Sleep Duration Variability Research Articles

0242 Intraindividual Variability in Sleep Duration Blunts Response to Academic Stressors

Abstract Introduction Cross-sectional studies indicate that greater intra-individual variability (IIV) in sleep is correlated with poorer cognitive-emotional outcomes. Yet, the causal direction of these relationships is unclear. Therefore, we conducted an experimental study to compare cognitive and stress outcomes following random assignment to normal sleep, sleep restriction, and irregular/IIV sleep conditions. Methods Ninety college students (mean age=19.16, SD=0.98; 77.78% female) completed an Organic Chemistry virtual lecture during session 1. Then, for the next five days, participants were randomly assigned to the following conditions: normal sleep (8h in bed every night), sleep restriction (6h in bed every night), or IIV sleep (nightly oscillation between 6.5h and 9.5h in bed, with mean of 8h/night). Adherence was confirmed using actigraphy. On the sixth day (session 2), participants took a test on the Organic Chemistry lecture (retention measure) and then completed a new lecture and test (acquisition measure). Participants reported their stress levels across the lectures and tests. Results ANCOVA tests showed that sleep condition did not affect retention (F=0.50, p=.611) or acquisition of Organic Chemistry knowledge (F=1.33, p=.275; adjusted for Grade Point Average). Interestingly, participants in the IIV condition reported lower stress levels throughout session 2 than students in the normal sleep condition, adjusting for baseline stress levels (p=.025). Furthermore, when collapsing across conditions, correlation analyses confirmed that greater IIV in TST predicted lower stress throughout session 2, after adjusting for mean TST and baseline stress level (r=-.33, p=.014). This “blunted” stress response following nightly sleep fluctuations was in contrast to the heightened stress levels that were associated with shorter mean TST (r=-.22, p=.051). Conclusion Brief sleep variability and mild sleep restriction had minimal impact on laboratory measures of STEM knowledge retention and acquisition. However, greater sleep IIV blunted reactivity to academic stressors, which may reflect altered hypothalamic–pituitary–adrenal axis functions and have implications for student metacognition and course persistence. Future research should investigate the chronic effect of maintaining irregular sleep patterns and whether improving regularity of sleep across longer time intervals promotes cognitive and emotional functioning. Support (If Any) American Psychological Association, APAGS, Psi Chi, National Science Foundation (1920730, 1943323)

0184 Too Jittery to Sleep? Temporal Associations of Actigraphic Sleep and Caffeine in Adolescents

Abstract Introduction The majority of adolescents report consuming a caffeinated beverage on a typical day, which has been linked to poor sleep health in cross-sectional studies. However, it is unknown whether poor sleep predicts caffeine consumption, and/or whether caffeine consumption predicts poor sleep, particularly when sleep is measured objectively. The current study examined within- and between-person associations of actigraphic sleep dimensions with caffeinated beverage consumption in adolescents. Methods Data were collected from a micro-longitudinal substudy of the age 15 wave of the Fragile Families and Child Wellbeing Study (n=589). Adolescents wore a wrist-actigraphy device and completed daily surveys for approximately one week (mean=5.6 days). Daily surveys assessed sleep quality and caffeinated beverage consumption (0=no caffeine, 1=any caffeine). Separate mixed models assessed whether actigraphy-measured sleep duration, timing, maintenance efficiency, and subjective quality predicted next-day caffeinated beverage consumption within and between adolescents. Variability of sleep duration and timing (SD), sleep regularity index, and social jetlag were tested as additional between-person predictors. Lagged models tested whether daily caffeinated beverage consumption predicted sleep that night (n=458; mean=5.2 days). Results Between-person results showed that adolescents who had more variable actigraphic sleep duration (OR=1.21, p=.042) and sleep midpoint (OR=1.27, p=.045) had greater odds of consuming caffeinated beverages compared to others. Within-person results showed that on days when adolescents consumed ≥1 caffeinated beverage, they had later sleep onset by (b±SEM) 17±6 mins (p=.003) that night and later wake time by 19±7 mins (p= .011) the next morning, compared to days when they did not consume caffeine. Sleep duration, timing, maintenance efficiency, and subjective quality did not predict next-day caffeinated beverage consumption (all p>.10). Conclusion Greater variability in sleep duration and timing and later sleep timing are risk factors for poor emotional and cardiometabolic health. Curbing caffeinated beverage consumption may aid in the maintenance of regular sleep schedules and advance sleep timing in adolescents, potentially improving physical and psychological health. Support (If Any) R01HD073352

