bluuebunny/crossref_metadata_2025_split huggingface dataset:
0287 Humans are capable of achieving sufficient sleep in microgravity
Authors: Flynn-Evans Erin , Glaros Zachary , Jansen Rachel 
Published: May 2023

Abstract

Introduction
Studies consistently find that humans average approximately six hours of sleep per night in space, which is less than they sleep on Earth. It is unclear whether the sleep loss observed during spaceflight is related to modifiable factors, such as irregular scheduling and inadequate sleep environment or due to features of spaceflight that may alter physiology, such as microgravity. Recent missions have afforded crew better, more stable sleep schedules, and an improved sleep environment. Hence, the evaluation of sleep under these improved conditions should provide insight into the causes of sleep deficiency observed in space thus far.

Methods
Crewmembers (n = 19) wore actiwatches for two bouts of data collection lasting two weeks each before flight (at approximately L-270 and L-180), either continuously (n = 9) or for two weeks every two months while in space (n = 10), and for seven days postflight, immediately upon return to Earth. We compared sleep outcomes (sleep duration, wake after sleep onset [WASO], sleep efficiency, and sleep latency) between phases of flight using mixed effects models, with participant and intercept included as a random effect.

Results
Crewmembers averaged 7.3 +/- 0.4 hours of sleep per night in space. Though this was less than they achieved preflight (7.9 +/- 0.5) or postflight (7.8 +/- 0.8; F (2, 2866) = 86.26, p &lt; .0001, ηp2 = .06), this duration of sleep meets the recommended amount for optimal human health and well-being. Sleep efficiency (%) also increased inflight (88.7 +/- 2.7) compared to preflight (84.7 +/- 5.5) and postflight (84.4 +/- 6.1; F (2, 2630) = 124.08, p &lt; .0001, ηp2 = .09), while WASO (min) decreased inflight (29.6 +/- 8.2) compared to preflight (46.4 +/- 15.5) and postflight (48.7 +/- 16.0); F (2, 2629) = 285.90, p &lt; .0001, ηp2 = .18). There were no changes across these variables over time inflight.

Conclusion
We conclude that humans are capable of achieving sufficient sleep in space. Going forward, it is imperative that crewmembers are provided with stable schedules, with moderate workload, and environments that are conducive to sleep.

Support (if any)
NASA Human Factors and Behavioral Health Element, NASA Human Research Program
0294 Sleep Quality Ratings Predict Disagreement Between Daily Objective and Subjective Evaluations of Total Sleep Time in Firefighters
Authors: Marmis Ryan , McGoldrick-Ruth Logan , Kelly Monica , Haynes Patricia 
Published: May 2023

Abstract

Introduction
Accurate sleep assessment in firefighters is necessary to predict risk for error and also to identify sleep disorders like shift work disorder. Unfortunately, the primary tools for sleep assessment, actigraphy and sleep diaries, are sometimes discordant leaving interpretation of sleep unclear. This analysis sought to examine determinants of daily discrepancies between actigraphy and sleep diaries in firefighters to further understand the validity of these measures in an on-call, high risk occupation.

Methods
Daily sleep observations (n = 329) were collected from 60 firefighters over the course of a 6-day recovery period after working 5 non-consecutive 24-hour shifts (5/6 tour). Firefighter subjective sleep was measured using the consensus sleep diary, and objective sleep was measured via wrist-worn actigraphy (Actiwatch-2). Mixed linear modeling (MLM) was employed with purposeful selection of covariates to test which day-level variables (day of recovery, emotional state, sleep quality rating) and person-level variables (burnout, age, gender, minority status) best predicted disagreement in total sleep time (TST) between the sleep diary and actigraphy.

Results
The best-fitting model indicated that TST incongruency (subjective &gt; objective) occurred on days when individuals reported better sleep quality than their own average (Estimate = 19.87, SE = 5.02, p &lt; .001), more feelings of restfulness than their own average (Estimate = 22.70, SE = 4.77, p &lt; .001), less objective TST than their average (Estimate = -.37, SE = .04, p &lt; .001) and for persons with higher duration subjective TST (Estimate = 1.02, SE = .07) and lower duration objective TST (Estimate = -1.00, SE = .08, p &lt; .001). Neither burnout nor daily emotions predicted discrepancies in the two methods of assessment.

