The longitudinal course of insomnia symptoms: inequalities by sex and occupational class among two different age cohorts followed for 20 years in the west of Scotland

Sleep disorders and cancer incidence: examining duration and severity of diagnosis among veterans

Introduction

Sleep disruption affects biological processes that facilitate carcinogenesis. This retrospective cohort study used de-identified data from the Veterans Administration (VA) electronic medical record system to test the hypothesis that patients with diagnosed sleep disorders had an increased risk of prostate, breast, colorectal, or other cancers (1999-2010, N=663,869). This study builds upon existing evidence by examining whether patients with more severe or longer-duration diagnoses were at a greater risk of these cancers relative to those with a less severe or shorter duration sleep disorder.

Methods

Incident cancer cases were identified in the VA Tumor Registry and sleep disorders were defined by International Classification of Sleep Disorder codes. Analyses were performed using extended Cox regression with sleep disorder diagnosis as a time-varying covariate.

Results

Sleep disorders were present among 56,055 eligible patients (8% of the study population); sleep apnea (46%) and insomnia (40%) were the most common diagnoses. There were 18,181 cancer diagnoses (41% prostate, 12% colorectal, 1% female breast, 46% other). The hazard ratio (HR) for a cancer diagnosis was 1.45 (95% confidence interval [CI]: 1.37, 1.54) among those with any sleep disorder, after adjustment for age, sex, state of residence, and marital status. Risks increased with increasing sleep disorder duration (short [<1-2 years] HR: 1.04 [CI: 1.03-1.06], medium [>2-5 years] 1.23 [1.16-1.32]; long [>5-12 years] 1.52 [1.34-1.73]). Risks also increased with increasing sleep disorder severity using cumulative sleep disorder treatments as a surrogate exposure; African Americans with more severe disorders had greater risks relative to those with fewer treatments and other race groups. Results among patients with only sleep apnea, insomnia, or another sleep disorder were similar to those for all sleep disorders combined.

Discussion

The findings are consistent with other studies indicating that sleep disruption is a cancer risk factor. Optimal sleep and appropriate sleep disorder management are modifiable risk factors that may facilitate cancer prevention.

Validity and Reliability of the Turkish Version of the Sleep Condition Indicator: A Clinical Screening Instrument Based on the DSM-5 Criteria for Insomnia

Purpose

We aimed to adapt the Turkish Sleep Condition Indicator (SCI) version and examine its psychometric properties among the general population.

Methods

This study was a cross-sectional study. The item-total correlation, standard error of measurement, Cronbach's α, and McDonald's ω were used for internal consistency. We ran confirmatory factor analysis (CFA) and network analysis to confirm the factor structure. Multigroup CFA was run to assess the measurement invariance across gender, whether clinical insomnia or not, and poor sleep quality. We correlated SCI scores with Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) scores to evaluate construct validity. A receiver operating characteristic (ROC) curve analysis was conducted to calculate the cut-off score of the SCI. The temporal stability was examined with the intraclass correlation coefficient.

Results

Eight hundred thirty-four participants attended. Over half of the participants were women (63.2% n = 527); the mean age was 36.15 ± 9.64. Confirmatory factor and network analysis results show that the two-factor correlated model had a good model fit for the SCI. The SCI had scalar level invariance across gender, having clinical insomnia and poor sleep quality in the Multigroup CFA. ROC curve analysis shows that the SCI has good sensitivity (90.3%) and specificity (91.8%) for cut-off ≤ 15. The intraclass correlation coefficient computed between the first and second SCI total scores was significant (r=0.80 with a 95% confidence interval from 0.78 to 0.87; p < 0.001).

Conclusion

The Turkish SCI is a practical self-reported insomnia scale with good psychometric properties that can be used to screen for insomnia disorder.

The association between loneliness, social isolation, and sleep disturbances in older adults: A follow-up study from the Swedish good aging in Skåne project

Objectives

The aim of this follow-up study was to investigate whether loneliness and social isolation in a sample of older adults, mean age of 67.4 years at baseline examination, were associated with sleep disturbances at re-examination at a mean age of 76.4 years.

Methods

The study sample consisted of 2897 participants. Data on loneliness, social isolation, and sleep disturbances were collected through questionnaires and medical examinations. Logistic regression models were constructed to identify associations between levels of loneliness and social isolation at baseline and sleep disturbances at follow-up. Sociodemographic and health-related confounding factors were controlled for in the models.

Results

Sleep disturbances were reported by 25.6% (95% CI: 24.0%-27.2%) at baseline and 23.7% (95% CI: 22.1%-25.3%) at re-examination. Odds ratios for sleep disturbances at re-examination in relation to not being lonely or socially isolated were as follows: single occasions of loneliness (OR: 1.37, 95% CI: 1.05-1.78), recurring periods/constant loneliness (OR: 1.92, 95% CI: 1.01-1.99), less severe social isolation (OR: 1.18, 95% CI: 0.78-1.79), and severe social isolation (OR: 1.88, 95% CI: 1.01-3.49).

Discussion

Sleep disturbances are common among older adults and are associated with loneliness and social isolation. Healthcare professionals should be aware of the potential effects of loneliness and social isolation when investigating sleep disturbances in older adults.

Association between sleep duration and burnout in healthcare professionals: a cross-sectional survey

Background

Short sleep duration in healthcare professionals is a recurring concern among researchers. On the other hand, the prevalence of burnout in this population group is experiencing exponential growth. Therefore, this study aimed to explore the association between sleep duration and burnout in healthcare professionals.

Methods

This is a cross-sectional study. Data were collected by applying a non-probabilistic convenience sampling, considering a sample of 300 healthcare professionals from the public sector in Peru. The association between variables was explored using multivariate logistic regression. Values of p < 0.05 were considered statistically significant.

Results

The results of the analysis in the crude models revealed that both men and women who slept < 7 h during workdays and days off were 8.33 (95% CI = 2.68-13.99, p = 0.004) and 17.18 (95% CI = 10.50-23.87, p < 0.001) times more likely to have burnout compared to those who reported ≥7 h, respectively. After adjusting for confounding variables, the association remained statistically significant.