0188 Associations between Preschoolers’ Behavioral Difficulties and Variability in Sleep Duration and Bedtime

Abstract Introduction Variability in children’s sleep patterns has been linked with health outcomes including obesity, poor mood, and behavioral difficulties. However, much of this evidence stems from parent-reported measures of sleep. Understanding these associations in preschool-age children using device-based measures is important as sleep habits tend to develop and stabilize during this time. The purpose of this study was to examine associations between parent-reported behavioral difficulties and device-measured sleep among preschoolers. Methods Ninety-five preschool-aged children (3-5 years, 51% female, 30% Black) with at least two valid nights of sleep were in included in this analysis. Children were asked to wear an Axivity AX3 accelerometer on their non-dominant wrist for 30 days. Parents completed the Strengths and Difficulties Questionnaire which assessed child behaviors over the past 6 months. Raw accelerometry data were processed with GGIR (v2.3). We used MixWild to conduct mixed effects location scale models with a random intercept and scale predicting nocturnal duration variability and bedtime variability. Time invariant behavior subscales (conduct problems, hyperactivity/inattention, peer relationship problems, emotional symptoms, prosocial behavior, and total difficulties) were included as predictors of child sleep duration and bedtime variability. Results Children had an average of 13.4 ± 7.4 (range 2-29) nights of valid data. Average nocturnal sleep duration was 9.7 ± 1.4 hours and average bedtime was 9:48 PM. There were no statistically significant associations between any SDQ subscales and variability in children’s sleep duration and bedtime. There was an association between random location and scale such that participants with later average bedtimes also had more variability in their bedtime (p < 0.001). Conclusion Variability in nocturnal sleep was not associated with parent reported behavioral difficulties, which is contrary to recent findings. It is unclear if sleep duration and bedtime variability are associated with day-level changes in children’s behavior. Additional work that emphasizes aspects of sleep beyond sleep duration is needed to advance our understanding of preschool-age children’s sleep. Support (If Any) This was supported by the National Institute of General Medical Sciences of the NIH for the UofSC Research Center for Child Well-Being (P20GM130420) and by the National Heart, Lung, and Blood Institute (F32HL154530).

0180 Sex Differences in the Association between Mood and Actigraphic Sleep Variability in Adolescents

Abstract Introduction Poor mental health in adolescents has been linked to more variable sleep. However, most studies use self-reported measures of sleep. There is also a lack of research on sex differences in these associations, which is important given that poor emotional health is more common in female than male adolescents. The current study examined whether sleep variability measured through actigraphy was associated differently with self-reported mood in female versus male adolescents in between-person analyses. Methods Data were collected from a micro-longitudinal substudy of the age 15 wave of the Fragile Families and Child Wellbeing Study. Adolescents wore a wrist-actigraphy device and completed daily surveys for approximately one week (mean=5.6 actigraphy days; n range: 577-604 depending on the mood variable) where they reported levels of loneliness, happiness, excitement, and anger on a five-point Likert scale (0, not at all, to 4, extremely). Separate mixed models assessed whether sex moderated the association between mean mood and actigraphy-measured sleep variability measures including residual standard deviation (riSD) of sleep duration, onset, and offset; sleep regularity index (SRI), and social jetlag (|midpoint of sleep on school nights – midpoint of sleep on free nights|; n for social jetlag ranged from 363-376 depending on the mood variable). Results In both sexes, greater average happiness (β=−.11, p=.009) and excitement (β=−.11, p=006) were associated with less variability in sleep duration, and greater average excitement was associated with higher SRI (β=.13, p=.001). Male adolescents reporting greater average happiness and excitement had less variability (riSD) in sleep onset (happiness β=−.15, p=.008; excitement β=−.14, p=.016) and lower levels of social jetlag (happiness β=−.25, p<.001; excitement β=−.22, p=.005), but these associations were null in female adolescents (all p>.20). Neither loneliness nor anger were associated with sleep variability measures in either sex (all p>.15). Conclusion Greater positive moods are associated with lower sleep variability, which may protect mental and physical health. Boosting positive mood in adolescents may assist in normalizing sleep schedules, and decreasing sleep variability may aid in the maintenance of positive emotional health, particularly for males. Future research may use a within-participant design to examine the direction of these associations. Support (If Any) R01HD073352

