Validation of self-reported sleep against actigraphy

Practical aspects of actigraphy and approaches in clinical and research domains

Actigraphy involves acquisition of data using a movement sensor worn continuously on the nondominant wrist, typically for a week or more. Computer-based algorithms estimate sleep episodes by analysis of continuous minutes of no to low movement, or spans of time when movement is relatively low compared with movements during presumed ambulatory wakefulness. Inherent advantages of actigraphy over polysomnography include its noninvasive nature, cost-effectiveness, lesser burden on patients/research participants, and ability to collect data over multiple days/nights, thereby allowing examination of sleep-wake patterning. Therefore, actigraphy is emerging as a common method to objectively assess sleep parameters providing estimates of sleep duration and continuity. Modes of actigraphy data collection, scoring algorithms, sleep quality/disturbance measures, validation studies, and clinical and research applications are discussed.

The Relationship Between Tobacco Smoking, Cortisol Secretion, and Sleep Continuity

Background: Existing theories hold that chronic tobacco smoking leads to the development of adverse psychological symptoms, thus producing a compulsive urge to smoke in order to alleviate these sensations. Sleep disturbances are often considered among the negative consequences of chronic smoking. Objectives: The current study aimed at examining whether dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) axis may be involved in this disruption of sleep quality among smokers. Methods: Smokers and non-smokers provided saliva samples following awakening for assessment of cortisol concentrations as a measure of HPA activity. Subsequently the participants completed the State-Trait Anxiety Inventory, Brief Questionnaire on Smoking Urges, the Fagerstrom Test for Nicotine Dependence, and the Pittsburgh Sleep Quality Index. Next, their sleep was monitored objectively for one week using an actigraph. Results: While smokers' self-reported sleep quality was similar to that of non-smokers, their sleep recording data pointed to diminished sleep continuity (increased wake time after sleep onset; WASO), while total sleep time and sleep onset latency were similar to that of non-smokers. Cortisol secretion was higher among smokers. However, among smokers only, cortisol was negatively correlated with WASO, suggesting that the direct enhancing effect of smoking on WASO is somewhat balanced by an indirect process related to higher cortisol levels. Possible interpretations for this inconsistent mediation are discussed. Conclusions/Importance: Smoking is associated with reduced sleep continuity and the relationship between smoking and sleep continuity may involve the HPA axis.

Sleeping hours: what is the ideal number and how does age impact this?

The objective of this narrative review paper is to discuss about sleep duration needed across the lifespan. Sleep duration varies widely across the lifespan and shows an inverse relationship with age. Sleep duration recommendations issued by public health authorities are important for surveillance and help to inform the population of interventions, policies, and healthy sleep behaviors. However, the ideal amount of sleep required each night can vary between different individuals due to genetic factors and other reasons, and it is important to adapt our recommendations on a case-by-case basis. Sleep duration recommendations (public health approach) are well suited to provide guidance at the population-level standpoint, while advice at the individual level (eg, in clinic) should be individualized to the reality of each person. A generally valid assumption is that individuals obtain the right amount of sleep if they wake up feeling well rested and perform well during the day. Beyond sleep quantity, other important sleep characteristics should be considered such as sleep quality and sleep timing (bedtime and wake-up time). In conclusion, the important inter-individual variability in sleep needs across the life cycle implies that there is no "magic number" for the ideal duration of sleep. However, it is important to continue to promote sleep health for all. Sleep is not a waste of time and should receive the same level of attention as nutrition and exercise in the package for good health.

Impacts of nocturnal breastfeeding, photoperiod, and access to electricity on maternal sleep behaviors in a non-industrial rural Bolivian population

OBJECTIVES

We tested 4 main predictions, derived from life history theory and self-evident human diurnality, regarding maternal sleep behaviors in a non-industrialized population in which mother-nursling co-sleeping is universal and prolonged: (1) Night breastfeeding incurs a sleep cost to co-sleeping mothers; (2) Night breastfeeding increases with infant age, causing mothers to sleep less; (3) Sleep duration co-varies with darkness duration; (4) Access to electricity reduces sleep duration.

DESIGN

Mothers self-recorded and reported nursing and sleep behaviors for a 48-hour period once per month (median = 5 months).

SETTING

Rural Bolivian altiplano homesteads, primarily reliant on agropastoralism, scattered throughout the countryside surrounding a main town (altitude 3800 m; 17°14'S, 65°55'W; darkness duration 10-12 hours over the year).

PARTICIPANTS

One hundred eighty-four co-sleeping mother-infant pairs (infant age 22-730 days).

MEASUREMENTS

Breastfeeding frequency, and retiring and rising times for 885 48-hour observation periods.

RESULTS

Maternal sleep duration covaried with darkness duration. Sleep duration was shorter in those with access to electricity (ie, living nearer to town) than those without access (more distant homesteads). Night breastfeeding rate was fairly steady until it began to decline after the first year postpartum. At a given infant age, higher night breastfeeding rates were associated with less maternal sleep. As their infants aged, mothers without electricity slept more, whereas mothers with access slept less.

CONCLUSIONS

During the first year postpartum, more frequent night nursing shortens maternal sleep more than any other predictor variable. For older infants, the effect of night nursing diminishes, and even modest "modernization" (eg, access to electricity) is associated with shorter maternal sleep.

Estimating sleep parameters using an accelerometer without sleep diary

Wrist worn raw-data accelerometers are used increasingly in large-scale population research. We examined whether sleep parameters can be estimated from these data in the absence of sleep diaries. Our heuristic algorithm uses the variance in estimated z-axis angle and makes basic assumptions about sleep interruptions. Detected sleep period time window (SPT-window) was compared against sleep diary in 3752 participants (range = 60-82 years) and polysomnography in sleep clinic patients (N = 28) and in healthy good sleepers (N = 22). The SPT-window derived from the algorithm was 10.9 and 2.9 minutes longer compared with sleep diary in men and women, respectively. Mean C-statistic to detect the SPT-window compared to polysomnography was 0.86 and 0.83 in clinic-based and healthy sleepers, respectively. We demonstrated the accuracy of our algorithm to detect the SPT-window. The value of this algorithm lies in studies such as UK Biobank where a sleep diary was not used.