Conclusion

The findings of this study underscore the critical importance of sleep duration in the incidence of burnout among healthcare professionals. In the context of the global challenges to the mental and physical health of these professionals, our results highlight the urgent need to implement strategies at the organizational and individual level. This includes promoting a better work-life balance, and effective stress management and improved sleep quality.

Socioeconomic status and sleep health: a narrative synthesis of 3 decades of empirical research

STUDY OBJECTIVES

This review aims to assess the association between socioeconomic status (SES) and sleep health in the general population and the mediating effects of lifestyle and mental and physical health in this relationship.

METHODS

Observational studies testing the independent association between objective or subjective SES indicators and behavioral/physiological or clinical sleep health variables in the general population were included. PubMed/MEDLINE was searched for reports published from January 1990 to December 2019. The direction of effect was used as the primary effect measure, testing the hypothesis that low SES is associated with poor sleep health outcomes. Results are presented in the form of direction effect plots and synthesized as binomial proportions.

RESULTS

Overall, 336 studies were identified. A high proportion of effects at the expected direction was noted for measures of sleep continuity (100% for sleep latency, 50-100% for awakenings, 66.7-100% for sleep efficiency), symptoms of disturbed sleep (75-94.1% for insomnia, 66.7-100% for sleep-disordered breathing, 60-100% for hypersomnia), and general sleep satisfaction (62.5-100%), while the effect on sleep duration was inconsistent and depended on the specific SES variable (92.3% for subjective SES, 31.7% for employment status). Lifestyle habits, chronic illnesses, and psychological factors were identified as key mediators of the SES-sleep relationship.

CONCLUSIONS

Unhealthy behaviors, increased stress levels, and limited access to health care in low-SES individuals may explain the SES-sleep health gradient. However, the cross-sectional design of most studies and the high heterogeneity in employed measures of SES and sleep limit the quality of evidence. Further research is warranted due to important implications for health issues and policy changes.

CITATION

Papadopoulos D, Etindele Sosso FA. Socioeconomic status and sleep health: a narrative synthesis of 3 decades of empirical research. J Clin Sleep Med. 2023;19(3):605-620.

Assessment of Sex-Dependent Medical Outcomes During Spaceflight

Introduction: In this study sex-differences in medical outcomes during spaceflight are reviewed and probabilistic risk assessment (PRA) is used to assess the impact on spaceflight missions of varying lengths. Materials and Methods: We use PRA to simulate missions of 42 days, 6 months, and 2.5 years. We model medical outcomes using three crews: two men and two women, four women, or four men. Total medical events (TME), crew health index (CHI), probability (0-1) of medical evacuation (pEVAC), probability of loss of crew life (pLOCL), and influential medical conditions were determined. Results: No differences were seen in any metric for the 42-day mission. There were no differences seen for any mission length, in any crew, for TME, CHI, pLOCL, or environmental causes of pEVAC. Sex-dependent differences are seen for rates of nonemergent pEVAC during the 6 month and 2.5-year missions, where women have a higher pEVAC in the 182-day (0.0388 vs. 0.0354) and 2.5-year missions (0.350 vs. 0.228). These differences were driven by higher incidence of partially treated urinary tract infection (UTI). In the 2.5 year mission, with resupply of medical resources, the influence of UTI in women on pEVAC decreases (0.35-0.11). Discussion: Although resupply is unlikely for deep space missions, modeled results suggest that sex-specific medical needs can be readily managed through preventive measures and inclusion of appropriate medical capabilities. Within its many limitations, PRA is a useful tool to estimate medical risks in unique environments where only expert opinion was previously available.

Management of Chronic Insomnia Using Cognitive Behavior Therapy for Insomnia (CBT-I) During COVID-19 Pandemic: Does One Shoe Fit All?

PURPOSE

Insomnia is a highly prevalent disorder that is seen across all age groups causing significant morbidity to the patients. Its prevalence has further risen during COVID-19 pandemic. It is widely acknowledged that untreated insomnia can lead to significant health risks and socio-occupational dysfunction.

METHODS

A narrative review was conducted following focused search of databases.

RESULTS

Available guidelines mention two different approaches for the management of insomnia-pharmacological and non-pharmacological. Non-pharmacological therapies like multicomponent cognitive behavior therapy for insomnia (CBT-I) have been advocated for the management of acute as well as chronic insomnia in the literature as it has been found efficacious and useful. Multiple variants of CBT-I, e.g., digitally delivered CBT-I, brief CBT-I have been tested during pandemic owing to closure of clinics. However, there are certain issues to be considered while choosing CBT-I as therapy. For example, like other forms of psychotherapies, is there a need for assessing the candidature of patient before administering CBT-I; is CBT-I free of adverse effects as commonly thought; is CBT-I more efficacious than hypnotics; and at last, how to manage cases that are not candidate for CBT-I.

CONCLUSION

This narrative review addresses the scientific robustness of evidence for issues related to adherence, efficacy and adverse effects of non-pharmacological therapies. Available literature suggests that data related to adherence and efficacy of CBT-I suffer from methodological shortcomings and careful selection of patient is important for the successful therapy. At the same time, attempts have been made to shed light to the areas where CBT-I can be helpful in the management of insomnia.

Association of objectively measured sleep with frailty and 5-year mortality in community-dwelling older adults

STUDY OBJECTIVES

To determine whether actigraphy-measured sleep was independently associated with risk of frailty and mortality over a 5-year period among older adults.

METHODS

We used data from Waves 2 (W2) and 3 (W3) (2010-2015) of the National Social Life, Health and Aging Project, a prospective cohort of community-dwelling older adults born between 1920 and 1947. One-third of W2 respondents were randomly selected to participate in a sleep study, of whom N = 727 consented and N = 615 were included in the analytic sample. Participants were instructed to wear a wrist actigraph for 72 h (2.93 ± 0.01 nights). Actigraphic sleep parameters were averaged across nights and included total sleep time, percent sleep, sleep fragmentation index, and wake after sleep onset. Subjective sleep was collected via questionnaire. Frailty was assessed using modified Fried Frailty Index. Vital status was ascertained at the time of the W3 interview. W3 frailty/mortality status was analyzed jointly with a four-level variable: robust, pre-frail, frail, and deceased. Associations were modeled per 10-unit increase.

