Midpoint Time Research Articles

Promotion of professional quality of life through reducing fears of compassion and compassion fatigue: Application of the Compassionate Mind Model to Specialist Community Public Health Nurses (Health Visiting) training.

To identify whether a Compassionate Mind Model-based curriculum reduces students' perceived fears of compassion and improves their professional well-being. Enabling compassion is mandatory within nurse education but evidencing it is challenging. Research suggests that application of the Compassionate Mind Model might reduce students' fears of compassion and also decrease compassion fatigue. This study reports outcomes of a post-registration curriculum based on that model for training Specialist Community Public Health Nurses (Health Visiting). A quantitative, prospective evaluation of a 12-month training course for Health Visiting students. Reporting was guided by the STROBE checklist for observational studies. Fears of compassion scales were applied at course start (time 1), mid-point (time 2; +6months) and end (time 3; +12months) to evaluate fears of compassion of 26 post-registration student Health Visitors (81% of course cohort) who provided data at all three points. The Professional Quality of Life tool was administered simultaneously to evaluate compassion satisfaction and burnout/secondary traumatic stress (compassion fatigue). Between time 1 and time 3, mean fears of compassion scores decreased by 16.6-48.5% (repeated measures analysis of variance); mid-point scores were intermediary. At time 3, compassion satisfaction had increased slightly (+4.1%), negatively correlated with fears of compassion for self (r=-0.602; p=.001; n=26) and fears of receiving compassion from others (r=-0.568; p=.002; n=26). Burnout score decreased by 18.7%, correlated positively with fear of compassion for self (r=0.493; p=.011; n=26) and fear of receiving compassion from others (r=0.615; p=.001; n=26). Secondary traumatic stress score decreased by 16.5% but was not correlated with any fear of compassion. Findings suggest that application of the Compassionate Mind Model might reduce practitioners' fears of compassion linked to a decrease in risk of compassion fatigue. The Compassionate Mind Model could provide an effective vehicle to promote compassion and nurse well-being.

Pupils with negative social jetlag in Japan are hypothesised to constitute a discrete population

Social jetlag (SJL) is the difference between the midpoint time of sleep between weekend and weekday. SJL is experienced by many adolescents and is a matter of concern in public health. In private experiences, pupils who were forced to wake up early on non-school day mornings to engage in hard physical activity and who had little time for sleep on non-school nights were identified. These pupils are supposed to show negative SJL values. However, few studies have described pupils with negative SJL values. The current study aimed to raise a hypothesis that pupils with negative SJL might constitute a discrete population with typical characteristic features. A total of 2,722 questionnaires obtained from pupils in grades 5 to 12 were assessed by the multiple comparison test of the Dunnett method to determine significant differences in the lifestyle habits among SJL categories (SJL-I, <0 h; SJL-II, 0–1 h; SJL-III, 1–2 h; SJL-IV, 2 h or more). Pupils with SJL-I were mostly male compared to those in SJL-II. Physical activity score showed a significantly higher value in SJL-I than SJL-II, while that in SJL-III and SJL-IV revealed significantly lower values than that in SJL-II. Contrarily, non-school day screen time and non-school night sleep duration showed significantly lower values in SJL-I than SJL-II, while those in SJL-III and SJL-IV revealed significantly higher values than those in SJL-II. After-school activity score showed a significantly higher value in SJL-I than SJL-II, while that in SJL-III and SJL-IV revealed lower values than that in SJL-II. At least in Japan, a hypothesis that pupils with negative SJL constitutes a discrete population with typical characteristic features (predominantly male, higher physical activity, and after-school activity scores; less non-school day screen time; and shorter non-school night sleep duration) was raised. Further studies are needed to confirm this hypothesis.

