Exploration of Sex and Age as Moderators Between Social Cumulative Risk and Sleep in a Representative Sample of Children and Adolescents Living in the United States.

BACKGROUND: Youth who face adversity are at a disproportionate risk for poor sleep health across the life course. Identifying whether the association between adversity and poor sleep varies based upon age and sex is needed. This study aims to explore sex and age as moderators between social risk and sleep in a sample of U.S. youth. METHODS: This study analyzed data of 32,212 U.S. youth (6-17 years) whose primary caregiver participated in the 2017-2018 National Survey of Children's Health. A social cumulative risk index (SCRI) score was calculated from 10 parental, family, and community risk indicators. Nighttime sleep duration was the number of hours the child slept during the past week. Weeknight sleep irregularity was operationalized as whether the child sometimes/rarely/never went to bed at the same time. Generalized logistic regression models estimated associations between SCRI and sleep duration/irregularity, with age and sex as moderators. RESULTS: Age moderated the association between SCRI and short sleep (OR = 1.12, p < 0.001), such that the magnitude of the SCRI-sleep relationship was 12% greater in school-age children. Sex was not a significant moderator. In stratified models by age group, age was positively associated with short sleep in both groups, with a greater magnitude in school-age children. Female school-age children were less likely to have short sleep than males. CONCLUSIONS: Younger children with greater social cumulative risk factors may be more vulnerable to short sleep duration. Further research into the mechanisms underlying the relationships between social risk and sleep health in school-age children is needed.

Sleep Variability, Sleep Irregularity, and Nighttime Blood Pressure Dipping.

BACKGROUND: Circadian rhythm regulates many important biological functions in humans. The goal of this study is to explore the impact of day-to-day deviations in the sleep-wake cycle on nighttime blood pressure (BP) dipping and further examine whether the ethnic difference in day-to-day deviations in sleep patterns can explain the ethnic difference in nighttime BP dipping. METHODS: Twenty-four-hour ambulatory BP monitoring and 7-day accelerometer data were obtained from 365 adult participants (age range, 18.7-50.1 years; 52.6% Black participants and 47.3% European Americans; 64.1% females). Systolic BP dipping level was used to represent nighttime BP dipping. The SD of sleep duration was calculated as the index of sleep variability, and the SD of sleep midpoint was calculated as the index of sleep irregularity. RESULTS: A 1-hour increase in the SD of sleep midpoint was associated with a 1.16% decrease in nighttime BP dipping (P<0.001). A 1-hour increase in the SD of sleep duration was associated with a 1.39% decrease in nighttime BP dipping (P=0.017). The ethnic difference in the SD of sleep midpoint can explain 29.2% of the ethnicity difference in BP dipping (P=0.008). CONCLUSIONS: Sleep variability and sleep irregularity are associated with blunted BP dipping in the general population. In addition, data from the present investigation also demonstrate that the ethnic difference in sleep irregularity could partly explain the ethnic difference in BP dipping, an important finding that may help reduce the health disparity between Black participants and European Americans.

Subjective irregular sleep is associated with metabolic syndrome: A cross-sectional study.

Several studies have been reported that sleep duration and circadian rhythms are associated with metabolic syndrome (MetS). However, there are few studies of a relationship between sleep and MetS based on subjective evaluation of sleep regularity. The aim of this study is to examine the relationship between subjective sleep irregularity and metabolic syndrome. This cross-sectional study included 3,880 participants (1,383 males, 2,497 females) from 2013 to 2017, and we use a self-administered questionnaire to acquire information about sleep (sleep regularity, duration and bedtime). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression analyses to evaluate the associations between sleep regularity and the prevalence of MetS. The irregularity of sleep was significantly associated with MetS (OR 1.231, 95% CI 1.101-1.375) adjusted for age, sex, METs, sleep duration, bedtime, drinking and smoking statuses, and a history of using sleeping pills. We examined the interaction of MetS with sleep regularity and sleep duration/bedtime, stratified by multiplying the two groups of sleep regularity/irregularity and the three groups of sleep duration/bedtime. Each group of sleep duration/bedtime showed no relationship in the sleep regularity group with MetS, but a significant relationship in the sleep irregularity group. Leptin was significantly elevated in the irregular sleep group regardless of sleep duration and bedtime. Although many studies have shown a link between sleep and MetS especially in terms of sleep duration, this study showed that irregular sleep is more strongly associated with MetS than sleep duration or bedtime.

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

STUDY OBJECTIVES: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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. CITATION: Katamreddy A, Uppal D, Ramani G, et al. Day-to-day variation in sleep duration is associated with increased all-cause mortality. J Clin Sleep Med. 2022;18(3):921-926.