RESULTS

After controlling for baseline frailty (robust and pre-frail categories), age, sex, education, body mass index, and sleep time preference, a higher sleep fragmentation index was associated with frailty (OR = 1.70, 95% CI: 1.02-2.84) and mortality (OR = 2.12, 95% CI: 1.09-4.09). Greater wake after sleep onset (OR = 1.24, 95% CI: 1.02-1.50) and lower percent sleep (OR = 0.41, 95% CI: 0.17-0.97) were associated with mortality.

CONCLUSIONS

Among community-dwelling older adults, actigraphic sleep is associated with frailty and all-cause mortality over a 5-year period. Further investigation is warranted to elucidate the physiological mechanisms underlying these associations.

Influence of socioeconomic status on objective sleep measurement: A systematic review and meta-analysis of actigraphy studies

Social inequities have many health effects; one of these is a potential relationship to sleep disturbances. Socioeconomic status (SES) is an important factor that contributes to social inequities. SES is a marker of living conditions and habits that influence health by way of different processes, including stress-related mechanisms. However, a systematic review of the relationship between SES and objectively measured sleep parameters has not been conducted. Therefore, a systematic review and meta-analysis were performed to examine the relationship between SES and sleep parameters measured with actigraphy in the general population. Nineteen articles were identified and included from a keyword search in Medline/PubMed, Web of Science, and SCOPUS, following PRISMA guidelines. For an article to be included, it had to have a measure of SES and also, an actigraphy-based measure of sleep. For, included studies, qualitative and quantitative data were extracted, and study quality was assessed with The National Institute of Health's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Bivariate correlations were extracted and entered into a meta-analysis, along with a qualitative review of articles. These analyses revealed that SES was associated with sleep parameters in the predicted direction, with lower SES associated with worse sleep parameters. Specifically, lower SES was associated with lower total sleep time, longer sleep latency, greater sleep fragmentation, and higher variability in sleep onset and sleep latency. Higher education, higher perceived economic well-being, and higher income were significantly associated with improved sleep efficiency and longer sleep duration. For the 19 articles included, 10 were rated as fair or poor in study quality. Thus, higher quality studies in this area are needed. This meta-analysis and systematic review demonstrated that social inequities of sleep can be measured objectively, opening the path to the development and integration of methodologies combining actigraphy with current subjective measures for utilization in clinical practice.

Time-Varying Insomnia Symptoms and Incidence of Cognitive Impairment and Dementia among Older US Adults

There is conflicting evidence regarding the association between insomnia and the onset of mild cognitive impairment (MCI) or dementia. This study aimed to evaluate if time-varying insomnia is associated with the development of MCI and dementia. Data from the Health and Retirement Study (n = 13,833) from 2002 to 2014 were used (59.4% female). The Brief Insomnia Questionnaire was used to identify insomnia symptoms which were compiled in an insomnia severity index, ranging from 0 to 4. In analysis, participants' symptoms could vary from wave-to-wave. Dementia was defined using results from the Health and Retirement Study (HRS) global cognitive assessment tool. Respondents were classified as either having dementia, MCI, or being cognitively healthy. Cox proportional hazards models with time-dependent exposure using the counting process (start-stop time) were used for analysis. For each one-unit increase in the insomnia symptom index, there was a 5-percent greater hazard of MCI (HR = 1.05; 95% CI: 1.04-1.06) and dementia (HR = 1.05; 95% CI: 1.03-1.05), after fully adjusting. Using a nationally representative sample of adults age 51 and older, this study found that time-varying insomnia symptoms are associated with risk of MCI and dementia. This highlights the importance of identifying sleep disturbances and their change over time as potentially important risk factors for MCI and dementia.

People with dyssomnia showed increased vulnerability to CoVID-19 pandemic: a questionnaire-based study exploring the patterns and predictors of sleep quality using the latent class analysis technique in Indian population

INTRODUCTION

CoVID-19 pandemic and the subsequent lockdown have impacted the sleep quality and the overall wellbeing of mankind. The present epidemiological study measured various aspects of sleep disturbance such as sleep quality, daytime impairments, negative emotionality, sleep hygiene, and well-being associated with CoVID-19 pandemic among the Indian population.

METHODS

This cross-sectional voluntary online survey (using Google form) was communicated across the country from 4th June to 3rd July 2020 through mail and social media applications. The responses received (N = 450) were categorized and validated using the latent class analysis and logistic regression tests respectively, and the classes and subclasses derived were profiled. These techniques are used for the first time in a CoVID-19 sleep study.

RESULTS

Out of the three classes derived from the LCA, people with severe dyssomnia belonging to class 1 (33.3%) showed high daytime impairments, negative emotionality and high vulnerability towards CoVID-19 pandemic measures. In addition, the two subclasses derived from the severe dyssomnia group; one with negative emotionality predominance and the other with excessive daytime sleepiness, were similarly affected by CoVID-19 measures. People with moderate dyssomnia (class 2, 28.5%) showed frequent arousals with daytime impairments and the majority (38.2%) which fell in to class 3, the 'no dyssomnia' category, were not impacted by CoVID-19 pandemic.

CONCLUSION

People with existing sleep problems or those who were vulnerable to the same were the ones affected by CoVID-19 pandemic. Those with inadequate emotional coping styles have showed heightened vulnerability. Proper medical and cognitive interventions are highly recommended for this population. No or moderate dyssomnia categories (class 3 and 2 respectively) were less impacted by CoVID-19.