Conclusion
Employees most at-risk for potential overestimation of sleep duration were those that habitually received less objective TST or who habitually reported more TST. A discrepancy in measurement occurred on days when employees reported better-than-usual sleep quality and restfulness after sleep. These robust findings demonstrated that positive perception of sleep quality is a potential indicator of sleep overestimation in firefighters. Further research is necessary to examine the short- and long-term consequences of sleep overestimation in this occupation.

Support (if any)
#1R01HL117995-01A1
0295 Association between circadian rhythm of skin temperature and actigraphic sleep in free-living conditions: the HEIJO-KYO study
Authors: Tai Yoshiaki , Obayashi Kenji , Yamagami Yuki , Saeki Keigo 
Published: May 2023

Abstract

Introduction
Skin temperature manipulation with little or no change in core body temperature affects sleep-wake states. However, the significance of 24-hour variation in skin temperature to sleep quality is unclear. We aimed to evaluate whether the circadian rhythm of distal skin temperature (DST) affects sleep quality in free-living conditions and to provide additional evidence about the relationship between thermal input to the skin and sleep-wake states.

Methods
In this cross-sectional study of 2,177 community-dwelling adults (Mean age 68.8 [SD 8.0] years), we measured DST using a temperature logger (Thermochron iButton, Maxim) at 3-minute intervals for seven consecutive days to calculate non-parametric indicators of circadian rhythm: intradaily variability (IV), interdaily stability (IS), and relative amplitude (RA). The participants underwent simultaneous 7-day wrist actigraphy (GT3X-BT, ActiGraph) to measure sleep objectively. The association between non-parametric indicators and 7-day means of sleep measures was evaluated using multivariable linear regression models.

Results
Lower quartiles of IV and higher quartiles of IS and RA were significantly associated with higher sleep efficiency, shorter wake after sleep onset, and longer total sleep time (all p &lt;.001). After adjusting for potential confounders, including physical activity and outdoor temperature, the coefficients for the linear trend of sleep efficiency were −1.07 (95% confidence interval [CI]: −1.45, −0.69), 1.08 (95% CI: 0.75, 1.41), and 1.33 (95% CI: 0.83, 1.84) in IV, IS, and RA, respectively (all p &lt;.001).

Conclusion
Circadian rhythms of DST with higher fluctuation, lower regularity across days, and blunted amplitude were associated with worse sleep quality. Our findings may be applied in thermoregulatory interventions to enhance sleep quality.

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0296 Feasibility of a Sleep Health Intervention Mobile App for Long-Term Sleep Tracking and Usability in Cargo Pilots
Authors: Devine Jaime , Choynowski Jake , Hursh Steven 
Published: May 2023

Abstract

Introduction
Cargo operations frequently require pilots to cross multiple time zones and operate during the night, both of which are fatigue risks. Operators may benefit from an mobile app that provides individual warnings based on prior sleep history. The SleepTank™ mobile app provides warnings about fatigue risk based on the wearer’s individual sleep data as measured by Fitbit devices. In this pilot study, 10 cargo operators provided feedback about the accuracy and usability of the app and up to 100 days of continuous sleep data.

Methods
Ten (N=10) experienced cargo pilots from a major operator volunteered to wear a Fitbit Versa 2 or Charge 5 to evaluate the app over three months (June-October 2022). Pilots completed a Qualtrics online survey about their perceptions of the app’s accuracy and usability in October 2022. Data for up to 100 days was extracted at the end of the study period. Sleep data was summed by date to provide a 24-hour estimate of time in bed (TIB24), total sleep time (TST24), daily sleep intervals (DSI), and average sleep efficiency (SE). Changes to sleep behavior over time were explored using mixed model linear regression.

Results
Cargo pilots (N=10) wore the device with the app for an average of 69±29 days (Range: 25-100 days). Pilots’ TIB24 was 455±111 minutes, TST24 for 400±98 min, and SE was 88±4%. Pilots normally slept once per day (DSI: 1.2±0.5). Pilots’ sleep behavior did not change significantly over the study period (all p&gt; 0.4). All 10 rated the app as being useful, particularly for planning bedtimes and naps. 100% of the pilots rated SleepTank™ as accurate in predicting their fatigue levels.