Self-Reported Sleep Duration and Quality and Cardiovascular Disease and Mortality: A Dose-Response Meta-Analysis

Background There is growing evidence that sleep duration and quality may be associated with cardiovascular harm and mortality. Methods and Results We conducted a systematic review, meta-analysis, and spline analysis of prospective cohort studies that evaluate the association between sleep duration and quality and cardiovascular outcomes. We searched MEDLINE and EMBASE for these studies and extracted data from identified studies. We utilized linear and nonlinear dose-response meta-analysis models and used DerSimonian-Laird random-effects meta-analysis models of risk ratios, with inverse variance weighting, and the I2 statistic to quantify heterogeneity. Seventy-four studies including 3 340 684 participants with 242 240 deaths among 2 564 029 participants who reported death events were reviewed. Findings were broadly similar across both linear and nonlinear dose-response models in 30 studies with >1 000 000 participants, and we report results from the linear model. Self-reported duration of sleep >8 hours was associated with a moderate increased risk of all-cause mortality, with risk ratio , 1.14 (1.05-1.25) for 9 hours, risk ratio, 1.30 (1.19-1.42) for 10 hours, and risk ratio, 1.47 (1.33-1.64) for 11 hours. No significant difference was identified for periods of self-reported sleep <7 hours, whereas similar patterns were observed for stroke and cardiovascular disease mortality. Subjective poor sleep quality was associated with coronary heart disease (risk ratio , 1.44; 95% confidence interval, 1.09-1.90), but no difference in mortality and other outcomes. Conclusions Divergence from the recommended 7 to 8 hours of sleep is associated with a higher risk of mortality and cardiovascular events. Longer duration of sleep may be more associated with adverse outcomes compared with shorter sleep durations.

Actigraph measures of sleep among female hospital employees working day or alternating day and night shifts

Sleep disturbance is common among shift workers, and may be an important factor in the effect of shift work on chronic disease development. In this cross-sectional study, we described sleep patterns of 294 female hospital workers (142 alternating day-night shift workers, 152 day workers) and determined associations between shift work and sleep duration. Rest-activity cycles were recorded with the ActiGraph GT3X+ for 1 week. Analyses were stratified by chronotype of shift workers. Using all study days to calculate average sleep duration, shift workers slept approximately 13 min less than day workers during main sleep periods, while 24-h sleep duration did not differ between day workers and shift workers. Results from age-adjusted models demonstrated that all shift workers, regardless of chronotype, slept 20-30 min less than day workers on day shifts during main and total sleep. Early and intermediate chronotypes working night shifts slept between 114 and 125 min less than day workers, both with regard to the main sleep episode and 24-h sleep duration, while the difference was less pronounced among late chronotypes. When sleep duration on free days was compared between shift workers and day workers, only shift workers with late chronotypes slept less, by approximately 50 min, than day workers during main sleep. Results from this study demonstrate how an alternating day-night shift work schedule impacts sleep negatively among female hospital workers, and the importance of considering chronotype in sleep research among shift workers.

Relationships Between Training Load, Sleep Duration, and Daily Well-Being and Recovery Measures in Youth Athletes

PURPOSE

To assess the relationships between training load, sleep duration, and 3 daily well-being, recovery, and fatigue measures in youth athletes.

METHODS

Fifty-two youth athletes completed 3 maximal countermovement jumps (CMJs), a daily well-being questionnaire (DWB), the perceived recovery status scale (PRS), and provided details on their previous day's training loads (training) and self-reported sleep duration (sleep) on 4 weekdays over a 7-week period. Partial correlations, linear mixed models, and magnitude-based inferences were used to assess the relationships between the predictor variables (training and sleep) and the dependent variables (CMJ, DWB, and PRS).

RESULTS

There was no relationship between CMJ and training (r = -.09; ±.06) or sleep (r = .01; ±.06). The DWB was correlated with sleep (r = .28; ±.05, small), but not training (r = -.05; ±.06). The PRS was correlated with training (r = -.23; ±.05, small), but not sleep (r = .12; ±.06). The DWB was sensitive to low sleep (d = -0.33; ±0.11) relative to moderate; PRS was sensitive to high (d = -0.36; ±0.11) and low (d = 0.29; ±0.17) training relative to moderate.

CONCLUSIONS

The PRS is a simple tool to monitor the training response, but DWB may provide a greater understanding of the athlete's overall well-being. The CMJ was not associated with the training or sleep response in this population.

Sleep duration and the risk of osteoporosis among middle-aged and elderly adults: a dose-response meta-analysis

It remains unclear how many hours of sleep are associated with the lowest risk of osteoporosis. This meta-analysis was performed to assess the dose-response relationship between sleep duration and risk of osteoporosis. PubMed and Web of Science were searched from inception to December 3, 2017, supplemented by manual searches of the bibliographies of retrieved articles. Data were pooled using fixed- and random-effects models. Restricted cubic spline analysis with four knots was used to model the sleep duration and osteoporosis association. Four cross-sectional studies with eight records were eligible for inclusion in the meta-analysis. A U-shaped dose-response relationship was observed between sleep duration and risk of osteoporosis, with the lowest risk observed at a sleep duration category of 8-9 h per day. Compared with 8-h sleep duration per day, the pooled odds ratio for osteoporosis were 1.03 (95% CI 1.01-1.06) for each 1-h reduction among individuals with shorter sleep duration and 1.01 (95% CI 1.00-1.02) for each 1-h increment among individuals with longer sleep duration. Our dose-response meta-analysis shows a U-shaped relationship between sleep duration and risk of osteoporosis, with the lowest osteoporosis risk at about 8 h per day of sleep duration. Both short and long sleep duration is associated with a significantly increased risk of osteoporosis in the middle-aged and elderly adults, appropriate sleep duration could help for delay or prevention of osteoporosis.

Agreement between self-reported and objectively measured sleep duration among white, black, Hispanic, and Chinese adults in the United States: Multi-Ethnic Study of Atherosclerosis

Study Objectives

To identify systematic biases across groups in objectively and subjectively measured sleep duration.

Methods

We investigated concordance of self-reported habitual sleep duration compared with actigraphy- and single-night in-home polysomnography (PSG) across white, black, Hispanic, and Chinese participants in the Multi-Ethnic Study of Atherosclerosis.

Results

Among 1910 adults, self-reported sleep duration, determined by differences between bed and wake times, was overestimated in all racial groups compared with PSG and actigraphy. Compared with whites (ρ = 0.45), correlations were significantly lower only in blacks (ρ = 0.28). Self-reporting bias for total sleep time compared with wrist actigraphy was 66 min (95% confidence interval [CI]: 61-71) for whites, 58 min (95% CI: 48-69) for blacks, 66 min (95% CI: 57-74) for Hispanics, and 60 min (95% CI: 49-70) for Chinese adults. Compared with PSG, self-reporting bias in whites at 73 min (95% CI: 67-79) was higher than in blacks (54 min [95% CI: 42-65]) and Chinese (49 min [95% CI: 37-61]) but not different from Hispanics (67 min [95% CI: 56-78]). Slight agreement/concordance was observed between self-reported and actigraphy-based total sleep time (kw = 0.14 for whites, 0.10 for blacks, 0.17 for Hispanics, and 0.11 for Chinese) and PSG (kw = 0.08 for whites, 0.04 for blacks, 0.05 for Hispanics, and 0.01 for Chinese) across race/ethnicity.