The Different Faces of Insomnia

Objectives: The identification of clinically relevant subtypes of insomnia is important. Including a comprehensive literature review, this study also introduces new phenotypical relevant parameters by describing a specific insomnia cohort. Methods: Patients visiting the sleep center and indicating self-reported signs of insomnia were examined by a sleep specialist who confirmed an insomnia diagnosis. A 14-item insomnia questionnaire on symptoms, progression, sleep history and treatment, was part of the clinical routine. Results: A cohort of 456 insomnia patients was described (56% women, mean age 52 ± 16 years). They had suffered from symptoms for about 12 ± 11 years before seeing a sleep specialist. About 40-50% mentioned a trigger (most frequently psychological triggers), a history of being bad sleepers to begin with, a family history of sleep problems, and a negative progression of insomnia. Over one third were not able to fall asleep during the day. SMI (sleep maintenance insomnia) symptoms were most frequent, but only prevalence of EMA (early morning awakening) symptoms significantly increased from 40 to 45% over time. Alternative non-medical treatments were effective in fewer than 10% of cases. Conclusion: Our specific cohort displayed a long history of suffering and the sleep specialist is usually not the first point of contact. We aimed to describe specific characteristics of insomnia with a simple questionnaire, containing questions (e.g., ability to fall asleep during the day, effects of non-medical therapy methods, symptom stability) not yet commonly asked and of unknown clinical relevance as yet. We suggest adding them to anamnesis to help differentiate the severity of insomnia and initiate further research, leading to a better understanding of the severity of insomnia and individualized therapy. This study is part of a specific Research Topic introduced by Frontiers on the heterogeneity of insomnia and its comorbidity and will hopefully inspire more research in this area.

Daytime Neurophysiological Hyperarousal in Chronic Insomnia: A Study of qEEG

Background: The hyperarousal model demonstrates that instability of sleep-wake regulation leads to insomnia symptoms and various neurophysiological hyperarousal states. Previous studies have shown that hyperarousal states that appear in chronic insomnia patients are not limited to sleep at nighttime but are stable characteristics that extend into the daytime. However, this phenomenon is mainly measured at bedtime, so it hard to determine whether it is maintained throughout a 24 h cycle or if it just appears at bedtime. Methods: We examined the resting state qEEG (quantitative electroencephalogram) and ECG (electrocardiogram) of chronic insomnia patients (n = 24) compared to good sleepers (n = 22) during the daytime. Results: As compared with controls, participants with insomnia showed a clearly high beta band activity in eyes closed condition at all brain areas. They showed a low frequency band at the frontal area; high frequency bands at the central and parietal areas were found in eyes open condition. Significantly higher heart rates were also found in the chronic insomnia group. Conclusion: These findings suggest that chronic insomnia patients were in a state of neurophysiological hyperarousal during the middle of the day due to abnormal arousal regulation.

Subgrouping Poor Sleep Quality in Community-Dwelling Older Adults with Latent Class Analysis - The Yilan Study, Taiwan

The manifestation of older adults with poor sleep quality is heterogeneous. Using data-driven classifying methods, the study aims to subgroup community-dwelling older adults with poor sleep quality. Adults aged 65 and older participated in the Yilan study. Poor sleep quality was defined using the Pittsburgh Sleep Quality Index. Latent class analysis with the 7 subscores of the Pittsburgh Sleep Quality Index as the indicators was used to generate empirical subgroups. Differences in comorbidity patterns between subgroups were compared. A total of 2622 individuals, of which 1011 (38.6%) had Pittsburgh Sleep Quality Index -defined poor sleep quality, participated. Three groups for poor sleep quality were specified in the latent class analysis: High Insomnia (n = 191, 7.3%), Mild Insomnia (n = 574, 21.9%), and High Hypnotics (n = 246, 9.4%). The High Insomnia and Mild Insomnia groups shared similar profiles but different severities in the 7 domains of the Pittsburgh Sleep Quality Index. In contrast, the High Hypnotics group had the lowest Pittsburgh Sleep Quality Index total scores and insomnia severity but had similar mental and physical comorbid patterns as the High Insomnia group. This finding suggests that poor sleep quality in community-dwelling older adults had various feature-based subgroups. It also implicates the development of group-centered interventions.

Heightened sleep propensity: a novel and high-risk sleep health phenotype in older adults

OBJECTIVES

To reveal sleep health phenotypes in older adults and examine their associations with time to 5-year all-cause and cardiovascular mortality.

DESIGN

Prospective longitudinal cohorts.

SETTING

The Study of Osteoporotic Fractures and Outcomes of Sleep Disorders in Older Men Study.

PARTICIPANTS

N = 1722 men and women aged ≥65 years matched 1:1 on sociodemographic and clinical measures.

MEASUREMENTS

Self-reported habitual sleep health characteristics (satisfaction, daytime sleepiness, timing, efficiency, and duration) measured at an initial visit and longitudinal follow-up for mortality.

RESULTS

Latent class analysis revealed 3 sleep health phenotypes: (1) heightened sleep propensity (HSP; medium to long duration, high sleepiness, high efficiency/satisfaction; n = 322), (2) average sleep (AS; medium duration, average efficiency, high satisfaction, low sleepiness; n = 1,109), and (3) insomnia with short sleep (ISS; short to medium duration, low efficiency/satisfaction, moderate sleepiness; n = 291). Phenotype predicted time to all-cause mortality (χ2 = 9.4, P = .01), with HSP conferring greater risk than AS (hazard ratio [95% confidence interval] = 1.48 [1.15-1.92]) or ISS (1.52 [1.07-2.17]), despite ISS reporting the poorest mental and physical health. Although sex did not formally moderate the relationship between phenotype and mortality, subgroup analyses indicated that these findings were driven primarily by women. Phenotype did not predict cardiovascular mortality.

CONCLUSIONS

These analyses support the utility of examining multidimensional sleep health profiles by suggesting that the combination of long sleep, high efficiency/satisfaction, and daytime sleepiness-previously identified as independent risk factors-may be components of a single high-risk sleep phenotype, HSP. Further investigation of sex differences and the mechanisms underlying mortality risk associated with HSP is warranted.