Conclusion
Experienced cargo operators in this pilot study exhibited healthy sleep habits that were stable over the study period. Operators found the app useful and felt that app-provided fatigue ratings matched their perceived level of fatigue. App usage was not directly related to changes in objective sleep behavior but did validate operators’ experience of fatigue, which may lead to better identification of fatigue symptoms or proactive sleep planning to avoid periods of fatigue risk in the future.

Support (if any)
NA
0299 Sleep Hygiene in Nurses Using Data Collected from Consumer Sleep Technology (CST) with the SleepTank™ mobile app
Authors: Devine Jaime , Choynowski Jake , Hursh Steven , Farag Amany 
Published: May 2023

Abstract

Introduction
Nurses are prone to fatigue and sleep disturbances due to extended hour or shiftwork schedules. Fatigue in nurses not only compromises their own health and safety, but jeopardizes patient care as well. Nurses' work hours and overtime are currently not federally regulated. Fatigue risk mitigation strategies for nurses would benefit from understanding the relationship between sleep duration and work patterns in order to develop tools and regulations to protect against fatigue in the nursing profession.

Methods
Thirteen (N=13) nurses wore a Fitbit Versa 2 and used the SleepTank™ mobile app during a 6-week work rotation. Nurses in this study selected their own work shifts but did have duty-hour limitations. Sleep data was extracted via the mobile app; work schedules were self-reported. Sleep duration data was summed by date to provide a 24-hour estimate of time in bed (TIB24). Repeated measures analysis of variance (rmANOVA) explored differences in TIB24 by number of consecutive days worked and time. Pearson’s correlations evaluated the relationship between work and sleep.

Results
Nurses (N=13) wore the device with the app for an average of 54±15 days. Forty percent (40%) of the study period were work days (22±10). Nurses slept longer on non-work days (525±153 min) compared to work days (481±143; t=3.21, p=0.001). Nurses worked 2 days in a row on average (Range: 1-5). TIB24 was ~30 minutes shorter with each consecutive day worked (F5, 81=8.11, η2=0.08, p=&lt; 0.001). Routinely working a greater number of consecutive days was negatively correlated to TIB24 (r=0.71, p=0.009). Later average work start time was positively correlated with later bedtime (r=0.83, p&lt; 0.001) and shorter TIB24 (r=0.65, p=0.01).

Conclusion
Working more days consecutively and working later shifts was related to shorter sleep duration and later bedtime in nurses. However, given that nurses in this study routinely slept longer than 7 hours per night, poor sleep hygiene does not appear to be an issue in this population. The ability to select their own work shifts may allow nurses to select a schedule that permits healthy sleep behavior.

Support (if any)
N/A
0301 Associations between sleep and cognitive function in patients with Neurological post-acute sequelae of SARS-CoV-2 infection
Authors: Reid Kathryn , Ingram Louis , Jimenez Millenia , Orban Zachary , Zee Phyllis , Koralnik Igor , Maas Mathew 
Published: May 2023

Abstract

Introduction
Fatigue and sleep disturbance are among the most common neurological post-acute sequelae of SARS-CoV-2 infection (Neuro-PASC). We tested the hypothesis that impaired sleep and disrupted rest-activity rhythms are associated with impaired cognitive performance and greater burden of self-reported Neuro-PASC symptoms.

Methods
Forty adults (mean age 45 years, 69% female, 15% hospitalized post COVID) recruited from the Neuro-COVID-19 Clinic at Northwestern Memorial Hospital. Patients were evaluated via clinical assessment/history, chart review, patient reported outcomes for symptom severity (PROMIS cognitive function, fatigue, sleep disturbance, anxiety, depression), cognitive performance tests (NIH Toolbox modules for processing speed, attention, executive function, working memory), and 7 days of wrist actigraphy with a sleep log. We tested associations between objective and subjective measures using Pearson’s correlation and difference from population normative data using Student’s t test.