Conclusions

Self-reported sleep duration overestimated objectively measured sleep across all races, and compared with PSG, overestimation is significantly greater in whites compared with blacks. Larger reporting bias reduces the ability to identify significant associations between sleep duration and health among blacks compared with whites. Sleep measurement property differences should be considered when comparing sleep indices across racial/ethnic groups.

Association between the Munich Chronotype Questionnaire and Wrist Actigraphy

Chronotype refers to individuals' preferences for timing of sleep and wakefulness. It can be quantified by measuring the midpoint time between the start and end of sleep during free days. Measuring chronotype is helpful to diagnose circadian rhythm sleep-wake disorders. The Munich Chronotype Questionnaire (MCTQ) is a self-reported measure of chronotype that calculates the midpoint of sleep on free days based on self-reported bed and wake times. Self-reports of sleep are prone to bias. The objective was to examine the agreement between the MCTQ-derived midpoint and an objective measure obtained using wrist actigraphy. The sleep of 115 participants aged 18–34 (mean = 24, SD = 4.6) was monitored with actigraphy for 4 to 6 consecutive nights. The corrected midpoint of sleep on free days was derived from sleep start and end times on both free days and scheduled days. The corrected midpoint of sleep on free days as measured by the MCTQ was 4:56 (SD = 1 : 16) and by actigraphy was 4:51 (SD = 1 : 23). They were not significantly different (t₍₈₇₎ = 0.66, p = 0.51). A strong correlation was found between these two measurements (r₍₈₈₎ = 0.73, p < 0.001). The 95% limits of agreement were between −1:37:19 and 2:14:38. MCTQ and actigraphy provide similar results for the corrected midpoint of sleep on free days.

Sleep Duration in Relation to Attention Deficit Hyperactivity Disorder in American Adults

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition being diagnosed in increasing numbers. While the link between sleep and ADHD is of increasing interest, the relationship between sleep duration and ADHD remains largely uninvestigated in adult populations. We evaluated the association between self-reported sleep duration and ADHD in a cohort of American adults using data from the 2012 National Health Interview Survey (Centers for Disease Control and Prevention, 2012). Of the 30,858 participants eligible for our analyses, there were 1,122 cases of ADHD. Elevated and diminished sleep durations were both associated with increased odds of reporting ADHD (≤ 6 hr: OR = 1.50, 95% CI 1.19, 1.90; ≥ 9 hr: OR = 1.49, 95% CI 1.26, 1.75) in fully adjusted models. Future prospective studies are necessary to further examine this association in adult patients.

Exploring the mechanisms of the racial disparity in drowsy driving

OBJECTIVE

Drowsy driving is a significant cause of traffic accidents and fatalities. Although previous reports have shown an association between race and drowsy driving, the reasons for this disparity remain unclear.

STUDY DESIGN

A cross-sectional analysis of responses from 193,776 White, Black, and Hispanic adults participating in the US Behavioral Risk Factor Surveillance System from 2009 to 2012 who answered a question about drowsy driving.

MEASUREMENTS

Drowsy driving was defined as self-reporting an episode of falling asleep while driving in the past 30 days. All analyses were adjusted for age, sex, and medical comorbidities. Subsequent modeling evaluated the impact of accounting for differences in health care access, alcohol consumption, risk-taking behaviors, and sleep quality on the race-drowsy driving relationship.

RESULTS

After adjusting for age, sex, and medical comorbidities, the odds ratio (OR) for drowsy driving was 2.07 (95% confidence interval [CI] 1.69-2.53) in Blacks and 1.80 (95% CI 1.51-2.15) in Hispanics relative to Whites. Accounting for health care access, alcohol use, and risk-taking behaviors had little effect on these associations. Accounting for differences in sleep quality resulted in a modest reduction in the OR for drowsy driving in Blacks (OR = 1.55, 95% CI 1.27-1.89) but not Hispanics (OR = 1.74, 95% CI 1.45-2.08).

CONCLUSION

US Blacks and Hispanics have approximately twice the risk of drowsy driving compared to whites. Differences in sleep quality explained some of this disparity in Blacks but not in Hispanics. Further research to understand the root causes of these disparities is needed.

Monitoring healthy and disturbed sleep through smartphone applications: a review of experimental evidence

Smartphone applications are considered as the prime candidate for the purposes of large-scale, low-cost and long-term sleep monitoring. How reliable and scientifically grounded is smartphone-based assessment of healthy and disturbed sleep remains a key issue in this direction. Here we offer a review of validation studies of sleep applications to the aim of providing some guidance in terms of their reliability to assess sleep in healthy and clinical populations, and stimulating further examination of their potential for clinical use and improved sleep hygiene. Electronic literature review was conducted on Pubmed. Eleven validation studies published since 2012 were identified, evaluating smartphone applications' performance compared to standard methods of sleep assessment in healthy and clinical samples. Studies with healthy populations show that most sleep applications meet or exceed accuracy levels of wrist-based actigraphy in sleep-wake cycle discrimination, whereas performance levels drop in individuals with low sleep efficiency (SE) and in clinical populations, mirroring actigraphy results. Poor correlation with polysomnography (PSG) sleep sub-stages is reported by most accelerometer-based apps. However, multiple parameter-based applications (i.e., EarlySense, SleepAp) showed good capability in detection of sleep-wake stages and sleep-related breathing disorders (SRBD) like obstructive sleep apnea (OSA) respectively with values similar to PSG. While the reviewed evidence suggests a potential role of smartphone sleep applications in pre-screening of SRBD, more experimental studies are warranted to assess their reliability in sleep-wake detection particularly. Apps' utility in post treatment follow-up at home or as an adjunct to the sleep diary in clinical setting is also stressed.

Effects of Insufficient Sleep on Pituitary-Adrenocortical Response to CRH Stimulation in Healthy Men

Study Objectives

Severe sleep restriction results in elevated evening cortisol levels. We examined whether this relative hypercortisolism is associated with alterations in the pituitary-adrenocortical response to evening corticotropin-releasing hormone (CRH) stimulation.