Work and Health Correlates of Sleep Quantity and Quality Among Correctional Nurses

BACKGROUND/OBJECTIVES

The correctional environment exposes nurses to unique physical and psychosocial work stressors, such as inmate violence and safety concerns. Nurses often experience short and poor sleep; however, the quantity and quality of sleep in this specialty practice group of nurses are underexplored. The study objective was to examine a wide range of work and health correlates of sleep quantity and quality in correctional nurses.

METHODS

A Web-based survey was administered to nurses within a Northeastern State Correctional Healthcare System, covering questions on sleep quantity and quality, working conditions, health outcomes, and work outcomes.

RESULTS

Among the 89 correctional nurses who participated, 56.2% reported short sleep duration (≤6 hours/day) and 31.8% reported poor sleep quality. Multivariate Poisson regression modeling suggested that night shift (prevalence ratio [PR] = 1.95, p < 0.05) and single marital status (PR = 2.25, p < 0.05) were significantly associated with increased prevalence of short sleep duration, whereas none of the work and health variables were significantly associated with increased prevalence of poor sleep quality, after adjustment for sociodemographics and other covariates.

CONCLUSION

Correctional nurses experience a high prevalence of short and poor sleep. Similar to previous studies, we found that short sleep duration was associated with night shift work. Interventions targeting work schedule remodeling (e.g., reduce the number of consecutive night shifts) and shift work coping mechanisms may promote sleep health of correctional nurses.

Sleep, Health, and Society

Biological needs for sleep are met by engaging in behaviors that are largely influenced by the environment, social norms and demands, and societal influences and pressures. Insufficient sleep duration and sleep disorders such as insomnia and sleep apnea are highly prevalent in the US population. This article outlines some of these downstream factors, including cardiovascular and metabolic disease risk, neurocognitive dysfunction, and mortality, as well as societal factors such as age, sex, race/ethnicity, and socioeconomics. This review also discusses societal factors related to sleep, such as globalization, health disparities, public policy, public safety, and changing patterns of use of technology.

Identifying At-Risk Individuals for Insomnia Using the Ford Insomnia Response to Stress Test

STUDY OBJECTIVES

A primary focus of the National Institute of Mental Health's current strategic plan is "predicting" who is at risk for disease. As such, the current investigation examined the utility of premorbid sleep reactivity in identifying a specific and manageable population at elevated risk for future insomnia.

METHODS

A community-based sample of adults (n = 2,892; 59.3% female; 47.9 ± 13.3 y old) with no lifetime history of insomnia or depression completed web-based surveys across three annual assessments. Participants reported parental history of insomnia, demographic characteristics, sleep reactivity on the Ford Insomnia in Response to Stress Test (FIRST), and insomnia symptoms. DSM-IV diagnostic criteria were used to determine insomnia classification.

RESULTS

Baseline FIRST scores were used to predict incident insomnia at 1-y follow-up. Two clinically meaningful FIRST cutoff values were identified: FIRST ≥ 16 (sensitivity 77%; specificity 50%; odds ratio [OR] = 2.88, P < 0.001); and FIRST ≥ 18 (sensitivity 62%; specificity 67%; OR = 3.32, P < 0.001). Notably, both FIRST cut-points outperformed known maternal (OR = 1.49-1.59, P < 0.01) and paternal history (P = NS) in predicting insomnia onset, even after controlling for stress exposure and demographic characteristics. Of the incident cases, insomniacs with highly reactive sleep systems reported longer sleep onset latencies (FIRST ≥ 16: 65 min; FIRST ≥ 18: 68 min) than participants with nonreactive insomnia (FIRST < 16: 37 min; FIRST < 18: 44 min); these groups did not differ on any other sleep parameters.

CONCLUSIONS

The current study established a cost- and time-effective strategy for identifying individuals at elevated risk for insomnia based on trait sleep reactivity. The FIRST accurately identifies a focused target population in which the psychobiological processes complicit in insomnia onset and progression can be better investigated, thus improving future preventive efforts.

Contributing influences of work environment on sleep quantity and quality of nursing assistants in long-term care facilities: A cross-sectional study

The effect of shift work on nurses' sleep is well-studied, but there are other challenging aspects of health care work that might also affect the sleep of direct caregivers. This study examined the influence of the long-term care work environment on sleep quantity and quality of nursing assistants. A cross-sectional survey collected data from 650 nursing assistants in 15 long-term care facilities; 46% reported short sleep duration and 23% reported poor sleep quality. A simple additive index of the number of beneficial work features (up to 7) was constructed for analysis with Poisson regression. With each unit increase of beneficial work features, nursing assistants were 7% less likely to report short sleep duration and 17% less likely to report poor sleep quality. These results suggest that effective workplace interventions should address a variety of work stressors, not only work schedule arrangements, in order to improve nursing assistants' sleep health.

Symptoms of Insomnia and Sleep Duration and Their Association with Incident Strokes: Findings from the Population-Based MONICA/KORA Augsburg Cohort Study

Objective

To examine the relationship between symptoms of insomnia and sleep duration and incident total (non-fatal plus fatal) strokes, non-fatal strokes, and fatal strokes in a large cohort of men and women from the general population in Germany.

Methods

In four population-based MONICA (monitoring trends and determinants in cardiovascular disease)/KORA (Cooperative Health Research in the Region of Augsburg) surveys conducted between 1984 and 2001, 17,604 men and women (aged 25 to 74 years) were asked about issues like sleep, health behavior, and medical history. In subsequent surveys and mortality follow-ups, incident stroke cases (cerebral hemorrhage, ischemic stroke, transient ischemic attack, unknown stroke type) were gathered prospectively until 2009. Sex-specific hazard ratios (HR) and their 95% confidence intervals (CI) were estimated using sequential Cox proportional hazards regression models.