0105 Sleep timing and consistency are associated with the standardised test performance of Icelandic adolescents

Abstract Introduction Sleep has been shown to affect cognitive function in laboratory studies; however, its association to the academic performance of adolescents has largely been demonstrated using self-reported measures. Studies with objective measures of both sleep and academic performance are limited. The aim of the present study was to determine whether the free-living sleep quantity, quality, and timing of 15-year-old adolescents measured with wrist actiography are associated with their scores on national standardised examinations as an objective measure of academic achievement. Methods We measured sleep with wrist actiography for 1 week in 253 (150 girls) Icelandic adolescents with a mean (SD) age of 15.9 (0.3) years. Multiple linear regression was used to assess associations between sleep parameters and combined standardised examination scores in mathematics, English, and Icelandic obtained from the Icelandic Directorate of Education. Results We found that students went to bed at 00:49 hours (± 51.8 min) and slept for a mean (SD) of 6.6 (0.7) hr/night, with a median (interquartile range) night-to-night variation in sleep duration of 1.2 (0.7) hr and an efficiency of 88.1 (5.3)%. Combined analyses adjusted for sex, demonstrated that both bedtime and night-tonight variability in total sleep time were negatively associated with the average score across all topics. Sex-specific associations did not indicate clear differences between boys and girls. Conclusion These findings suggest that, in addition to appropriate sleep duration, public health guidance should also highlight the importance of early and consistent sleep schedules to academic achievement for both boys and girls. Support (If Any) National Institute of Diabetes and Digestive and Kidney Diseases intramural research program, Grant/Award Number: Z01 DK071013 and Z01 DK071014; Icelandic Centre for Research, Grant/ Award Number: 152509-051

Associations of chronotype and sleep patterns with metabolic syndrome in the Hispanic community health study/study of Latinos

ABSTRACT Sleep duration, sleep efficiency, and sleep timing have been shown to have potential effects on metabolic functions relevant to circadian rhythms. It is not clear if the impact of sleep patterns on metabolic risk factors is through sociocultural and environmental factors or circadian misalignment. We investigated the associations of sleep patterns, chronotype, and social jet lag with metabolic syndrome among non-shift worker Hispanic/Latino adults. We used cross-sectional data from the Sueño Ancillary Study of The Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Data from a subsample of 2189 participants aged 18–64 years were used in the analysis. Mean nightly sleep duration, mean sleep onset time, mean sleep offset time, mean sleep midpoint time, sleep efficiency, sleep variability (standard deviation (SD) of sleep duration, and SD of sleep midpoint), and time spent above light exposure threshold (1000 lux) in a day were assessed by wrist actigraphy (Acti-watch Spectrum). Chronotype was determined by the reduced Morningness-Eveningness Questionnaire. Medical conditions including dyslipidemia, hypertension, and diabetes mellitus were determined from a fasting blood specimen and physical exam at the baseline visit. To determine whether sleep patterns, light levels, chronotype, and social jetlag are associated with metabolic syndrome, multivariable logistic regression models were fitted, including variables with P < .15 in the univariate analysis. The results of the multivariable analysis demonstrated that in participants older than 40 years, intermediate chronotype (vs early) was significantly associated with a higher risk of metabolic syndrome (Odds ratio (95%CI): 1.33 (1.04,1.7)), while later chronotype (vs. early) in participants younger than 40 years was significantly associated with a lower risk of metabolic syndrome (Odds ratio (95%CI): 0.37 (0.14, 0.96)). Also, higher sleep efficiency was significantly associated with decreased odds of metabolic syndrome (Odds ratio (95%CI): 0.98 (0.96, 0.99)). Nightly sleep duration was not significantly different between two groups of participants with and without metabolic syndrome in multivariable analyses. There was no significant association between social jet lag and metabolic syndrome in multivariable analysis (p = .286). Moreover, there was no significant association between chronotype and social jet lag in multivariable analysis. The association between metabolic syndrome and chronotype is age-dependent. While early chronotype is associated with metabolic syndrome in younger individuals, it tended to be associated with lower odds for metabolic syndrome in older individuals.