SLEEP DURATION AND TIMING ARE NOT ASSOCIATED WITH ANTIMULLERIAN HORMONE LEVELS

Many women who consider future family building seek advice regarding modifiable behaviors and reproductive health. To determine if sleep duration and timing are associated with AMH levels in a reproductive aged, Midwestern cohort of women. Cross sectional study. 200 women aged 18-44 years with regular menstrual cycles were enrolled into the LORE study, a cross-sectional cohort study designed to investigate associations between lifestyle factors and ovarian reserve. Women who were currently pregnant or who had history of major chronic illness, infertility or ovarian surgery were excluded. Fasting blood was drawn and stored at -80 degrees for batched analysis. Samples were run on the Roche Elecsys analyzer for AMH levels. Participants also completed a survey that included questions regarding typical bedtime and wake time on work and non-work days. Sleep measures included duration of sleep, midsleep point (defined as the midpoint time between bedtime and wake time, also known as chronotype), and social jetlag (the difference in midsleep point on workdays and non-work days of >1 hour). Standard bivariate statistics were run to determine associations between sleep duration, timing of sleep and AMH levels. SPSS v.25 was used for analysis. Participants had an average age of 30.9 ± 6.7 years and an average body mass index of 28.3 ±7.1. The majority of the participants were white (n=136, 68%); thirty percent were black (n=60). The average AMH level was 2.9 ±2.0 ng/mL. Average duration of sleep was 7.2 hours (Range 4.0 to 11.0 hours). Average mid sleep point on work nights was 2:51 AM and on non-work nights was 3:54 AM. Average social jet lag was 1:31 hours (range 0 to 14:30 hours). None of these measures were associated with AMH. This data suggests that for healthy, reproductive aged women in the Midwest, modifying sleep duration and timing is unlikely to improve or adversely affect AMH.

Children's objective sleep assessed with wrist-based accelerometers: strong heritability of objective quantity and quality unique from parent-reported sleep.

Children's poor sleep is a risk factor for lower cognitive functioning and internalizing and externalizing problems. It is unclear whether genetic and environmental influences vary based on sleep assessment and no studies to date have examined genetic and environmental contributions to links between multiple objective and subjective sleep indicators. Further, nearly all heritability studies rely on subjective parent- or self-report measures of sleep duration and problems. Given these gaps in the literature, we (1) modeled genetic and environmental influences on multiple objective and subjective sleep indicators and (2) estimated genetic and environmental covariances between objective and subjective sleep indicators in middle childhood. Participants were 608 twin children (MZ = 178, same-sex DZ = 234, opposite-sex DZ = 190) assessed at 8 years of age (SD = 0.63 years). Objective nighttime sleep duration, efficiency, sleep onset latency (SOL), midpoint time, and midpoint variability were collected from actigraph watches worn for 7 nights (Mnights = 6.83, SD = 0.62). Children's nighttime sleep duration and daytime sleepiness were assessed via parent report. Findings suggested high additive genetic influence on objective sleep quantity and quality, whereas objective SOL, sleep midpoint time, midpoint variability, parent-reported sleep duration, and daytime sleepiness were largely influenced by the shared environment. Common genetic factors explained associations between objective sleep quantity and quality, but genetics did not account for links with parent-reported sleep duration, midpoint time, or midpoint variability. Thus, objective and parent-reported assessments of children's sleep have unique genetic etiologies and should not be used interchangeably in the sleep literature.

P0796THE PREVALENCE AND INCIDENCE OF COGNITIVE IMPAIRMENT IN A COHORT OF CHRONIC KIDNEY DISEASE PATIENTS WITH CONCOMITANT DIABETES ATTENDING A SPECIALIST NEPHROLOGY CLINIC