Results
39 participants provided sufficient data for analysis. The median number of discrete neurologic symptoms attributed to PASC was 6 with 87% reporting ≥4 neurologic symptoms. Fatigue, insomnia, and depression were common (~70% reporting each). Participants reported significant symptom burden in all PROMIS domains, and had measurably worse attention function along with borderline executive function, compared to population normative data (all p&lt; 0.001 except executive cognition p=0.056). Actigraphy showed Neuro-PASC patients had lower sleep efficiency and greater sleep latency (both p&lt; 0.001) but similar wakefulness after sleep onset (WASO) compared to age-matched population controls. Self-reported cognitive symptoms were correlated with severity of fatigue (p&lt; 0.001), anxiety (p=0.05), and depression (p&lt; 0.01), but not subjective sleep disturbance. There were no associations between actigraphy-measured sleep or rest-activity characteristics and self-reported symptoms. Patients with abnormal sleep characteristics (WASO, sleep efficiency, sleep latency) demonstrated impaired objective attention and executive function.

Conclusion
Neuro-PASC patients presenting to a post-COVID clinic have a significant burden of subjective mental health, sleep, fatigue and cognitive impairment symptoms, along with objectively abnormal cognitive performance and sleep, compared to population controls. Interventions to improve sleep could benefit cognitive performance. Prospective studies including larger populations of patients are needed to fully determine the interplay of sleep/circadian rhythm disruption on the cognitive function and quality of life in patients with PASC.

Support (if any)
Center for Circadian and Sleep Medicine
0304 Sleep Quality and Life Satisfaction in Severely Depressed Individuals
Authors: Zahorecz Brianna , Killgore William 
Published: May 2023

Abstract

Introduction
Better sleep quality correlates with higher life satisfaction. However, the strength of this relationship in the severely depressed population has yet to be explored. We hypothesized that better sleep quality would more strongly predict higher life satisfaction in severely depressed individuals, as compared to those who are not severely depressed.

Methods
We conducted a 13 month cross-sectional study on mental health during the main months of the COVID-19 lockdown (April 2020-April 2021). We included the Pittsburgh Sleep Quality Index (PSQI), the Beck Depression Inventory (BDI), and the Satisfaction With Life Scale (SWLS) in months 1 (N=1013), 4 (N=1043), 7 (N=1022), and 10 (N=1011). Using this data, we ran a linear regression between total SWLS scores, which increase with higher life satisfaction, and their responses to item six on the PSQI: “During the past month, how would you rate your sleep quality overall?” which ranged from “very bad” (score of 1) to “very good” (score of 4). The regression was split according to the set BDI score ranges for minimally (N=2178), mildly (N=624), moderately (N=667), and severely (N=609) depressed individuals from the entire sample.

Results
Total SWLS scores were positively correlated with PSQI sleep quality score in minimally, mildly, moderately, and severely depressed groups (Rminimally=0.187, p&lt; 0.001; Rmildly=0.129, p=0.001; Rmoderately=0.180, p&lt; 0.001; Rseverely=0.438, p&lt; 0.001). However, the R2 value was far larger in the severely depressed group than it was in all other groups R2adj/severely=0.191; versus R2adj/minimally=0.034, R2adj/mildly=0.015, and R2adj/moderately=0.031). This suggests that better sleep quality more strongly predicteds higher life satisfaction in severely depressed individuals, compared to those who were not severely depressed.

Conclusion
While poor sleep quality and lower life satisfaction both tend to be associated with more severe depression, these findings suggest the associations between sleep and life satisfaction are far stronger in those who are the most severely depressed. Consequently, these findings suggest that interventions that focus directly on improving sleep quality would likely be a fruitful approach to increase life satisfaction in severely depressed individuals.

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0305 Use of Sleep Medication Increases with Greater Severity of Hazardous Alcohol Use
Authors: Luevanos Maximus , Suckow Emmett , Hildebrand Lindsey , Franca Gabriela , Grandner Michael , Killgore William 
Published: May 2023

Abstract

Introduction
Hazardous alcohol use correlates with greater insomnia, potentially leading to increased use of sleep medications. However, combining sleep medications with alcohol can yield serious and even fatal health consequences. We examined the relationship between alcohol use and sleep medication use during the first year of the COVID-19 pandemic and hypothesized that greater alcohol use would correlate with increased use of sleep medication.