Re-examining extreme sleep duration in bats: implications for sleep phylogeny, ecology, and function.

Bats, quoted as sleeping for up to 20 h a day, are an often used example of extreme sleep duration amongst mammals. Given that duration has historically been one of the primary metrics featured in comparative studies of sleep, it is important that species specific sleep durations are well founded. Here, we re-examined the evidence for the characterization of bats as extreme sleepers and discuss whether it provides a useful representation of the sleep behavior of Chiroptera. Although there are a wealth of activity data to suggest that the diurnal cycle of bats is dominated by rest, estimates of sleep time generated from electrophysiological analyses suggest considerable interspecific variation, ranging from 83% to a more moderate 61% of the 24 h day spent asleep. Temperature-dependent changes in the duration and electroencephalographic profile of sleep suggest that bats represent a unique model for investigating the relationship between sleep and torpor. Further sources of intra-specific variation in sleep duration, including the impact of artificial laboratory environments and sleep intensity, remain unexplored. Future studies conducted in naturalistic environments, using larger sample sizes and relying on a pre-determined set of defining criteria will undoubtedly provide novel insights into sleep in bats and other species.

Relationship of night sleep duration with health lifestyle, depressive symptoms, internet addiction in Chinese High school Students.

This study aimed to explore effects of night sleep duration and its relationships with health lifestyle, depressive symptoms and Internet addiction among high school students. In this study, we used multistage stratified random cluster sampling method. A total of 2149 adolescents aged 14-18years oldwere recruited in the study. Associations among sleep duration and demographic characteristics, health lifestyle, depressive symptoms and Internet addiction among Chinese students were analyzed by univariate analysis and binary logistic regression analysis. Then, the structural equation model (SEM) was used to study the relationships between sleep duration and other variables. The mean sleep duration was (6.56 ± 1.15) hours. Approximately 16.0% of all participants had short sleep duration, and 20.5% had long sleep duration.Binary logistic regression analysis revealed that having more high sugar drinks and fried foods were positively associated with short sleep duration. Depressive symptoms not only directly had a negatively impact on sleep duration, but also had an indirect effect on sleep duration through Internet addiction. Sleep problems are common within the population of adolescents. Depressive symptoms was an important factor in the prevention of abnormal sleep duration, and interventions that target Internet addiction is key to reduce inadequate sleep.

The onset of pubertal development and actigraphy-assessed sleep during middle childhood: Racial, gender, and genetic effects

ObjectiveThis study (1) examined pubertal development in relation to actigraphy-assessed sleep in twin children, and tested whether associations differed by child race and gender, (2) modeled genetic and environmental influences on pubertal development and sleep indicators, and (3) examined genetic and environmental influences on the covariation of puberty and sleep. DesignThe classic twin design was used to examine genetic and environmental contributions to puberty and sleep and their associations. SettingData were collected from community-dwelling urban and rural families of twins in the southwestern U.S. ParticipantsThe racially and socioeconomically diverse sample included 596 twin children (Mage = 8.41, SD = 0.69; 51.7% female; 66.3% white; 33.7% Hispanic; 170 monozygotic, 236 same-sex dizygotic, 188 opposite-sex dizygotic). MeasurementsPubertal development was assessed via parent report. Children wore actigraph watches for 7 nights (M = 6.81, SD = 0.67) to capture sleep duration, efficiency, midpoint, onset latency, and duration variability. ResultsIn contrast to extant literature with older youth, more advanced pubertal development was associated with longer sleep durations in Hispanic and white girls and higher sleep efficiency in white girls, though Hispanic girls demonstrated later sleep midpoints. Pubertal development was moderately heritable and there was a genetic influence on the covariance between puberty and sleep indicators. ConclusionsThis was the first study to examine the genetic and environmental influences on the covariation between puberty and sleep, and found genetic underpinnings between pubertal development and actigraphy-assessed sleep duration and efficiency, though sleep and puberty were almost entirely independent in twins at this age.