Abstract Background and Aims Chronic kidney disease (CKD) is a global healthcare problem associated with several comorbid conditions including, cardiovascular disease, and diabetes, all of which are strong risk factors for the development of significant cognitive impairment. We recently reported the baseline outcomes of our older adult cohort with mild to moderate CKD (stages 3-4) and diabetes, where 48% were found to have a cognitive impairment ranging from mild to severe symptoms. [1] This study reports the outcomes at 36-months post baseline of the prevalence and incidence of cognitive impairment in this cohort the patients who at baseline were considered to have normal cognitive function. Method Cognitive function was assessed in patients over aged 55 years, with an estimated glomerular filtration rate &amp;lt; 45ml/min/1.73m 2, attending a renal and diabetes outpatient clinic, at baseline and at 36-months. The diagnosis of cognitive impairment was based upon patient and informant interview, case note review, neuropsychological assessment and application of Diagnostic and Statistical Manual of Mental disorders version 5 (DSM-5) and Petersen’s criteria for mild cognitive impairment (MCI). The incidence of cognitive impairment was calculated by dividing the number of new cases during study follow-up, by the person-time at risk throughout the observation period. Since it is not possible to precisely determine when a person actually develops cognitive impairment between baseline and follow-up, the midpoint of time between having normal cognition and becoming a case is assumed. Results Ninety-two patients without cognitive impairment at baseline, were included in this investigation (mean age of 75.8 + 9.1; 49 males: 43 female). Upon neuropsychological assessment and the application of DSM-5 criteria at follow-up, it was revealed that 25/92 (27%) of the cohort had developed a cognitive impairment ranging from MCI (n=19), to major symptoms (n = 6). The crude prevalence for MCI was 20.6%, and for dementia it was 6.5%. The total person years in the study were 237.38 years, with an overall incidence rate of 10.53 (95% Confidence interval 6.82-15.55) per 100 person-years. Conclusion This longitudinal cohort investigation reports the prevalence and incidence of new cases of cognitive impairment ranging from MCI to dementia in CKD. The crude prevalence in the current investigation for the development of cognitive impairment was 27%. The overall incidence rate for new cases of NCD was just over 10%. In other words, for every 100 patients in our current investigation we would estimate that around 10 will develop some a cognitive impairment ranging from MCI to dementia per year. Our findings from this and our previous investigation suggest that a significant number of CKD patients are at risk for the development of significant neurodegenerative conditions and in view of this cognitive function should be screened and monitored routinely in clinical practice. This will assist with appropriate health service planning, service development, clinical interventions and the assessment of the effectiveness of new and existing treatments services.

Sleep Duration and Timing in the Medium- to Long-Term Post-Bariatric Surgery.

Sleep duration improves short-term following bariatric surgery; however, little is known about its association with bodyweight medium- to long-term post-surgery. The purpose of this study was to describe sleep duration and its relationship with BMI and body composition. Forty-nine individuals, with a BMI of 36.6 ± 9.8kg/m2, regained 26.4 ± 17.8% of their lost weight 9.5 ± 3.3years post-surgery (range 3-16years). Sleep logs and ActivPAL3 accelerometers were used to assess sleep duration. Participants averaged 7.9 ± 1.6h/day and 8.5 ± 1.7h/day of sleep for weekdays and weekends, respectively (P < 0.01). A positive association between delta weekend-weekday sleep timing midpoint with BMI (β = 0.03, 95% CI = 0.01, 0.06; P = 0.01) was noted in the multivariable-adjusted model. On average, this sample achieved recommended sleep durations medium- to long-term post-surgery. Having an earlier sleep timing midpoint during the weekend may be associated with lower BMI.

Implementing a managed clinical network in a small country: A New Zealand case study

ABSTRACT The majority of research into Managed Clinical Networks (MCN) has been undertaken in large countries; little is known about the implementation of MCNs in small countries. Using a prospective, longitudinal, qualitative method, this three-year case study explored the development and implementation of a New Zealand palliative care MCN, particularly focusing on the establishment, mid-point, and completion time points. The analysis showed throughout the three years, the MCN failed to implement the guiding principles of MCNs. This may have been influenced by the small county context where clinicians and health provider organizations know each other well and compete for government-allocated resources and other funding (e.g. grants and donations). MCNs remain widely supported as a tool to achieve clinical representation in governance, particularly where change is needed to support equitable service delivery. However, it is possible in small country settings that MCNs require a different approach to leadership and development to achieve effective governance and implementation.