Results

During a mean follow-up of 14 years, 917 strokes (710 non-fatal strokes and 207 fatal strokes) were observed. Trouble falling asleep and difficulty staying asleep were not significantly related to any incident stroke outcome in either sex in the multivariable models. Among men, the HR for the association between short (≤5 hours) and long (≥10 hours) daily sleep duration and total strokes were 1.44 (95% CI: 1.01–2.06) and 1.63 (95% CI: 1.16–2.29), after adjustment for basic confounding variables. As for non-fatal strokes and fatal strokes, in the analyses adjusted for age, survey, education, physical activity, alcohol consumption, smoking habits, body mass index, hypertension, diabetes, and dyslipidemia, the increased risks persisted, albeit somewhat attenuated, but no longer remained significant. Among women, in the multivariable analyses the quantity of sleep was also not related to any stroke outcome.

Conclusion

In the present study, symptoms of insomnia and exceptional sleep duration were not significantly predictive of incident total strokes, non-fatal strokes, and fatal strokes in either sex.

Organizational justice and insomnia: Relationships between justice components and insomnia symptoms among private company workers in Japan

OBJECTIVES

Organizational justice (OJ) is an important psychosocial factor and it consists of several components. Previous studies have shown that low perceived OJ is associated with various health problems. However, the relationships between each justice component and health outcomes have not been fully examined. The purpose of this study was to clarify the relationships between OJ and insomnia, including OJ components and insomnia symptoms.

METHODS

Cross-sectional self-reported questionnaire data from 1,893 employees (92.2% of subjects) were collected. OJ was measured using the Japanese version of the OJ questionnaire, which has four components (distributive, procedural, interpersonal and informational). Insomnia was assessed with the Athens Insomnia Scale. Logistic regression analysis, with insomnia as a dependent variable and OJ as an independent variable, was conducted.

RESULTS

Subjects with low overall OJ had a higher risk of insomnia (adjusted odds ratio (AOR), 2.37; 95% confidence interval (CI), 1.59 to 3.53) and two insomnia symptoms (AOR of 2.47 and 95% CI of 1.68 to 3.65 for sleep induction problem; AOR of 1.73 and 95% CI of 1.21 to 2.48 for sleep maintenance problem). The four justice components were all associated with insomnia and sleep induction problems. Sleep maintenance problems were associated with only the distributive justice component.

CONCLUSIONS

All four justice components were associated with both insomnia and sleep induction problems. Sleep maintenance problems, however, showed different features. Specifically, the distributive justice component seemed to be a key factor in the relationship between OJ and insomnia. These findings might provide useful information for preventing the adverse effects of insomnia.

Risk factors for sleep disturbances in older adults: Evidence from prospective studies

No systematic review of epidemiological evidence has examined risk factors for sleep disturbances among older adults. We searched the PubMed database combining search terms targeting the following domains 1) prospective, 2) sleep, and 3) aging, and identified 21 relevant population-based studies with prospective sleep outcome data. Only two studies utilized objective measures of sleep disturbance, while six used the Pittsburgh sleep quality index (PSQI) and thirteen used insomnia symptoms or other sleep complaints as the outcome measure. Female gender, depressed mood, and physical illness were most consistently identified as risks for future sleep disturbances. Less robust evidence implicated the following as potentially relevant predictors: lower physical activity levels, African-American race, lower economic status, previous manual occupation, widowhood, marital quality, loneliness and perceived stress, preclinical dementia, long-term benzodiazepine and sedative use, low testosterone levels, and inflammatory markers. Chronological age was not identified as a consistent, independent predictor of future sleep disturbances. In conclusion, prospective studies have identified female gender, depressed mood, and physical illness as general risk factors for future sleep disturbances in later life, although specific physiological pathways have not yet been established. Research is needed to determine the precise mechanisms through which these factors influence sleep over time.

Quantitative measures of nocturnal insomnia symptoms predict greater deficits across multiple daytime impairment domains

This study examined the associations between reported quantitative sleep measures and multiple daytime impairment domains. We collected data from a subsample of adults (n = 513) from the Colorado Longitudinal Twin Study and Community Twin Study. Results revealed that greater insomnia symptom frequency (days per week) significantly predicted greater global sleep-related functional impairment and depressive symptoms. Sleep onset latency was also positively associated with depressive symptoms. Receiver operating characteristic curve analyses indicated 3-4 nights per week and 36-40 min provided optimal sensitivity and specificity for impairment. Thus, insomnia frequency and sleep latency are critical in understanding the impact of insomnia on multiple impairment domains. Using functional impairment as criterion, these findings also support the use of specific quantitative cutoffs for sleep measures in diagnostic systems.

The nature of stable insomnia phenotypes

STUDY OBJECTIVES

We examined the 1-y stability of four insomnia symptom profiles: sleep onset insomnia; sleep maintenance insomnia; combined onset and maintenance insomnia; and neither criterion (i.e., insomnia cases that do not meet quantitative thresholds for onset or maintenance problems). Insomnia cases that exhibited the same symptom profile over a 1-y period were considered to be phenotypes, and were compared in terms of clinical and demographic characteristics.

DESIGN

Longitudinal.

SETTING

Urban, community-based.

PARTICIPANTS

Nine hundred fifty-four adults with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition based current insomnia (46.6 ± 12.6 y; 69.4% female).

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

At baseline, participants were divided into four symptom profile groups based on quantitative criteria. Follow-up assessment 1 y later revealed that approximately 60% of participants retained the same symptom profile, and were hence judged to be phenotypes. Stability varied significantly by phenotype, such that sleep onset insomnia (SOI) was the least stable (42%), whereas combined insomnia (CI) was the most stable (69%). Baseline symptom groups (cross-sectionally defined) differed significantly across various clinical indices, including daytime impairment, depression, and anxiety. Importantly, however, a comparison of stable phenotypes (longitudinally defined) did not reveal any differences in impairment or comorbid psychopathology. Another interesting finding was that whereas all other insomnia phenotypes showed evidence of an elevated wake drive both at night and during the day, the 'neither criterion' phenotype did not; this latter phenotype exhibited significantly higher daytime sleepiness despite subthreshold onset and maintenance difficulties.