Neighborhood Disadvantage Is Associated with Lower Quality Sleep and More Variability in Sleep Duration among Urban Adolescents.

Differential social and contextual environments may contribute to adolescent sleep disparities, yet most prior studies are limited to self-reported sleep data and have not been conducted at a national level, limiting the variation in neighborhood contexts. This study examined the association between neighborhood disadvantage and objective measures of adolescent sleep. A racially and geographically diverse sample of American adolescents (N = 682) wore wrist-worn accelerometers, "actigraphs," for ≥ 5 nights. Neighborhood disadvantage was calculated using a standardized index of neighborhood characteristics (proportion of female-headed households, public assistance recipients, households in poverty, adults without high school degrees, and unemployed). Adolescents in more disadvantaged neighborhoods spent more time awake after falling asleep (4.0min/night, p < .05), a greater percentage of nighttime sleep intervals awake (1%, p < .01), and had less consistent sleep duration (11.6% higher standard deviation, p < .05). Sleep duration and timing did not differ across neighborhood groups. These findings demonstrate that adolescents who live in more disadvantaged neighborhoods have lower quality, less consistent sleep.

Minimum number of nights for reliable estimation of habitual sleep using a consumer sleep tracker

To determine the minimum number of nights required to reliably estimate weekly and monthly mean sleep duration and sleep variability measures from a consumer sleep technology (CST) device (Fitbit). Data comprised 107 144 nights from 1041 working adults aged 21-40 years. Intraclass correlation (ICC) analyses were conducted on both weekly and monthly time windows to determine the number of nights required to achieve ICC values of 0.60 and 0.80, corresponding to "good" and "very good" reliability thresholds. These minimum numbers were then validated on data collected 1-month and 1-year later. Minimally, 3 and 5 nights were required to obtain "good" and "very good" mean weekly total sleep time (TST) estimates, while 5 and 10 nights were required for monthly TST estimates. For weekday-only estimates, 2 and 3 nights were sufficient for weekly time windows while 3 and 7 nights sufficed for monthly time windows. Weekend-only estimates of monthly TST required 3 and 5 nights. TST variability required 5 and 6 nights for weekly time windows, and 11 and 18 nights for monthly time windows. Weekday-only weekly variability required 4 nights for both "good" and "very good" estimates while monthly variability required 9 and 14 nights. Weekend-only estimates of monthly variability required 5 and 7 nights. Error estimates made using data collected 1-month and 1-year later with these parameters were comparable to those associated with the original dataset. Studies should consider the metric, measurement window of interest, and desired reliability threshold to decide on the minimum number of nights required to assess habitual sleep using CST devices.

Socioeconomic status and infant nighttime sleep across the second year of life: The moderating role of infant attachment security.

This study examined socioeconomic status (SES) and attachment security as predictors of infant nighttime sleep during the second year. Participants included 128mothers (86% White) with infants (48.4% boys). Data collection took place between April, 2009 and February, 2014. At 12, 18, and 24months, infant sleep was assessed via actigraphy and daily diaries, and attachment with the Attachment Q-Set. SES indicators included income-to-needs ratios and education. Lower SES predicted greater variability in sleep duration and later sleep timing only for less secure infants. Less secure attachment was associated with poorer sleep at both between- and within-person levels, especially when infants were 12months of age. Results emphasize the complex interactive effects of environmental and relational factors on infant sleep.