Methods

Eleven subjects participated in 2 sessions (2 nights of 10 hours vs. 4 hours in bed) in randomized order. Sleep was polygraphically recorded. After the second night of each session, blood was sampled at 20-minute intervals from 09:00 to 24:00 for adrenocorticotropic hormone (ACTH) and cortisol measurements, and perceived stress was assessed hourly. Ovine CRH was injected at 18:00 (1 µg/kg body weight).

Results

Prior to CRH injection, baseline ACTH, but not cortisol, levels were elevated after sleep restriction. Relative to the well-rested condition, sleep restriction resulted in a 27% decrease in overall ACTH response to CRH (estimated by the incremental area under the curve from 18:00 to 24:00; p = .002) while the cortisol response was decreased by 21% (p = .083). Further, the magnitude of these decreases was correlated with the individual amount of sleep loss (ACTH: rSp = -0.65, p = .032; cortisol: rSp = -0.71, p = .015). The acute post-CRH increment of cortisol was reduced (p = .002) without changes in ACTH reactivity, suggesting decreased adrenal sensitivity. The rate of decline from peak post-injection levels was reduced for cortisol (p = .032), but not for ACTH. Scores of perceived stress were unaffected by CRH injection and were low and similar under both sleep conditions.

Conclusions

Sleep restriction is associated with a reduction of the overall ACTH and cortisol responses to evening CRH stimulation, and a reduced reactivity and slower recovery of the cortisol response.

Household Food Insecurity and Sleep Patterns Among Mexican Adults: Results from ENSANUT-2012

To examine the independent association of household food insecurity with sleep duration and quality in a nationally representative survey of adults in Mexico. The Latin American and Caribbean Food Security Scale was used to categorize households as secure, mild (43.7 %), moderate (19.0 %), or severe (11.8 %). We assessed the association between household food insecurity and self-reported sleep duration and quality among 11,356 adults using weighted multinomial and binomial logistic regression. After adjusting for potential confounders, a significant association was found between severe household food insecurity and getting less than the recommended 7-8 h of sleep [adjusted odds ratio (AOR) =1.83, 95 % confidence interval (CI) =1.37-2.43]. Compared with food-secure households, odds of poor sleep quality increased with level of severity (AOR = 1.27, 95 % CI 1.04-1.56 for mild; AOR = 1.71, 95 % CI 1.36-2.14 for moderate; and AOR = 1.89, 95 % CI 1.45-2.45 for severe household food insecurity). Household food insecurity is associated with inadequate sleep duration and poor sleep quality among Mexican adults. This study underscores the adverse effects of household food insecurity on the well-being of vulnerable populations.

Prevalence and social and health correlates of insomnia symptoms among middle- and older-age persons in rural South Africa

This study investigated the prevalence and social and health correlates of insomnia symptoms among middle- and older-adults in rural South Africa. We analysed baseline survey data from the Health and Aging in Africa: A Longitudinal Study of an INDEPTH community in South Africa (HAALSI) (N = 5 059; females = 53.6%; largely African Shangaan/Tsonga-speaking). In all, 8.0% of the adults had three insomnia symptoms, 8.9% of participants had difficulty initiating sleep, 13.6% had difficulty in sleep maintenance, and 6.5% had poor sleep quality. In adjusted logistic regression, lower education, perceived unsafe neighbourhood, poorer self-rated health status, vision difficulty, pain, depressive symptoms, and posttraumatic stress disorder (PTSD) symptoms increased the odds of having insomnia symptoms. Insomnia symptoms are common in middle- and older-age adults in rural South Africa, and various risk factors were identified. This can help in improving insomnia prevention treatment in this population.

Sleep Quantity and Quality of Ontario Wildland Firefighters Across a Low-Hazard Fire Season

OBJECTIVE

The aim of the study was to assess the sleep quality, quantity, and fatigue levels of Canadian wildland firefighters while on deployment.

METHODS

Objective and subjective sleep and fatigue measures were collected using actigraphy and questionnaires during non-fire (Base) and fire (Initial Attack and Project) deployments.

RESULTS

Suboptimal sleep quality and quantity were more frequently observed during high-intensity, Initial Attack fire deployments. Suboptimal sleep was also exhibited during non-fire (Base) work periods, which increases the risk of prefire deployment sleep debt. Self-reported, morning fatigue scores were low-to-moderate and highest for Initial Attack fire deployments.

CONCLUSIONS

The study highlights the incidence of suboptimal sleep patterns in wildland firefighters during non-fire and fire suppression work periods. These results have implications for the health and safety practices of firefighters given the link between sleep and fatigue, in a characteristically hazardous occupation.

Systematic review of the relationships between sleep duration and health indicators in the early years (0-4 years)

Background

The objective of this systematic review was to examine for the first time the associations between sleep duration and a broad range of health indicators in children aged 0 to 4 years.

Methods

Electronic databases were searched with no limits on date or study design. Included studies (published in English or French) were peer-reviewed and met the a priori determined population (apparently healthy children aged 1 month to 4.99 years), intervention/exposure/comparator (various sleep durations), and outcome criteria (adiposity, emotional regulation, cognitive development, motor development, growth, cardiometabolic health, sedentary behaviour, physical activity, quality of life/well-being, and risks/injuries). The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. Due to high levels of heterogeneity across studies, narrative syntheses were employed.

Results

A total of 69 articles/studies (62 unique samples) met inclusion criteria. Data across studies included 148,524 unique participants from 23 countries. The study designs were randomized trials (n = 3), non-randomized interventions (n = 1), longitudinal studies (n = 16), cross-sectional studies (n = 42), or longitudinal studies that also reported cross-sectional analyses (n = 7). Sleep duration was assessed by parental report in 70% of studies (n = 48) and was measured objectively (or both objectively and subjectively) in 30% of studies (n = 21). Overall, shorter sleep duration was associated with higher adiposity (20/31 studies), poorer emotional regulation (13/25 studies), impaired growth (2/2 studies), more screen time (5/5 studies), and higher risk of injuries (2/3 studies). The evidence related to cognitive development, motor development, physical activity, and quality of life/well-being was less clear, with no indicator showing consistent associations. No studies examined the association between sleep duration and cardiometabolic biomarkers in children aged 0 to 4 years. The quality of evidence ranged from “very low” to “high” across study designs and health indicators.