CONCLUSIONS

By adopting a stringent, stability-based definition, this study offers timely and important data on the longitudinal trajectory of specific insomnia phenotypes. With the exception of daytime sleepiness, few clinical differences are apparent across stable phenotypes.

Latent class analysis was accurate but sensitive in data simulations

OBJECTIVES

Latent class methods are increasingly being used in analysis of developmental trajectories. A recent simulation study by Twisk and Hoekstra (2012) suggested caution in use of these methods because they failed to accurately identify developmental patterns that had been artificially imposed on a real data set. This article tests whether existing developmental patterns within the data set used might have obscured the imposed patterns.

STUDY DESIGN AND SETTING

Data were simulated to match the latent class pattern in the previous article, but with varying levels of randomly generated variance, rather than variance carried over from a real data set. Latent class analysis (LCA) was then used to see if the latent class structure could be accurately identified.

RESULTS

LCA performed very well at identifying the simulated latent class structure, even when the level of variance was similar to that reported in the previous study, although misclassification began to be more problematic with considerably higher levels of variance.

CONCLUSION

The failure of LCA to replicate the imposed patterns in the previous study may have been because it was sensitive enough to detect residual patterns of population heterogeneity within the altered data. LCA performs well at classifying developmental trajectories.

Social class and gender patterning of insomnia symptoms and psychiatric distress: a 20-year prospective cohort study

BACKGROUND

Psychiatric distress and insomnia symptoms exhibit similar patterning by gender and socioeconomic position. Prospective evidence indicates a bi-directional relationship between psychiatric distress and insomnia symptoms so similarities in social patterning may not be coincidental. Treatment for insomnia can also improve distress outcomes. We investigate the extent to which the prospective patterning of distress over 20 years is associated with insomnia symptoms over that period.

METHODS

999 respondents to the Twenty-07 Study had been followed for 20 years from approximately ages 36-57 (73.2% of the living baseline sample). Psychiatric distress was measured using the GHQ-12 at baseline and at 20-year follow-up. Gender and social class were ascertained at baseline. Insomnia symptoms were self-reported approximately every five years. Latent class analysis was used to classify patterns of insomnia symptoms over the 20 years. Structural Equation Models were used to assess how much of the social patterning of distress was associated with insomnia symptoms. Missing data was addressed with a combination of multiple-imputation and weighting.

RESULTS

Patterns of insomnia symptoms over 20 years were classified as either healthy, episodic, developing or chronic. Respondents from a manual social class were more likely to experience episodic, developing or chronic patterns than those from non-manual occupations but this was mostly explained by baseline psychiatric distress. People in manual occupations experiencing psychiatric distress however were particularly likely to experience chronic patterns of insomnia symptoms. Women were more likely to experience a developing pattern than men, independent of baseline distress. Psychiatric distress was more persistent over the 20 years for those in manual social classes and this effect disappeared when adjusting for insomnia symptoms. Irrespective of baseline symptoms, women, and especially those in a manual social class, were more likely than men to experience distress at age 57. This overall association for gender, but not the interaction with social class, was explained after adjusting for insomnia symptoms. Sensitivity analyses supported these findings.

CONCLUSIONS

Gender and socioeconomic inequalities in psychiatric distress are strongly associated with inequalities in insomnia symptoms. Treatment of insomnia or measures to promote healthier sleeping may therefore help alleviate inequalities in psychiatric distress.

The Sleep Condition Indicator: a clinical screening tool to evaluate insomnia disorder

OBJECTIVE

Describe the development and psychometric validation of a brief scale (the Sleep Condition Indicator (SCI)) to evaluate insomnia disorder in everyday clinical practice.

DESIGN

The SCI was evaluated across five study samples. Content validity, internal consistency and concurrent validity were investigated.

PARTICIPANTS

30 941 individuals (71% female) completed the SCI along with other descriptive demographic and clinical information.

SETTING

Data acquired on dedicated websites.

RESULTS

The eight-item SCI (concerns about getting to sleep, remaining asleep, sleep quality, daytime personal functioning, daytime performance, duration of sleep problem, nights per week having a sleep problem and extent troubled by poor sleep) had robust internal consistency (α≥0.86) and showed convergent validity with the Pittsburgh Sleep Quality Index and Insomnia Severity Index. A two-item short-form (SCI-02: nights per week having a sleep problem, extent troubled by poor sleep), derived using linear regression modelling, correlated strongly with the SCI total score (r=0.90).

CONCLUSIONS

The SCI has potential as a clinical screening tool for appraising insomnia symptoms against Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria.

Physical activity and sleep profiles in Finnish men and women

Background

Physical activity (PA) and sleep are related to cardiovascular diseases (CVD) and their risk factors. The interrelationship between these behaviors has been studied, but there remain questions regarding the association of different types of PA, such as occupational, commuting, and leisure time to sleep, including quality, duration and sufficiency. It is also unclear to what extent sleep affects peoples’ PA levels and patterns. Our aim is to investigate the interrelationship between PA and sleep behaviors in the Finnish population, including employment status and gender.

Methods

The study comprised population based data from the FINRISK 2012 Study. A stratified, random sample of 10,000 Finns, 25 to 74 years-old, were sent a questionnaire and an invitation to a health examination. The participation rate was 64% (n = 6,414). Latent class analysis was used to search for different underlying profiles of PA and sleep behavior in men and women, respectively. Models with one through five latent profiles were fitted to the data. Based on fit indicators, a four-class model for men and women, respectively, was decided to be the best fitted model.

Results

Four different profiles of PA and sleep were found in both men and women. The most common profile of men comprised 45% of the total participants, and in women, 47%. These profiles were distinguished by probabilities for high leisure time PA and sleep, subjectively rated as sufficient, as well as sleep duration of 7–7.9 hours. The least common profiles represented 5% (men) and 11% (women) of the population, and were characterized by probabilities for physical inactivity, short sleep, and evening type for women and morning type for men. There was also one profile in both genders characterized by likelihood for both high occupational PA and subjectively experienced insufficient sleep.