Too Jittery to Sleep? Temporal Associations of Actigraphic Sleep and Caffeine in Adolescents.

Caffeine consumption has been linked to poor sleep health in adolescents, but it is unknown whether poor sleep predicts caffeine consumption, and/or whether caffeine consumption predicts poor sleep, particularly when sleep is measured objectively. Data were collected from a micro-longitudinal sub-study of the age 15 wave of the Fragile Families and Child Wellbeing Study (n = 589). Adolescents wore an actigraphy device and completed daily surveys for ~1 week. Daily surveys assessed subjective sleep quality and caffeinated beverage consumption (0 = no caffeine, 1 = any caffeine). Separate mixed models assessed whether actigraphy-measured sleep duration, timing, maintenance efficiency, and subjective quality predicted next-day caffeinated beverage consumption within and between adolescents. Variability (standard deviation) of sleep duration and timing, sleep regularity index, and social jetlag were tested as additional between-person predictors. Lagged models tested whether daily caffeinated beverage consumption predicted sleep that night (n = 458). Adolescents with more variable sleep duration and midpoint had higher average odds of consuming caffeinated beverages compared to others. After adolescents consumed ≥1 caffeinated beverage, they had later sleep onset that night and wake time the next morning than usual versus when they did not consume caffeine. Curbing caffeinated beverage consumption may aid in the maintenance of regular sleep schedules and advance sleep timing in adolescents.

Association Between the Anti-Aging Protein Klotho and Sleep Duration in General Population.

PurposeSleep duration is associated with aging. However, the relationship between sleep duration and the concentration of the protein klotho in the serum remains unknown in the general population of the United States. Hence, this study aimed at exploring the association between them.MethodsParticipants whose data included klotho protein and sleep duration variables in the National Health and Nutrition Examination Survey data from 2007 to 2016 were utilized for this analysis.ResultsSleep duration was non-linearly associated with the level of klotho protein in the serum, with a negative association between sleep duration and serum klotho concentration after adjusting for confounding variables (β = −7.6; 95% CI: −11.3, −4.0; P < 0.001). The conversion of the sleep duration from a continuous variable to a categorical variable (tertile: T1: <5.5 hours; T2: 5.5–7.5 hours; T3: >7.5 hours) revealed that the serum klotho of the participants in the highest tertile (>7.5 hours) was 21.9 pg/mL lower (95% CI: −38.6, −5.2; P = 0.01) than those in the lowest tertile (<5.5 hours).ConclusionOur results revealed that people who sleep more than 7.5 hours per night have decreased levels of the anti-aging protein klotho in their serum, thus being more at risk of aging-related syndromes.

Adolescents' sleep and adjustment: Reciprocal effects.

Reciprocal relations between sleep and adjustment were investigated. Participants included 246 adolescents (M=15.80years; 67.5% White, 32.5% Black/African American; 53% female, 47% male) at Time 1 (data collected 2012-2013), 227 at Time 2 (M=16.78years) and 215 at Time 3 (M=17.70years). Sleep-wake variables were measured with self-reports (sleepiness) and actigraphy (average sleep minutes and efficiency, variability in sleep minutes and efficiency). Adolescents reported on depression and anxiety symptoms, and parents reported on externalizing problems. Greater variability in sleep duration and efficiency as well as sleepiness predicted adjustment problems (range of R2 : 36%-60%). Reciprocal relations were supported mostly for sleepiness (range of R2 : 16%-32%). Results help understand bidirectional relations between sleep and adjustment.

Longitudinal associations between facets of sleep and adiposity in youth.