Sleep patterns and sleep deprivation recorded by actigraphy in 4th-grade and 5th-grade students

ObjectiveThis study investigates sleep patterns of fourth- and fifth-grade students using actigraphy. MethodsThe study included 257 students enrolled in a Southwestern US school district who participated in a novel sleep science curriculum during the Spring 2016–17 and Fall 2017-18 semesters and met the study inclusion criteria. As part of this curriculum, participants underwent 5–7 days of continuous wrist actigraphy and completed an online sleep diary. ResultsApproximately two-thirds of the 9-11-year-old fourth- and fifth-grade students slept less than the minimum 9 h per night recommended by both the American Academy of Sleep Medicine/Sleep Research Society and the National Sleep Foundation. The sleep midpoint time on weekends was about 1 h later than on weekdays. There was a significant effect of age on sleep duration. Compared to 9-year old students, a larger proportion of 10-year old students had a sleep duration less than 8.5 h. Boys had shorter sleep duration than girls, and a larger percentage of boys obtained less than 9 h of sleep compared to girls. ConclusionsInsufficient sleep is a highly prevalent condition among 9-11-year-old fourth- and fifth-grade elementary students. Importantly, there is a difference between sleep patterns on weekdays and weekends which may portend greater problems with sleep in adolescence and young adulthood.

Propofol versus midazolam in sedation for upper gastrointestinal endoscopy

Background: Upper gastrointestinal endoscopy [either diagnostic or therapeutic] is widely practiced under conscious sedation. However, the standard sedative agent or drug combination is not yet well established.Aim of the work: Comparison between propofol-fentanyl and midazolam-fentanyl for sedation in upper gastrointestinal endoscopy.Patients and methods: Sixty patients from those scheduled to undergo upper gastrointestinal endoscopy at the Gastrointestinal Endoscopy Unit were included. Patients were divided into two equal groups: propofol-fentanyl and midazolam fentanyl. The Anesthetist scheduled to perform the procedures was oriented by the drug, while patients did not know the sedating drug. Prior to the procedure, a clinical history and physical examination was carried out, and throughout the procedure the patient was monitored for blood pressure, heart rate, respiratory rate, and oxygen saturation. Both groups were compared regarding time to recovery, patient satisfaction, physician satisfaction and adverse events.Results: Recovery time was significantly shorter, patient and physician satisfaction scores were significantly higher among propofol group. On the other side, systolic blood pressure was significantly lower in propofol group at midpoint and recovery times, while oxygen saturation was significantly reduced in midazolam group at intermediate point of the procedure. Finally, hypoxia was significantly higher among midazolam group [reported in 20.0%], versus [none] in propofol group. No other adverse events were encountered.Conclusion: Propofol is better sedative than midazolam for upper gastrointestinal endoscopy. Thus, it should be used as a first-line drug in sedation in our endoscopy units.

The Effect of High Intensity Interval Training Versus Steady State Aerobic Training on Skin Microvascular Reactivity in Moderately Active Young Adults: A Pilot Study

A sedentary lifestyle is associated with endothelial dysfunction, leading to vascular pathology and impaired microvascular reactivity (MVR). Enhanced endothelial functioning has been seen in aerobically trained individuals. The purpose of this study was to determine if there was a differential training response of skin MVR in response to high intensity aerobic interval training (HIAIT) as compared to steady state aerobic training (SSAT). The study involved 16 moderately active male students (age: 20.93 &amp;plusmn; 5.05 yrs). They were randomly assigned to one of three groups; HIAIT, SSAT, and control group (CG). Baseline testing was performed to determine the VO2max, lactate threshold, blood pressure, body composition and a post-occlusive reactive hyperemia response (PORH) test was used to assess microvascular reactivity on the right palmer forearm using a moorVMS-Laser Doppler Flowmetry (LDF) These parameters were reassessed after three weeks (mid-point) and six-weeks (post intervention) weeks. Statistical significance was set at p&amp;le;0.05. There were no significant interactions between the variables measured in the three groups over time. There was a positive linear relationship in the SSAT group for PORHmax/time to peak (Tp) at baseline (r = 0.998, p = 0.039), midpoint (r = 0.992, p = 0.083), and the post intervention (r = 0.987, p = 0.103). Training in the SSAT group had improved PORHpeak at midpoint and post intervention time points (r = 0.999, p = 0.22; r = 1, p = 0.006; r = 1, p = 0.011). Training in either the HIAIT or the SSAT group had no significant effect on skin MVR in moderately active young adults. SSAT did display a positive linear relationship with PORHmax/Tp, and PORHpeak, which are variables influencing skin MVR.