Conclusions

The use of latent class analysis in investigating the interrelationship between PA and sleep is a novel perspective. The method provides information on the clustering of behaviors in people and the profiles found suggest an accumulative nature of leisure time PA, and better sleep. Our data also suggest that high levels of occupational PA are associated with shorter and poorer sleep.

Social ties may play a critical role in mitigating sleep difficulties in disaster-affected communities: a cross-sectional study in the Ishinomaki area, Japan

STUDY OBJECTIVES

We examined the association between social factors and sleep difficulties among the victims remaining at home in the Ishinomaki area after the Great East Japan Earthquake and Tsunami and identified potentially modifiable factors that may mitigate vulnerability to sleep difficulties during future traumatic events or disasters.

DESIGN

A cross-sectional household survey was conducted from October 2011 to March 2012 (6-12 mo after the disaster) in the Ishinomaki area, Japan. Univariate and multivariate logistic regression models were used to examine associations between social factors and sleep difficulties.

PARTICIPANTS

We obtained data on 4,176 household members who remained in their homes after the earthquake and tsunami.

INTERVENTIONS

N/A.

RESULTS

Sleep difficulties were prevalent in 15.0% of the respondents (9.2% male, 20.2% female). Two potentially modifiable factors (lack of pleasure in life and lack of interaction with/visiting neighbors) and three nonmodifiable or hardly modifiable factors (sex, source of income, and number of household members) were associated with sleep difficulties. Nonmodifiable or hardly modifiable consequences caused directly by the disaster (severity of house damage, change in family structure, and change in working status) were not significantly associated with sleep difficulties.

CONCLUSIONS

Our data suggest that the lack of pleasure in life and relatively strong networks in the neighborhood, which are potentially modifiable, might have stronger associations with sleep difficulties than do nonmodifiable or hardly modifiable consequences of the disaster (e.g., house damage, change in family structure, and change in work status).

Longitudinal trends of the healthcare-seeking prevalence and incidence of insomnia in Taiwan: an 8-year nationally representative study

OBJECTIVES

We used insurance claims of a nationally representative population-based cohort to assess the longitudinal healthcare-seeking prevalence and incidence of insomnia.

METHODS

Participants were identified from National Health Insurance enrollees in Taiwan during 2002 to 2009. Individuals with insomnia were identified using The International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic and procedure codes of 780.52, 307.41, and 307.42.

RESULTS

In 2009 the prevalence of insomnia was 5.4% for women and 3.0% for men; the incidence of insomnia was 1.6% for women and 1.3% for men. Patients who were women (odds ratio [OR]), 1.82; 95% confidence interval [CI], 1.79-1.86), who were older (50-64 years: OR, 23.25; 95% CI, 21.07-25.64; ≥ 65 years: OR, 24.70; 95% CI, 22.40-27.24), and who were in the middle socioeconomic status (SES) group (OR, 1.19; 95% CI, 1.16-1.21) were more likely to have insomnia. An inverse U-shaped woman-to-man ratio trend for the insomnia prevalence was found, and this ratio reached a peak around the menopausal transitional period.

CONCLUSIONS

The persistence of healthcare-seeking behaviors with insomnia was more common in women. Our findings underscore the need to initiate treatment at an early stage as opposed to waiting for the spontaneous resolution of insomnia. Future research needs to identify causes of the persistence of insomnia and to develop proper interventions to reduce its rising prevalence. More active approaches toward preventive strategies for insomnia are needed, especially for women who are at higher risk for insomnia.

Patterns of sleep quality during and after postacute rehabilitation in older adults: a latent class analysis approach

Sleep quality is related to emotional, physical, psychological and cognitive functioning and functional independence in later life. After acute health events, older adults are likely to utilize postacute rehabilitation services to improve functioning and facilitate return to independent living. Patterns of how sleep changes with postacute rehabilitation, and predictors of such patterns, are unknown. The current investigation employed latent class analysis (LCA) methods to classify older adults (n = 233) into groups based on patterns of self-reported sleep quality pre-illness, during postacute rehabilitation and up to 1 year following postacute rehabilitation. Using LCA, older adults were grouped into (1) consistently good sleepers (46%), (2) good sleepers who transitioned into poor sleepers (34%), (3) consistently poor sleepers (14%) and (4) poor sleepers who transitioned into good sleepers (6%). In three planned analyses, pain was an independent predictor of membership in classes 1 or 2 (good pre-illness sleep quality) versus classes 3 or 4 (poor pre-illness sleep quality), and of membership in class 1 (consistently good sleep) versus class 2 (good sleep that transitioned to poor sleep). A lower Mini-Mental State Examination score was a predictor of membership in class 1 versus class 2. There were no statistically significant predictors of membership in class 3 versus class 4. Demographics, comorbidities and depressive symptoms were not significant predictors of class membership. These findings have implications for identification of older adults at risk for developing poor sleep associated with changes in health and postacute rehabilitation. The findings also suggest that pain symptoms should be targeted to improve sleep during postacute rehabilitation.

The pathophysiology of insomnia: from models to molecules (and back)

PURPOSE OF REVIEW

To provide an overview of foundational theories on the psychosocial and neurobiological mechanisms that underlie the pathophysiology of insomnia, a review of recent findings from across the spectrum of sleep sciences that are germane to conceptualizations of insomnia, and how such findings contribute to newer integrative models.

RECENT FINDINGS

Recent findings come from a broad diversity of the sleep research spectrum including basic animal science, sleep neuroscience, especially sleep-wake regulation, psychoneuroimmunology, human genetics, epidemiology, psychology, and from the clinical research realm.

SUMMARY

Our review focuses on the factors contributing to insomnia and to its maintenance over time as well as the theoretical models developed (and developing) to explain this pathophysiology. Early theoretical contributions have provided a backbone for insomnia research; the sleep sciences, in turn, have supported novel and increasingly complex theoretical models of insomnia. The overarching contention is that integrative models are needed that are fully comprehensive in scope.