Beyond sleep duration, other facets of sleep such as variability and timing may be associated with obesity risk in youth. However, data are limited. Using a longitudinal design, this study tested whether multiple facets of sleep were associated with fat mass gain over 1 year. A convenience sample of non-treatment-seeking youth (age 8-17 years) wore actigraphy monitors for 14 days. Average weekly sleep duration, within-person sleep duration variability, weekend catch-up sleep, bedtime and wake time shift, social jet lag, bedtime, wake time, and sleep midpoint were calculated. The association of each facet of baseline sleep with 1-year fat mass, adjusting for baseline fat mass and height, was examined. A total of 137 youths (54.0% female; mean [SD], age 12.5 [2.6] years; 28.4% non-Hispanic Black or African American; baseline fat mass = 15.3 [8.9] kg; 1-year fat mass = 17.0 [10.0] kg; 28.5% with baseline overweight or obesity) were studied. Wake time (p = 0.03) and sleep midpoint (p = 0.02) were inversely associated with 1-year fat mass, such that earlier wake time and midpoint were associated with higher 1-year fat mass. No other facet of sleep was significantly associated with 1-year fat mass (p > 0.09). Using objective measures, youth with earlier wake times and sleep midpoints had greater gains in fat mass. Additional research is needed to determine whether sleep timing may be a modifiable target to prevent pediatric obesity.

Association of accelerometer-derived sleep measures with lifetime psychiatric diagnoses: A cross-sectional study of 89,205 participants from the UK Biobank.

BackgroundSleep problems are both symptoms of and modifiable risk factors for many psychiatric disorders. Wrist-worn accelerometers enable objective measurement of sleep at scale. Here, we aimed to examine the association of accelerometer-derived sleep measures with psychiatric diagnoses and polygenic risk scores in a large community-based cohort.Methods and findingsIn this post hoc cross-sectional analysis of the UK Biobank cohort, 10 interpretable sleep measures—bedtime, wake-up time, sleep duration, wake after sleep onset, sleep efficiency, number of awakenings, duration of longest sleep bout, number of naps, and variability in bedtime and sleep duration—were derived from 7-day accelerometry recordings across 89,205 participants (aged 43 to 79, 56% female, 97% self-reported white) taken between 2013 and 2015. These measures were examined for association with lifetime inpatient diagnoses of major depressive disorder, anxiety disorders, bipolar disorder/mania, and schizophrenia spectrum disorders from any time before the date of accelerometry, as well as polygenic risk scores for major depression, bipolar disorder, and schizophrenia. Covariates consisted of age and season at the time of the accelerometry recording, sex, Townsend deprivation index (an indicator of socioeconomic status), and the top 10 genotype principal components. We found that sleep pattern differences were ubiquitous across diagnoses: each diagnosis was associated with a median of 8.5 of the 10 accelerometer-derived sleep measures, with measures of sleep quality (for instance, sleep efficiency) generally more affected than mere sleep duration. Effect sizes were generally small: for instance, the largest magnitude effect size across the 4 diagnoses was β = −0.11 (95% confidence interval −0.13 to −0.10, p = 3 × 10−56, FDR = 6 × 10−55) for the association between lifetime inpatient major depressive disorder diagnosis and sleep efficiency. Associations largely replicated across ancestries and sexes, and accelerometry-derived measures were concordant with self-reported sleep properties. Limitations include the use of accelerometer-based sleep measurement and the time lag between psychiatric diagnoses and accelerometry.ConclusionsIn this study, we observed that sleep pattern differences are a transdiagnostic feature of individuals with lifetime mental illness, suggesting that they should be considered regardless of diagnosis. Accelerometry provides a scalable way to objectively measure sleep properties in psychiatric clinical research and practice, even across tens of thousands of individuals.

Day-to-day variation in sleep duration is associated with increased all-cause mortality.