Conclusions

Despite important limitations in the available evidence, longer sleep duration was generally associated with better body composition, emotional regulation, and growth in children aged 0 to 4 years. Shorter sleep duration was also associated with longer screen time use and more injuries. Better-quality studies with stronger research designs that can provide information on dose-response relationships are needed to inform contemporary sleep duration recommendations.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4850-2) contains supplementary material, which is available to authorized users.

Sleep During Pregnancy: The nuMoM2b Pregnancy and Sleep Duration and Continuity Study

Study Objectives

To characterize sleep duration, timing and continuity measures in pregnancy and their association with key demographic variables.

Methods

Multisite prospective cohort study. Women enrolled in the nuMoM2b study (nulliparous women with a singleton gestation) were recruited at the second study visit (16-21 weeks of gestation) to participate in the Sleep Duration and Continuity substudy. Women <18 years of age or with pregestational diabetes or chronic hypertension were excluded from participation. Women wore a wrist activity monitor and completed a sleep log for 7 consecutive days. Time in bed, sleep duration, fragmentation index, sleep efficiency, wake after sleep onset, and sleep midpoint were averaged across valid primary sleep periods for each participant.

Results

Valid data were available from 782 women with mean age of 27.3 (5.5) years. Median sleep duration was 7.4 hours. Approximately 27.9% of women had a sleep duration of <7 hours; 2.6% had a sleep duration of >9 hours. In multivariable models including age, race/ethnicity, body mass index, insurance status, and recent smoking history, sleep duration was significantly associated with race/ethnicity and insurance status, while time in bed was only associated with insurance status. Sleep continuity measures and sleep midpoint were significantly associated with all covariates in the model, with the exception of age for fragmentation index and smoking for wake after sleep onset.

Conclusions

Our results demonstrate the relationship between sleep and important demographic characteristics during pregnancy.

Long-Term Sleep Duration as a Risk Factor for Breast Cancer: Evidence from a Systematic Review and Dose-Response Meta-Analysis

Sleep patterns have been associated with the development of cancers, although the association between sleep duration and breast cancer remains controversial. The purpose of our study was to explore the relationship between sleep duration and breast cancer risk. The PubMed and Web of Science databases were searched, and restricted cubic splines were used to explore the dose-response relationship. Data from 415,865 participants were derived from 10 studies. A J-shaped nonlinear trend was found between sleep duration and breast cancer incidence (Pnon-linear = 0.012); compared with the reference hours (6 h or 7 h), with increasing sleep hours, the risk of breast cancer increased (Ptrend = 0.028). Moreover, a nonlinear relationship was found between sleep duration and estrogen receptor-positive breast cancer (Pnon-linear = 0.013); the risk of estrogen receptor-positive breast cancer increased with increasing sleep hours compared to the reference hours (Ptrend = 0.024). However, no nonlinear relationship was found between sleep duration and estrogen receptor-negative breast cancer; the risk of estrogen receptor-negative breast cancer was 1.035 for every additional sleep hour. Compared to women with the reference number of sleep hours, women with a longer sleep duration might have a significantly increased risk of breast cancer, especially estrogen receptor-positive breast cancer.

Actigraphic Sleep Patterns of U.S. Hispanics: The Hispanic Community Health Study/Study of Latinos

Study objective

To assess the extent to which objective sleep patterns vary among U.S. Hispanics/Latinos.

Methods

We assessed objective sleep patterns in 2087 participants of the Hispanic Community Health Study/Study of Latinos from 6 Hispanic/Latino subgroups aged 18-64 years who underwent 7 days of wrist actigraphy.

Results

The age- and sex-standardized mean (SE) sleep duration was 6.82 (0.05), 6.72 (0.07), 6.61 (0.07), 6.59 (0.06), 6.57 (0.10), and 6.44 (0.09) hr among individuals of Mexican, Cuban, Dominican, Central American, Puerto Rican, and South American heritage, respectively. Sleep maintenance efficiency ranged from 89.2 (0.2)% in Mexicans to 86.5 (0.4)% in Puerto Ricans, while the sleep fragmentation index ranged from 19.7 (0.3)% in Mexicans to 24.2 (0.7)% in Puerto Ricans. In multivariable models adjusted for age, sex, season, socioeconomic status, lifestyle habits, and comorbidities, these differences persisted.

Conclusions

There are important differences in actigraphically measured sleep across U.S. Hispanic/Latino heritages. Individuals of Mexican heritage have longer and more consolidated sleep, while those of Puerto Rican heritage have shorter and more fragmented sleep. These differences may have clinically important effects on health outcomes.

Estimating sleep efficiency in 10- to- 13-year-olds using a waist-worn accelerometer

OBJECTIVE

In field settings, wrist- and waist-worn accelerometers are typically used to assess sleep characteristics and movement behaviors, respectively. There has been a shift in movement behavior studies to wear accelerometers 24 h/d. Sleep characteristics could be assessed in these studies if sleep algorithms were available for waist-worn accelerometers. The objective of this study was to develop and provide validity data for an algorithm/sleep likelihood score cut-off to estimate sleep efficiency in children using the waist-worn Actical accelerometer.

DESIGN

Cross-sectional study.

PARTICIPANTS

Fifty healthy children aged 10-13 years.

MEASUREMENTS

Children wore an Actical on their waist and an Actiwatch 2 on their nondominant wrist for 8 nights at home in their normal sleep environment. Participants were randomized into algorithm/sleep likelihood score "development" and "test" groups (n=25 per group). Within the development group, we assessed sleep efficiency with the Actical using the same algorithm that the Actiwatch 2 uses and selected the sleep likelihood score cut-off value that was the most accurate at predicting sleep efficiency at the nightly level compared with the Actiwatch 2. We applied this algorithm and cut-off value to the test group.

RESULTS

Mean (SD) sleep efficiency estimates for the test group from the Actical and Actiwatch 2 were 89.0% (3.9%) and 88.7% (3.1%), respectively. Bland-Altman plots and absolute difference scores revealed considerable agreement between devices for both nightly and weekly estimates of sleep efficiency.

CONCLUSION

A waist-worn Actical accelerometer can accurately predict sleep efficiency in field settings among healthy 10- to 13-year-olds.

Past, present, and future: trends in sleep duration and implications for public health

Sleep is important for the physical, social and mental well-being of both children and adults. Over the years, there has been a general presumption that sleep will inevitably decline with the increase in technology and a busy 24-hour modern lifestyle. This narrative review discusses the empirical evidence for secular trends in sleep duration and the implications of these trends.