Photon-weighted barycentric correction and its importance for precise radial velocities

ABSTRACT When applying the barycentric correction to a precise radial velocity measurement, it is common practice to calculate its value only at the photon-weighted mid-point time of the observation instead of integrating over the entire exposure. However, since the barycentric correction does not change linearly with time, this leads to systematic errors in the derived radial velocities. The typical magnitude of this second-order effect is of order 10 cm s−1, but it depends on several parameters, e.g. the latitude of the observatory, the position of the target on the sky, and the exposure time. We show that there are realistic observing scenarios, where the errors can amount to more than 1 m s−1. We therefore recommend that instruments operating in this regime always record and store the exposure meter flux curve (or a similar measure) to be used as photon-weights for the barycentric correction. In existing data, if the flux curve is no longer available, we argue that second-order errors in the barycentric correction can be mitigated by adding a correction term assuming constant flux.

A Second-Order Advection-Reflection Solver

Zehnder et al. [2018] recently introduced an advection-reflection method for fluid simulation that dramatically reduces artificial dissipation. We establish a connection between their method and the implicit midpoint time integration scheme, and present a simple modification to obtain an advection-reflection scheme with second-order accuracy in time. We compare with existing alternatives, including a second-order semi-Lagrangian method based on BDF2, and demonstrate the improved energy-preservation properties.

Behavioral Predictors of Weight Regain in Postmenopausal Women: Exploratory Results From the Breast Cancer and Exercise Trial in Alberta.

ObjectiveThis secondary analysis assessed associations between changes in energy balance and sleep behaviors and the risk of weight regain following exercise‐induced weight loss.MethodsOf 400 participants initially randomized in the Breast Cancer and Exercise Trial in Alberta (BETA), 227 lost weight following the moderate‐ to vigorous‐intensity exercise intervention (−4.2 ± 3.6 kg) and were included in this analysis. Self‐reported energy intake (EI), sleep duration, quality and timing, and objective measurements of physical activity (PA) and sedentary time were collected at the end of the intervention and the end of follow‐up. Linear regression models assessed associations between changes in these behaviors and risk of weight regain during follow‐up.ResultsParticipants regained 43% of the weight lost during follow‐up. Reductions in moderate to vigorous PA (β = −1.00; 95% CI = −1.74 to −0.25 h/d; P = 0.01) and steps per day (β = −0.0003; 95% CI = −0.0005 to −0.0001 steps/d; P = 0.004); increases in sedentary time (β = 0.54; 95% CI = 0.67 to 1.02 h/d; P = 0.03), EI (β = 0.001; 95% CI = 0.0003 to 0.002 kcal; P = 0.01), and fat intake (β = 0.004; 95% CI = 0.001 to 0.006 kcal; P = 0.002); and delayed sleep timing midpoint (β = 0.02; 95% CI = 0.004 to 0.03 min; P = 0.01) were associated with weight regain during follow‐up.ConclusionsThese exploratory results suggest that reductions in moderate to vigorous PA; increases in EI, fat intake, and sedentary time; and delayed sleep timing midpoint were significantly associated with risk of weight regain.

PER3 variable number tandem repeat (VNTR) polymorphism modulates the circadian variation of the descending pain modulatory system in healthy subjects

We evaluated the circadian pattern of variation of the descending pain modulatory system (DPMS) using a conditioned pain modulation (CPM) paradigm according to the variable-number tandem-repeat (VNTR) of the clock gene PER3 polymorphism. We assessed the relationship between the genotypes PER34/4 and PER35/5 and the temporal pattern of variation across the day using the following measures: the heat pain threshold (HPT), the cold pressure test (CPT), and the serum levels of BDNF and S100-B protein. The ∆-values (from afternoon to morning) of these measures were used for the analysis. The circadian phenotype was according to the mid-point sleep time established by the Munich ChronoType Questionnaire (MCTQ). We included 18 healthy volunteers (15 women) ages 18 to 30. A Generalized Linear Model (GLM) revealed a significant difference in the ∆-CPM-task between Per34/4 and Per35/5 genotypes, with means (SDs) of −0.41 (0.78) vs. 0.67 (0.90) (χ2 = 7.256; df = 1′ P = 0.007), respectively. Both sleep deprivation of at least 2 h/day (B = −0.96, 95% confidence interval (CI) = −1.86 to −0.11)) and the ∆-S100-B protein (−0.03, 95% CI = −0.06 to −0.02) were negatively correlated with the ∆-CPM-task, while the ∆-BDNF was positively correlated with the ∆-CPM-task (0.015, 95% CI = 0.01 to 0.03). We observed a difference in the ∆-CPT between PER34/4 and PER35/5 (0.11 (4.51) vs. 4.00 (2.60), respectively) (χ2 = 22.251; df = 1 P = 0.001). These findings suggest that the polymorphism of PER35/5 is associated with a decrease in the inhibitory function of the DPMS over the course of the day. However, sleep deprivation is an independent factor that also reduces the inhibitory function of the DPMS, regardless of the PER3 VNTR polymorphism.