There is a paucity of data on the association between day-to-day variation in sleep pattern and all-cause mortality. We aimed to investigate whether day-to-day variation in sleep duration and onset of sleep are associated with cardiovascular and all-cause mortality. We used data belonging to 388 unique patients from the Midlife in the United States 2 Biomarker study (2004-2009). Information on sleep onset, duration, and sleep-wake cycles was collected for 7 consecutive days using the Actiwatch device. Sleep irregularity was assessed using mean and standard deviations in sleep duration and time of onset of sleep over 7 days. Cox proportional regression analysis and the Fine and Gray subdistribution method were used with all-cause and cardiovascular mortality, respectively. Over a median of 8.6 years of follow-up, 37 patients died, including 10 deaths resulting from cardiovascular causes. There was no statistically significant increase in cardiovascular mortality with variation in sleep duration in the highest vs the lowest tertile (hazard ratio, 4.00; 0.45-35.48; P = .21). However, increased all-cause mortality was seen in the highest vs the lowest tertile (hazard ratio, 3.99; 1.33-11.94; P = .01). Multivariable model adjusting for confounders had higher all-cause mortality with increased sleep duration variation in the highest vs the lowest tertile: hazard ratio, 4.85; 1.52-15.49; P < .01). Day-to-day variation in sleep duration is associated with increased all-cause mortality but not cardiovascular mortality after adjusting for mean sleep duration, inflammation, diabetes, age, body mass index, renal function, and blood pressure. Irregularity in the onset of sleep is not associated with all-cause mortality or cardiovascular mortality. Katamreddy A, Uppal D, Ramani G, etal. Day-to-day variation in sleep duration is associated with increased all-cause mortality. J Clin Sleep Med. 2022;18(3):921-926.

Discrimination and adjustment in adolescence: the moderating role of sleep.

We examined multiple actigraphy-based sleep parameters as moderators of associations between experiences of general and racial discrimination and adolescent internalizing symptoms (anxiety, depression) and externalizing behavior (rule-breaking). Adolescent sex and race were examined as additional moderators. Participants were 272 adolescents (Mage = 17.3 years, SD = 0.76; 51% male; 59% White/European American, 41% Black/African American). Sleep was assessed using actigraphs for 7 consecutive nights from which sleep duration (minutes), efficiency, and variability in minutes over the week were derived. Youth reported on their experiences of general discrimination, racial discrimination, anxiety, depressive symptoms, and rule-breaking behavior. Both types of discrimination were associated with poorer adjustment outcomes. Longer sleep duration, greater sleep efficiency, and less variability in sleep duration were protective in associations between race-specific and general discrimination and internalizing symptoms. Findings for duration and efficiency were more pronounced for females such that the adverse effects of discrimination were minimized among females with longer and more efficient sleep. Greater variability in sleep exacerbated rule-breaking behavior among adolescents experiencing general or racial discrimination. Associations did not differ by adolescent race. Short and poor-quality sleep may exacerbate internalizing symptoms for adolescents experiencing discrimination, particularly females. Variability in sleep duration was a key moderator of associations between discrimination and internalizing symptoms as well as rule-breaking behavior. Findings illustrate that actigraphy-assessed sleep parameters play a key role in ameliorating or exacerbating adjustment problems associated with discrimination.

Seasonal variations in sleep duration and sleep complaints: A Swedish cohort study in middle-aged and older individuals.

Subjective sleep reports are widely used research tools in epidemiology. Whether sleep reports can differ between seasons is less clear. Using multivariable binary or multinomial logistic regression analyses, in the present Swedish cross-sectional two-centre cohort study (N=19,254; mean age 61years), we found that participants surveyed during the summer (June-August) were more likely to report short sleep duration (defined as ≤ 6hr) compared with those interviewed during the autumn (odds ratio [95% confidence interval]=1.14 [1.04-1.25]). Individuals interviewed in the winter (December-February) were less likely to report early awakenings compared with participants surveyed in the autumn (September-November; odds ratio [95% confidence interval]=0.85 [0.75-0.96]). Complaints of difficulties in falling asleep and disturbed sleep were less common among participants interviewed during spring (March-May) compared with those interviewed during the autumn (odds ratio [95% confidence interval]=0.86 [0.74-0.99] and 0.88 [0.79-0.98], respectively). No seasonal variations in reports of long sleep, difficulty maintaining sleep, or feeling not rested after sleep were observed. Additional subgroup analysis revealed that summer participants were more likely to report short sleep duration and early morning awakenings than individuals surveyed in winter. In conclusion, this Swedish study indicates that self-reported sleep characteristics may vary across seasons. Further studies are needed to confirm our findings.