Sleep duration as a mediator between an alternating day and night shift work schedule and metabolic syndrome among female hospital employees

Objectives

The main objective was to determine whether sleep duration on work shifts mediates the relationship between a current alternating day and night shift work schedule and metabolic syndrome among female hospital employees. The secondary objective was to assess whether cumulative lifetime shift work exposure was associated with metabolic syndrome.

Methods

In this cross-sectional study of 294 female hospital employees, sleep duration was measured with the ActiGraph GT3X+. Shift work status was determined through self-report. Investigation of the total, direct and indirect effects between shift work, sleep duration on work shifts and metabolic syndrome was conducted using regression path analysis. Logistic regression was used to determine the association between cumulative shift work exposure and metabolic syndrome.

Results

Shift work is strongly associated with metabolic syndrome (ORTotal=2.72, 95% CI 1.38 to 5.36), and the relationship is attenuated when work shift sleep duration is added to the model (ORDirect=1.18, 95% CI 0.49 to 2.89). Sleep duration is an important intermediate between shift work and metabolic syndrome (ORIndirect=2.25, 95% CI 1.27 to 4.26). Cumulative shift work exposure is not associated with metabolic syndrome in this population.

Conclusions

Sleep duration mediates the association between a current alternating day–night shift work pattern and metabolic syndrome.

Sleep characteristics, light at night and breast cancer risk in a prospective cohort

Increasing numbers of women in the US are getting too little sleep. Inadequate sleep has been associated with impaired metabolic function and endocrine disruption. Sister Study cohort participants (n = 50,884), completed baseline and follow-up questionnaires on sleep patterns. Incident breast cancers estrogen receptor (ER) status of the tumor were ascertained from questionnaires and medical records. Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs). Analyses of sleep characteristics reported at the first follow-up interview included only participants who were breast cancer-free at time of follow-up interview. Over ∼7 years of follow-up, 2,736 breast cancer cases (invasive and ductal carcinoma in situ) were diagnosed. There was little evidence that usual sleep duration or other sleep characteristics were associated with breast cancer. However, relative to those with no difficulty sleeping, women who reported having difficulty sleeping ≥ 4 nights a week were at an increased risk of overall (HR = 1.32, 95% CI: 1.09-1.61) and postmenopausal breast cancer (HR = 1.51, 95% CI 1.24-1.85). Risk of ER+ invasive cancer was elevated for women who reported having a light or television on in the room while sleeping (HR = 1.20, 95% CI: 0.97-1.47) or who typically got less sleep than they needed to feel their best (HR = 1.21, 95% CI: 0.98-1.50). In our study, most sleep characteristics, including sleep duration, were not associated with an increased risk although higher risk was observed for some markers of inadequate or poor quality sleep.

Sleep duration trends and trajectories among youth in the COMPASS study

OBJECTIVES

Limited Canadian studies have examined youth sleep over time. This study explored sleep duration over recent years among youth, patterns over the course of secondary school, and subgroups at greater risk of sleep deprivation and problematic trajectories.

DESIGN

Longitudinal survey.

PARTICIPANTS/SETTING

Secondary school students in Ontario and Alberta, Canada.

MEASURES AND ANALYSES

In cross-sectional analyses, student-reported sleep duration was analyzed in three waves of the COMPASS study (Y₂: 2013/2014, Y₃: 2014/2015, Y₄: 2015/2016), and differences by student-level (race/ethnicity, grade, sex) and school-level (urbanicity, median household income) variables were tested in the most recent wave. For the longitudinal analyses, group-based trajectory modeling was conducted using 3-year linked data, adding risk factors as predictors of problematic trajectories.

RESULTS

Average sleep durations declined over the 3 study waves, resulting in less than half of youth meeting the guideline of 8-10 hours per night. Four trajectory groups comprised almost 90% of participants, with 8.8% of students classified as long sleepers, whereas more than one-third of students belonged to 2 sleep-deprived trajectory groups (short [9.3%] and low-normal [26.7%]). In both the cross-sectional and longitudinal analyses, longer sleep durations were more likely among students who identified as male, White, in earlier grades, and attending schools in areas with higher median household income and classified as rural/small urban, relative to their counterparts.

CONCLUSIONS

Results support the necessity of continued surveillance and interventions to monitor and counteract what appears to be an ongoing trend of diminishing sleep and a growing number of sleep-deprived adolescents. Targeted efforts in less affluent and more metropolitan areas warrant consideration.

Subjective and objective sleep quality modulate emotion regulatory brain function in anxiety and depression

BACKGROUND

Disturbances in emotion regulation and sleep are shared across anxiety and mood disorders. Poor sleep has been shown to impair cognitive processes which may undermine cognitive regulatory function. However, it remains unknown if sleep quality impacts regulatory mechanisms in clinical anxiety and depression.

METHODS

During fMRI, 78 patients with social anxiety disorder, generalized anxiety disorder, and/or major depressive disorder completed a validated emotion regulation task, which involved reappraisal (i.e., decrease negative affect) as compared to viewing aversive images. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and actigraphy, representing subjective and objective measures of sleep, respectively. Regression analysis was conducted with the PSQI and actigraphy sleep efficiency, duration, and wake-after sleep onset variables.

RESULTS

PSQI and actigraphy measures indicated that the majority of patients experienced problematic sleep, however, subjective and objective sleep measures were uncorrelated. Whole-brain voxel-wise regression analysis, controlling for diagnosis, revealed worse self-reported sleep corresponded with less reappraise-related activation in the dorsal anterior cingulate cortex (DACC). The same analysis performed with actigraphy data showed less sleep efficiency positively corresponded with DACC activation. Post-hoc stepwise regression analysis showed these sleep measures predicted DACC activity whereas anxiety and depression symptoms did not.

CONCLUSIONS

Individual differences in self-perceived and objective sleep quality differentially modulated the DACC, which is implicated in cognitive reappraisal. Findings suggest neural correlates of emotion regulation tracks different aspects of the sleep experience. Results also indicate sleep disturbance may play a role in the emotion dysregulation observed in anxiety and depressive disorders.

Comprehensive assessments of long-term sleep habits in epidemiological study: Validity and reliability of sleep factors questionnaire (SFQ) among Chinese women

OBJECTIVE

Epidemiological studies suggested that poor sleep is a potentially novel risk factor for several health outcomes currently; however, there are no validated questionnaires that can systematically measure sleep parameters within these studies. We evaluated the reliability and validity of 17-item sleep factors questionnaire (SFQ), which was developed to comprehensively assess long-term sleep habits for the Jiujiang Breast Cancer Study (JBCS), Jiujiang, China.