Sleep and cancer incidence in Alberta's Tomorrow Project cohort.

Few studies have examined associations between sleep duration with combined and site-specific cancers within the same cohort. Additionally, no study to date has assessed associations between sleep timing midpoint and cancer incidence. Therefore, we aimed to investigate associations between self-reported sleep duration and sleep timing midpoint with combined and site-specific cancer incidence in Alberta's Tomorrow Project (ATP) cohort. The sleep duration analysis included 45,984 Albertans aged 35-69 years recruited from 2001-2015. Sleep timing midpoint (wake-time - ½ sleep duration) was assessed in a subset of ATP participants (n = 19,822). Incident cancer cases were determined through linkage with the Alberta Cancer Registry in June 2017. Cox proportional hazard regression models evaluated the effects of sleep duration and sleep timing midpoint on combined and seven site-specific cancers. A total of 2,428 and 1,322 incident cancer cases were observed in the sleep duration and sleep timing analyses, respectively. Reporting >9 h of sleep/night versus 7-9 h of sleep/night was associated with an increased incidence of non-Hodgkin lymphoma (hazard ratio [HR] = 2.14, 95% confidence interval [CI]: 1.14-4.01; p = 0.02) and hematological (HR = 1.70, 95% CI: 1.03-2.82; p = 0.04) cancers. A later sleep timing midpoint (>4 h 8 min) versus an intermediate sleep timing midpoint (3 h 47 min-4 h 8 min) was associated with an increased incidence of combined (HR = 1.20, 95% CI: 1.04-1.37; p = 0.01) and breast (HR = 1.49, 95% CI: 1.09-2.03; p = 0.01) cancers. Sleep duration and sleep timing may play a role in cancer etiology. Studies including objective sleep assessments are needed to corroborate these findings.

A fully implicit, conservative, non-linear, electromagnetic hybrid particle-ion/fluid-electron algorithm

The quasi-neutral hybrid model with kinetic ions and fluid electrons is a promising approach for bridging the inherent multi-scale nature of many problems in space and laboratory plasmas. Here, a novel, implicit, particle-in-cell based scheme for the hybrid model is derived for fully 3D electromagnetic problems with multiple ion species, which features global mass, momentum and energy conservation. The scheme includes sub-cycling and orbit-averaging for the ions, with cell-centered finite differences and implicit midpoint time advance. To reduce discrete particle noise, the scheme allows arbitrary-order shape functions for the particle-mesh interpolations and the application of conservative binomial smoothing. The algorithm is verified for a number of test problems to demonstrate the correctness of the implementation, the unique conservation properties, and the favorable stability properties of the new scheme. In particular, there is no indication of unstable growth of the finite-grid instability for a population of cold ions drifting through a uniform spatial mesh, in a set-up where several commonly used non-conservative schemes are highly unstable.

A quantitative method to compare the effect of thermal aging on the mechanical performance of fire protective fabrics

ABSTRACTA method has been proposed to provide a means to compare in a quantitative and comprehensive way the mechanical performance of fire protective fabrics under long‐term thermal exposure. These high‐performance materials experience a reduction in their performance overtime due to the various conditions they are exposed to during the lifetime of the clothing. The proposed method consists in a system of two equations fitting the time–temperature‐performance data: the Arrhenius model combined with the time–temperature superposition principle, and the three‐parameter Hill equation. The result of the data analysis using this method is provided in terms of four parameters: the temperature effect, the time rate, the degradation midpoint time, and the ultimate strength. It was used to compare the effect of accelerated thermal aging on the tear strength of seven different fabrics used in fire protective clothing. In all cases, a very good agreement was observed with both the Arrhenius model and the Hill equation. However, none of the fabrics studied appeared to stand as displaying all the characteristics that would be ideal for long‐term fire protection. The best solution is thus a compromise that will depend on the type of activity conducted and the type of conditions experienced. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47045.