Methods
N=3,930 English-speaking adults from across the U.S. (Mage=37.2, SD=12.4) completed the Pittsburgh Sleep Quality Index (PSQI) and the Alcohol Use Disorders Identification Test (AUDIT) at one of four timepoints (April, July, and October of 2020 and in January of 2021). Individual use of sleep aids was measured by ranking them from 0 (none) to 2 (once or twice a week or more). Additionally, alcohol use was ranked from 0-3 where a higher score indicated higher alcohol dependence.

Results
Alcohol use was modestly but positively correlated with sleep medication use (r = 0.183, p&lt; 0.001). A chi-square analysis showed that the proportion of people reporting heavy use of sleep medications increased among those reporting greater severity of hazardous alcohol use (p&lt; 0.001). Specifically, 21.8% of those in the non-hazardous drinking category reported heavy use of sleep medications, while 25.3% of those in the hazardous drinking group described heavy sleep medication use. For those meeting criteria for probable alcohol dependence, 39.7% reported heavy sleep medication use, and 57.3% meeting criteria for severe alcohol dependence reported heavy sleep medication use.

Conclusion
We found that individuals who scored higher on alcohol use scored higher on sleep medication use, consistent with our hypothesis. These results show that during the COVID-19 pandemic, hazardous alcohol use and sleep medication use were significantly associated. Such findings are concerning, because when combined, alcohol and sleep medications can lead to serious health consequences, including impaired neurocognitive functioning, sleep disruption, parasomnias, risk of overdose, and even death. Given the potential severe risks associated with this behavior, increased clinical assessment, monitoring, and counseling about the dangers of mixing sleep medication with alcohol is warranted. Further work should identify the causal direction and potential mediating factors driving these associations.

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0309 Light exposure before bedtime in pregnancy is associated with a higher risk of gestational diabetes
Authors: Kim Minjee , Facco Francesca , Braun Rosemary , Wolf Michael , Garcia-Canga Blas , Grobman William , Zee Phyllis , Reid Kathryn 
Published: May 2023

Abstract

Introduction
Evidence suggests a link between mistimed light exposure and impaired glucose regulation among nonpregnant adults, yet little is known about the magnitude and significance of evening light exposure during pregnancy. This study examined the relationship between evening light exposure before sleep, during pregnancy, and the incidence of gestational diabetes mellitus (GDM).

Methods
In this prospective cohort study conducted at 8 U.S. clinical sites, nulliparous women wore a wrist actigraphy monitor and completed a daily sleep diary for seven days between 160 and 216 weeks’ gestation. The primary exposure variable was time spent above 10 lux (dim light) during the three hours preceding sleep onset (“TAT10 pre-sleep”), averaged over valid days of recording and categorized to tercile groups (“High”, “Medium”, “Low”). Primary outcome variable was the incidence of GDM. Associations of TAT10 pre-sleep groups with baseline characteristics, sleep and activity variables were examined with Chi-squared and Kruskal-Wallis rank sum tests. Univariate and multiple logistic regression models were used to characterize the relationship between pre-sleep light exposure and GDM.

Results
901 eligible women consented to participate; 758 submitted valid actigraphy recordings. Excluding women with pre-gestational diabetes and those with unknown gestational diabetes status, 741 were included in the analysis. Greater pre-sleep light exposure was associated with an increased risk of GDM (odds ratio [95% confidence interval]: 5.49 [1.8–23.84] in high and 4.05 [1.27–17.94] in medium vs 1 [reference] in low group). Women in the high group had more daytime light and were less likely to be late (midpoint &gt; 5AM) or fragmented (wake after sleep onset ≥ 75th percentile) sleepers. Sleep duration, mean activity level, and light during sleep were not different between groups. After adjusting separately for age, body mass index, race/ethnicity, sleep duration, sleep midpoint, education, employment schedule, season, and daytime light exposure, pre-sleep light exposure remained significantly associated with GDM.

Conclusion
Increased evening light exposure in pregnancy may be an under-recognized, potentially modifiable risk factor for GDM. Future research should investigate light-targeted interventions as a potential preventive strategy for GDM.

Support (if any)
R01HL105549, nuMoM2b Network