METHODS

The participants included 100 women aged 18-74years, who were randomly selected from the JBCS project, and completed a SFQ at baseline and again 1year later, and 4 quarterly 30 consecutive days (a total of 120days) sleep diaries over this same year. Reliability was tested by comparing the 2 SFQs; validity by comparing the average measures between the SFQ and the 4 sleep diaries.

RESULTS

Validity analysis showed moderate correlation (γ=0.41) for sleep duration with the adjusted concordance correlation coefficient (CCC_adj) of 0.54; the weighted κ statistics indicated an excellent agreement for night/shift work and sleep medication use; fair-to-moderate for sleep quality, light at night (LAN), nighttime sleeping with light on, sleep noise and nap time; slight-to-fair for sleep quality and nighttime wakings frequency. Reliability analysis showed excellent correlation for night/shift work and sleep medication use; fair-to-moderate for LAN, nighttime wakings frequency, insomnia frequency, sleep noise and nap time; but slight-to-fair for insomnia frequency and nighttime sleeping with light on; the CCC_adj for sleep duration was 0.61.

CONCLUSIONS

The SFQ showed reasonable reliability and validity for sleep assessments in most domains.

Interactions between sleep, movement and other non-movement behaviours in the pathogenesis of childhood obesity

Research examining the health effects of physical activity, sedentary behaviour and sleep on different health outcomes has largely been conducted independently or in isolation of the other behaviours. However, the fact that time is finite (i.e. 24 h) suggests that the debate on whether or not the influence of a single behaviour is independent of another one is conceptually incorrect. Time spent in one behaviour should naturally depend on the composition of the rest of the day. Recent evidence using more appropriate analytical approaches to deal with this methodological issue shows that the combination of sleep, movement and non-movement behaviours matters and all components of the 24-h movement continuum should be targeted to enhance health and prevent childhood obesity. The objective of this review is to discuss research investigating how combinations of physical activity, sedentary behaviour and sleep are related to childhood obesity. Emerging statistical approaches (e.g. compositional data analysis) that can provide a good understanding of the best 'cocktail' of behaviours associated with lower adiposity and improved health are also discussed. Finally, future research directions are provided. Collectively, it becomes clearer that guidelines and public health interventions should target all movement behaviours synergistically to optimize health of children and youth around the world.

Systematic review of the relationships between sleep duration and health indicators in school-aged children and youth

The objective of this systematic review was to examine the relationships between objectively and subjectively measured sleep duration and various health indicators in children and youth aged 5-17 years. Online databases were searched in January 2015 with no date or study design limits. Included studies were peer-reviewed and met the a priori-determined population (apparently healthy children and youth aged 5-17 years), intervention/exposure/comparator (various sleep durations), and outcome (adiposity, emotional regulation, cognition/academic achievement, quality of life/well-being, harms/injuries, and cardiometabolic biomarkers) criteria. Because of high levels of heterogeneity across studies, narrative syntheses were employed. A total of 141 articles (110 unique samples), including 592 215 unique participants from 40 different countries, met inclusion criteria. Overall, longer sleep duration was associated with lower adiposity indicators, better emotional regulation, better academic achievement, and better quality of life/well-being. The evidence was mixed and/or limited for the association between sleep duration and cognition, harms/injuries, and cardiometabolic biomarkers. The quality of evidence ranged from very low to high across study designs and health indicators. In conclusion, we confirmed previous investigations showing that shorter sleep duration is associated with adverse physical and mental health outcomes. However, the available evidence relies heavily on cross-sectional studies using self-reported sleep. To better inform contemporary sleep recommendations, there is a need for sleep restriction/extension interventions that examine the changes in different outcome measures against various amounts of objectively measured sleep to have a better sense of dose-response relationships.

Reliability of Actigraphy and Subjective Sleep Measurements in Adults: The Design of Sleep Assessments

STUDY OBJECTIVES

The aim of the study was to investigate how many nights of measurement are needed for a reliable measure of sleep in a working population including adult women and men.

METHODS

In all, 54 individuals participated in the study. Sleep was assessed for 7 consecutive nights using actigraphy as an objective measure, and the Karolinska sleep diary for a subjective measure of quality. Using intra-class correlation and the Spearman-Brown formula, calculations of how many nights of measurements were required for a reliable measure were performed. Differences in reliability according to whether or not weekend measurements were included were investigated. Further, the correlation between objectively (actigraphy) measured sleep and subjectively measured sleep quality was studied over the different days of the week.

RESULTS/CONCLUSIONS

The results concerning actigraphy sleep measures suggest that data from at least 2 nights are to be recommended when assessing sleep percent and at least 5 nights when assessing sleep efficiency. For actigraphy-measured total sleep time, more than 7 nights are needed. At least 6 nights of measurements are required for a reliable measure of self-reported sleep. Fewer nights (days) are required if measurements include only week nights. Overall, there was a low correlation between the investigated actigraphy sleep parameters and subjective sleep quality, suggesting that the two methods of measurement capture different dimensions of sleep.

Associations between actigraphy-assessed sleep, inflammatory markers, and insulin resistance in the Midlife Development in the United States (MIDUS) study

BACKGROUND

Disturbed sleep has been associated with increased insulin resistance and elevated inflammation. Although there is growing body of evidence that activation of inflammatory pathways plays a crucial role in the development of insulin resistance, the mediational model whereby sleep disturbances influence inflammation that drives insulin resistance has not been fully assessed in general population studies with objectively measured sleep. This study aimed to examine associations between objectively measured sleep, inflammatory markers, and insulin resistance simultaneously and in a mediational analysis, thereby offering insights into the possible causal model.

METHODS

Cross-sectional data collected from 2004 to 2009 during the Midlife Development in the United States II biomarker project were used. The study population included 374 community-based participants (138 men and 236 women) who completed seven nights of wrist actigraphy. Multiple regressions controlling for age and statistically significant variables in univariate regressions were performed to evaluate the associations between actigraphy-assessed sleep measures, inflammatory cytokines, and insulin resistance.

RESULTS

The regression models showed that in women, higher sleep onset latency (SOL) was associated with higher insulin resistance after controlling for age, smoking, obesity, diabetes, depression, and inflammatory cytokines. Higher SOL was also associated with higher interleukin (IL)-6 and C-reactive protein (CRP) levels in women, but no association was found in men. Using mediation models in women, the association between SOL and insulin resistance was partially explained by the indirect effect of inflammatory cytokines.

CONCLUSION

A combination of inflammation and other unidentified pathways may contribute to the relationship between disturbed sleep and glucose homeostasis.