Sleep and Cancer Incidence in Alberta's Tomorrow Project Cohort

Abstract We aimed to investigate the association between self-reported sleep duration and sleep timing midpoint with all- and site-specific cancer incidence in Alberta's Tomorrow Project (ATP) cohort. Methods: The analysis for sleep duration included 46,300 Albertans aged 35–65 years at baseline from the ATP cohort recruited from 2001–2015. Sleep timing midpoint (wake-time – ½ sleep duration) was assessed in a subset of ATP participants (n = 19,820). Cancer incidence was determined through record linkage with the Alberta Cancer Registry in December 2016. Cox proportional hazard regression models evaluated the effects of sleep duration and sleep timing midpoint categories on all- and site-specific (breast, colorectal, lung, prostate, endometrial and hematologic) cancer incidence. Models were adjusted for age, sex (non sex-specific cancers), highest level of education, total household income, marital status, alcohol intake, smoking status, body mass index, family history of cancer, presence of at least one medical condition/co-morbidity, menopausal status (female cancers only) and sleep duration (sleep timing midpoint analysis only). Results: By 2016, there were 3,034 incident cases of cancer in this cohort. A statistical trend was noted for an increased risk of all cancers in participants reporting &amp;gt; 9 hours of sleep/night compared to 7–9 hours of sleep/night (hazard ratio (HR) = 1.16, 95% confidence interval (CI): 0.98–1.36; P = 0.08). Reporting &amp;gt; 9 hours of sleep/night compared to 7–9 hours of sleep/night was also associated with an increased incidence of endometrial cancer (HR = 2.09, 95% CI: 1.16–3.76; P = 0.01). A later sleep timing midpoint (&amp;gt;4:08 AM) versus an intermediate sleep timing midpoint (3:47 AM–4:08 AM) was associated with an increased risk of all (HR = 1.19, 95% CI: 1.03–1.37; P = 0.02) and breast (HR = 1.64, 95% CI: 1.18–2.26; P = 0.003) cancer incidence. Conclusions: These novel findings provide evidence regarding the important role of sleep in cancer etiology. Interventions that put emphasis on proper sleep hygiene for cancer prevention are needed.

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.

Seasonal and weather variation of sleep and physical activity in 12–14-year-old children

ABSTRACT Background: Understanding variation in physical activity (PA) and sleep is necessary to develop novel intervention strategies targeting adolescents’ health behaviors. We examined the extent to which PA and sleep vary by aspects of the physical environment. Participants: We performed a cross-sectional analysis of 669 adolescents in the Project Viva cohort. Methods: We estimated total PA, sleep duration, sleep efficiency, and sleep midpoint timing from wrist accelerometers. We used multivariable linear regression models and generalized estimated equations to assess associations of PA and sleep with season and daily weather conditions obtained from the National Oceanic and Atmospheric Administration archive. Results: Mean age was 12.9 (SD 0.6) years; 51% were female and 68% were white. Mean sleep duration was 466 (SD 42) min per night and total PA was 1,652 (SD 431) counts per min per day. Sleep midpoint time was 41 (95% CI: 27 to 54) min later in summer, 28 (95% CI: −41 to −14) min earlier in spring, and 29 (95% CI: −43 to −15) min earlier in autumn compared to winter. Higher temperature and longer day length both were associated with small reductions of nightly sleep duration. Adolescents were less physically active during winter and on rainy and short sunlight days. There was an inverse U-shaped relationship between PA and mean temperature. Conclusions: Season was associated with large changes in sleep timing, and smaller changes in other sleep and PA measurements. Given the importance of sleep and circadian alignment, future health behavioral interventions may benefit by targeting “season-specific” interventions.