep efficiency, or rapid eye movement (REM) latency. African-American children had slightly increased stage 3 sleep (6.0+/-2.8% vs. 5.4+/-2.8%; p=0.01), although the total proportion of slow wave sleep was similar. Higher respiratory arousal index (3.6+/-6.5/h vs. 1.4+/-2.7/h; p<0.001) and total arousal index (11.5+/-5.2/h vs. 9.8+/-4.8/h; p<0.001) emerged in African-American children, who were more likely to have mild SDB (AHI>1:34% in African-American vs. 24% in Caucasian; p=0.017) and SDB (AHI>5: 22.5% vs. 7%; p<0.001). However, Caucasian children were more likely to have periodic leg movements during sleep (PLMS; 16.5% vs. 7% in AA; p=0.004). The odds ratio for a Caucasian child to have PLMS was 2.6 (95% confidence interval (CI) 1.3-5.3; p=0.006). Furthermore, in the absence of SDB, the odds ratio for a Caucasian child to have PLMS was 9.5 (95% CI: 2.2-39.9; p=0.002).

CONCLUSIONS

African-American and Caucasian children have similar sleep architecture. African-American children are more likely to display respiratory disturbances during sleep, while PLMS are significantly more prevalent among Caucasian children.

The sleep of African Americans: a comparative review

Researchers have not thoroughly assessed the sleep of African Americans (AAs) despite the recent increased attention to ethnic research. This article reviews the sleep and epidemiological literatures to assess AA sleep. Although the limited data were sometimes inconsistent, they suggest that AAs sleep worse than Caucasian Americans. AAs take longer to fall asleep, report poorer sleep quality, have more light and less deep sleep, and nap more often and longer. AAs have a higher prevalence of sleep-disordered breathing and exhibit more risk factors for poor sleep. These differences are concentrated in young- and middle-age adults. There are no sleep disorders treatment data for AAs. These data support further research into ethnic differences in both normal and disturbed sleep.

Ethnicity and obstructive sleep apnoea

There is a scarcity of adult prevalence studies of OSA outside the Caucasian populations of North America, Europe and Australia, and comparisons have been complicated by methodological differences in sleep study settings, respiratory events definition, measured risk factors and clinical outcomes, and the lack of objective parameters for the measurement of ethnicity itself. Comparing studies with the same methodological design and respiratory events definition, recent large-scale prevalence studies from Hong Kong, Korea and India show similar OSA rates to populations of mainly Caucasian composition. OSA is a very complex disorder determined by several phenotypes such as obesity, craniofacial structure and abnormalities in neuromuscular and ventilatory control. Genetics may partially explain some of the ethnic clustering of these phenotypes, modulated by cultural and environmental factors. The exact contribution of these component phenotypes to overall OSA risk will be determined by their varying prevalence and relative risk conferred across ethnic groups. For lesser degrees of obesity, Asians are at risk for a more severe degree of illness compared with Caucasians. Inter-ethnic studies suggests that African-American ethnicity may also be a significant risk factor for OSA. The increased prevalences of OSA among American Indians and Hispanic adults, and increased severity among Pacific Islanders and Maoris, were mainly explained by increased obesity parameters. Most cephalometric studies have largely been conducted without specific regard to ethnicity and comparisons of findings across studies have been mainly limited by differences in sampling methods and the varying selection and definition of measured cephalometric variables. The limited number of studies with inter-ethnic comparative data suggest cephalometric variables and their degree of contribution to OSA vary across ethnic groups.

An assessment of sleep architecture as a function of degree of handedness in college women using a home sleep monitor

The present study examined sleep architecture as a function of handedness in a population of undergraduate college women using a home sleep monitor. Compared to strongly handed individuals, participants with a tendency toward mixed-handedness had a shorter sleep latency and spent a greater percentage of their sleep period asleep and less awake. Increasing mixed-handedness was also associated with increased NREM; strong-handedness was associated with increased REM. Results are placed in a neurophysiological framework wherein corpus callosum mediated differences in interhemispheric interaction during Wake, REM, and NREM on the one hand, and individual differences in corpus callosum morphology and hemispheric communication as a function of handedness on the other, interact to result in handedness differences in sleep architecture.

Sleep architecture in normal Caucasian and Hispanic children aged 6-11 years recorded during unattended home polysomnography: experience from the Tucson Children's Assessment of Sleep Apnea Study (TuCASA)

OBJECTIVE

To obtain normative sleep architecture data from unattended home polysomnography in Caucasian and Hispanic children aged 6-11 years.

DESIGN AND SUBJECTS

Unattended home polysomnography was performed on a single night in Caucasian and Hispanic children aged 6-11 years as part of the Tucson Children's Assessment of Sleep Apnea Study (TuCASA), a cohort study designed to examine the prevalence and correlates of sleep disordered breathing. A subset of 42 children enrolled in TuCASA who had no symptoms of any sleep disorder and had polysomnograms without technical recording problems.

RESULTS

Sleep architecture in preadolescent Caucasian and Hispanic children was not different between boys and girls. However, total sleep time (TST), sleep efficiency (SLE) and time spent in REM sleep declined with increasing age. In addition, the number of sleep to wake stage shifts was slightly higher in younger children. Hispanic children had less Stage 3/4 sleep (18+/-1 vs. 22+/-1%, P</=0.02) and correspondingly more Stage 2 sleep (55+/-2 vs. 50.0+/-1%, P</=0.02) than their Caucasian counterparts.

CONCLUSIONS

Using unattended home polysomnography, indices of sleep duration and architecture are not different between preadolescent boys and girls. However, with increasing age, TST and SLE decreased. In addition, there are differences in sleep architecture between Caucasians and Hispanics, which may be an important consideration in the evaluation of children with sleep disorders.

Beta EEG activity and insomnia

To date there have been seven studies which find that beta EEG is elevated at around sleep onset and during polysomnographic sleep in patients with insomnia. These findings suggest that insomnia may be characterized by central nervous system (CNS) hyperarousal. In this article, the seven studies are critically reviewed, two theoretical perspectives on beta EEG are presented, and the concept of hyperarousal as a three component process is discussed.

REM sleep in depression is influenced by ethnicity

The influence of ethnicity on the manifestation of EEG sleep changes in depression was studied in 95 patients (21 African-Americans [AA], 17 Asians [AS], 37 Caucasians [C] and 20 Hispanics [H]) with unipolar major depression. Subjects were studied twice for 2 consecutive nights. On the second night of each 2-night session, placebo or scopolamine (1.5 microg/kg, IM, at 23.00 h) was administered. On the baseline (placebo) night, sleep architecture, sleep continuity and rapid eye movement (REM) sleep variables were generally comparable among the groups. However, REM sleep was less in AA and AS subjects than in C and H subjects. Furthermore, the distribution of REM sleep over the course of the night in AA and AS subjects differed significantly from that in the C and H groups. Although scopolamine significantly affected sleep continuity and REM sleep measures, no significant differential effects of scopolamine were observed. Because many antidepressants suppress REM sleep, the differences in baseline REM sleep observed might be related to the greater sensitivity of some ethnic-minority depressed patients to pharmacotherapy.