Lack of sleep as a contributor to obesity in adolescents: impacts on eating and activity behaviors

Background

Sleep is an important contributor to physical and mental health; however, chronic sleep deprivation has become common in adolescents, especially on weekdays. Adolescents aged 14–17 years are recommended to sleep between 8 and 10 h per night to maximize overall health and well-being. Although sleep needs may vary between individuals, sleep duration recommendations are important for surveillance and help inform policies, interventions, and the population of healthy sleep behaviors. Long sleepers are very rare among teenagers and sleeping too much is not a problem per se; only insufficient sleep is associated with adverse health outcomes in the pediatric population. Causes of insufficient sleep are numerous and chronic sleep deprivation poses a serious threat to the academic success, health and safety of adolescents. This article focuses on the link between insufficient sleep and obesity in adolescents.

Discussion

This “call to action” article argues that sleep should be taken more seriously by the public health community and by our society in general, i.e., given as much attention and resources as nutrition and physical activity. Not only that having a good night’s sleep is as important as eating a healthy diet and being regularly physically active for overall health, but sleeping habits also impact eating and screen time behaviors and, therefore, can influence body weight control.

Summary

Short sleep duration, poor sleep quality, and late bedtimes are all associated with excess food intake, poor diet quality, and obesity in adolescents. Sleep, sedentary behavior, physical activity and diet all interact and influence each other to ultimately impact health. A holistic approach to health (i.e., the whole day matters) targeting all of these behaviors synergistically is needed to optimize the impact of our interventions. Sleep is not a waste of time and sleep hygiene is an important factor to consider in the prevention and treatment of obesity.

Balanced: a randomised trial examining the efficacy of two self-monitoring methods for an app-based multi-behaviour intervention to improve physical activity, sitting and sleep in adults

BACKGROUND

Many adults are insufficiently physically active, have prolonged sedentary behaviour and report poor sleep. These behaviours can be improved by interventions that include education, goal setting, self-monitoring, and feedback strategies. Few interventions have explicitly targeted these behaviours simultaneously or examined the relative efficacy of different self-monitoring methods.

METHODS/DESIGN

This study aims to compare the efficacy of two self-monitoring methods in an app-based multi-behaviour intervention to improve objectively measured physical activity, sedentary, and sleep behaviours, in a 9 week 2-arm randomised trial. Participants will be adults (n = 64) who report being physically inactive, sitting >8 h/day and frequent insufficient sleep (≥14 days out of last 30). The "Balanced" intervention is delivered via a smartphone 'app', and includes education materials (guidelines, strategies to promote change in behaviour), goal setting, self-monitoring and feedback support. Participants will be randomly allocated to either a device-entered or user-entered self-monitoring method. The device-entered group will be provided with a activity tracker to self-monitor behaviours. The user-entered group will recall and manually record behaviours. Assessments will be conducted at 0, 3, 6, and 9 weeks. Physical activity, sedentary behaviour and sleep-wake behaviours will be measured using the wrist worn Geneactiv accelerometer. Linear mixed models will be used to examine differences between groups and over time using an alpha of 0.01.

DISCUSSION

This study will evaluate an app-based multi-behavioural intervention to improve physical activity, sedentary behaviour and sleep; and the relative efficacy of two different approaches to self-monitoring these behaviours. Outcomes will provide information to inform future interventions and self-monitoring targeting these behaviours.

TRIAL REGISTRATION

ACTRN12615000182594 (Australian New Zealand Clinical Trials Registry. Registry URL: www.anzctr.org.au ; registered prospectively on 25 February 2015).

A feasibility study: Use of actigraph to monitor and follow-up sleep/wake patterns in individuals attending community pharmacy with sleeping disorders

Introduction:

Community pharmacists are in a suitable position to give advice and provide appropriate services related to sleep disorders to individuals who are unable to easily access sleep clinics. An intervention with proper objective measure can be used by the pharmacist to assist in consultation.

Objectives:

The study objectives are to evaluate: (1) The effectiveness of a community pharmacy-based intervention in managing sleep disorders and (2) the role of actigraph as an objective measure to monitor and follow-up individuals with sleeping disorders.

Methods and Instruments:

The intervention care group (ICG) completed questionnaires to assess sleep scale scores (Epworth Sleepiness Scale [ESS] and Insomnia Severity Index [ISI]), wore a wrist actigraph, and completed a sleep diary. Sleep parameters (sleep efficiency in percentage [SE%], total sleep time, sleep onset latency, and number of nocturnal awakenings) from actigraphy sleep report were used for consultation and to validate sleep diary. The usual care group (UCG) completed similar questionnaires but received standard care.

Results:

Pre- and post-mean scores for sleep scales and sleep parameters were compared between and within groups. A significant difference was observed when comparing pre- and post-mean scores for ISI in the ICG, but not for ESS. For SE%, an increase was found in the number of subjects rated as “good sleepers” at post-assessment in the ICG.

Conclusions:

ISI scores offer insights into the development of a community pharmacy-based intervention for sleeping disorders, particularly in those with symptoms of insomnia. It also demonstrates that actigraph could provide objective sleep/wake data to assist community pharmacists during the consultation.

Sleep duration estimates of Canadian children and adolescents

The objective of this study was to provide contemporary sleep duration estimates of Canadian school-aged children and adolescents and to determine the proportion adhering to the sleep duration recommendations. This study included 24 896 participants aged 10-17 years from the 2013/2014 Canadian Health Behaviour in School-aged Children study (HBSC), a nationally representative cross-sectional study. Bedtime and wake-up times were reported by participants and their sleep duration was calculated. Participants were then classified as having a sleep duration that met the recommended range (9-11 h per night for 10-13-year-olds or 8-10 h per night for 14-17-year-olds), a sleep duration that was shorter than the recommended range or a sleep duration that was longer than the recommended range. An estimated 68% of children aged 10-13 years and 72% of adolescents aged 14-17 years sleep for the recommended amount per night when averaged across all days of the week. Short sleepers represent 31% of school-aged children and 26% of adolescents. Long sleepers are rare (<2% overall). Children and adolescents sleep ~1 h more at weekends compared to weekdays. Approximately 5% of the participants typically went to bed after midnight on weekdays and 31% did so at weekends; these proportions reached 11 and 45%, respectively, within 16-17-year-olds. In general, differences in sleep times between boys and girls are small and not clinically significant. In conclusion, almost one-third of Canadian children and adolescents sleep less than the recommended amount. Public health efforts should continue to monitor the sleep of Canadian children and adolescents and identify subgroups of the population more likely to be affected by insufficient sleep.