Social, Biological and Behavioral Factors Associated with Social Jet Lag and Sleep Duration in University Students from a Low Urbanized City.

INTRODUCTION: Sleep deprivation and social jet lag are observed in college students from highly urbanized cities. However, does these consequences also present in college students from a low urbanization city? OBJECTIVE: To evaluate the prevalence and social, biological and behavioral factors associated with sleep deprivation and social jet lag in university students from a low urbanized city of Brazil. METHODS: A total of 298 university students participated in the study through application of the Health and Sleep and the Munich Chronotype Questionnaires. Multiple linear regression with stepwise-forward method was adopted to assess the associations of the factors with the outcome variables. RESULTS: Doing leisure activities (LA) (B = 23.24) and academic demand (AD) before bedtime (B = 19.51), both on the weekend, and doing household chores (HC) before bedtime (B = 17.61) in the week were associated with an increase in social jet lag, while stimulating drinks (SD) were associated with a decrease (B = -15.17). Shorter sleep duration in the week was related to chronotype (B = -0.56), male (B = -26.51), doing LA (B = -27.63), poor perception about sleeping place (PPSP) (B = -43.02) and daily commute (B = -68.97). The shorter sleep duration in the weekend was associated to male (B = -36.36), PPSP (B = -58.16), have recreational and religious activities (B = -31.11), doing LA (B = -25.10) and AD (B = -23.60). Just chronotype was associated with longer sleep duration in the weekend (B = 0.25). CONCLUSION: University students from a low urbanized city present social jet lag, shorter sleep duration on school days and longer sleep duration on free days as a result of biological and social factors, and mostly behavioral factors.

The mediating effect of cognitive appraisal on the relationship between sleep habits and the stress response among Japanese female college students.

BACKGROUND: Undergraduate students tend to develop "evening-type" sleep patterns. Recent research has reported that evening-type and irregular sleep habits are related to physical and mental stress responses, particularly in female students. Although the connection between sleep habits and the stress response has been well documented, the mechanism behind this relationship is currently unknown. Using the transactional model as a framework and female students as our target population, we examined whether sleep habits predict the stress response through the mediation of cognitive appraisals of one's own sleep habits. METHODS: Three hundred twenty-one Japanese female college students participated in this study. Participants completed measures of their sleep habits (sleep patterns and sleep irregularity), cognitive appraisals of their sleep habits (including four subscales: commitment, appraisal of influence, appraisal of threat, and controllability), stress responses (depression and anxiety), and control factors. The reliability and validity of the scales used in this study, except for sleep pattern and sleep irregularity, were confirmed in previous studies. RESULTS: Multiple-mediation-model analysis indicated that commitment mediates the relationship between sleep pattern and anxiety. Meanwhile, cognitive appraisals, as a whole, were found to have a mediating effect on the relationship between sleep irregularity and depression. CONCLUSIONS: Our study revealed that cognitive appraisals mediated the relationship between sleep habits and the stress response. The findings also suggest that maintaining a low level of commitment might be effective for reducing anxiety, especially considering the difficulty associated with changing lifestyles. The findings of the present study should be useful for health education related to lifestyle.

Sleep Irregularity in the Previous Week Influences the First-Night Effect in Polysomnographic Studies.

OBJECTIVE: The first-night effect is a well-known phenomenon resulting from an individual's maladaptation to the unfamiliar environment of a sleep laboratory. However, there have been no direct reports of the effect of previous sleep patterns on the first-night effect. We aimed to investigate the effect the previous week's sleep pattern on the first-night effect. METHODS: Twenty-four young, healthy, male participants completed the study procedure. During one week prior to study, the participants kept sleep diaries and wore actigraphs to identify sleep-wake pattern. Two consecutive nights of polysomnography were conducted after that. Wilcoxon signed-rank tests were applied to compare sleep variables of the two nights. Variance (standard deviation) of sleep onset time during the previous week was used as an index of irregularity. A Kendall's ranked correlation analysis and a linear regression test were applied to detect correlation between sleep irregularity and the first-night effect measured by polysomnography. RESULTS: There were significant differences in the values of sleep efficiency (p=0.011) and wake after sleep onset (WASO) (p=0.006) between the two nights. Sleep efficiency was lower and WASO was higher on the first night as compared to the second night. Sleep irregularity in the previous week was negatively correlated with sleep efficiency (p<0.001) of the first night, but was not significantly correlated with any other sleep parameters. CONCLUSION: We replicated the existence of the first-night effect commonly observed in sleep studies. Sleep irregularity in the previous week may influence the first-night effect in polysomnographic studies.