Relationship between sleep duration and cause-specific mortality in diabetic men and women based on self-reports

Sleep and Biological Rhythms - Sleep duration could affect glucose tolerance and mortality. However, the impact that sleep duration has on prognosis of people with diabetes is unclear. A cohort of...     

Cosleeping and sleep problems in children: a systematic review and meta-analysis

Sleep and Biological Rhythms - There exist inconsistent findings about the relation between cosleeping and sleep problems in children. We conducted a meta-analysis to assess these relations and...     

Temporal associations between daytime physical activity and sleep in children

Objectives

We examined temporal associations between objectively-measured physical activity (PA) during the day and in the evening, and sleep quantity and quality.

Study Design

PA and sleep were measured by actigraphs for an average of one week in an epidemiological cohort study of 275 eight-year-old children.

Results

For each one standard deviation (SD) unit of increased PA during the day, sleep duration was decreased by 0.30, sleep efficiency by 0.16, and sleep fragmentation increased by 0.08 SD units that night. For each one SD unit increase in sleep duration and efficiency the preceding night, PA the following day decreased by 0.09 and 0.16 SD units, respectively. When we contrasted days with a high amount of moderate to vigorous activity during the day or in the evening to days with a more sedentary profile, the results were essentially similar. However, moderate to vigorous PA in the evening shortened sleep latency.

Conclusions

The relationship between a higher level of PA and poorer sleep is bidirectional. These within-person findings challenge epidemiological findings showing that more active people report better sleep. Since only a few studies using objective measurements of both PA and sleep have been conducted in children, further studies are needed to confirm/refute these results.     

Relationship between shift work schedule and self-reported sleep quality in Chinese employees

Few studies have reported on the effects of fixed and rotating shift systems on the prevalence of sleep disturbance. Thus, in this study, the relationships between different work schedules and sleep disturbance in Chinese workers were investigated. A total of 2180 workers aged 19–65 years responded to the self-report questionnaire on shift work schedule (fixed day-shift, fixed night-shift, two-shift or three-shift system), working hours a day, and working days a week, physical effort, subjective sleep quality and subjective mental state. It was found that the rotating shift workers, namely, two- and three-shift workers, exhibited higher risks of sleep disturbance than with the fixed day-shift workers did (OR 1.37; 95% CI 1.07to 1.74; and OR 2.19; 95% CI 1.52 to 3.15, respectively). The risk was particularly high among two- or three-shift workers who worked more than 8 hours a day or more than 5 days a week and among three-shift workers who reported both light and heavy physical effort at work. Moreover, the two- and three-shift workers (rotating shift workers) suffered from poorer sleep quality than the fixed night shift workers did (OR 1.84; 95% CI 1.01 to 3.32; and OR 2.94; 95% CI 1.53 to 5.64, respectively). Consequently, rotating shift work (two- and three-shift work) is a risk factor for sleep disturbance, and the fixed work rhythm may contribute to the quality of sleep.     

Correlations between sleep patterns and cardiovascular diseases in a Chinese middle-aged population

Epidemiological and animal studies have suggested an association between habitual sleep patterns and cardiovascular (CV) disease, but the results are still controversial. Therefore, the aims of this study are to investigate the relationships between habitual sleep patterns and CV disease based on Prospective Urban Rural Epidemiology (PURE) China study. PURE China study recruited 46 285 participants, aged 35–70, from 12 provinces and 115 communities in China. Habitual sleep patterns and CV disease were self-reported. Multilevel logistic regression was used in our analysis. In this study, 39 515 participants were eligible in our analysis, including 23 345 (59.1%) women and 16 170 (40.9%) men. Sleeping ≥9 h per day was associated with increased odds of CV disease (OR = 1.16, 95% CI: 1.01–1.32, p = 0.033) compared with sleeping 7–8 h per day. Taking daytime naps was also associated with an increased odds of CV disease, and the CV odds increased with increasing napping duration (p for trend < 0.001). For the sleeping < 6 h per day, we only found an association with coronary artery disease (CAD) (OR = 1.58, 95% CI: 1.01–2.48, p = 0.046). Participants with only 7–8 h sleep per night had lowest prevalence of CV disease (OR = 0.77, 95% CI: 0.65–0.90, p = 0.001) compared with other sleep patterns. Napping, long and short duration of habitual sleep may increase the odds of CV disease. Only participants sleeping 7–8 hours at night are recommended in this study, and large longitudinal studies are needed to confirm these results.     

A study of the association between sleep habits and problematic behaviors in preschool children

This preliminary study examined the association between sleep habits and problematic behaviors in healthy preschool children using an internationally standardized method. Two groups of 4-6-yr-old healthy Japanese children were recruited. Children in Group A (n=68) met one or more of the following three conditions: they went out from their home with adults after 21:00 h two or more times a week, they went to bed after 23:00 h four or more times a week, and they returned home after 21:00 h three or more times a week, while those in Group B (n=67) met none of these conditions. Sleep-wake logs and the Child Behavior Checklist (CBCL)/4-18 were completed daily for two weeks. The CBCL consists of questions with 113 items categorized into eight subscale items: (I) Withdrawn, (II) Somatic complaints, (III) Anxious/depressed, (IV) Social problems, (V) Thought problems, (VI) Attention problems, (VII) Delinquent behavior, and (VIII) Aggressive behavior. Internalizing (I+II+III), externalizing (VII+VIII), and total scale scores were also derived. Generally, the higher the score, the greater the likelihood of problematic behaviors in that scale. We compared both the CBCL scores and distribution of the CBCL score-determined clinical classification of behavior (normal, borderline, and abnormal) between the groups. Correlation coefficients between CBCL scores and each of the seven indices of the studied sleep habits (wake-up times, bedtimes, nocturnal sleep duration, nap duration, total sleep duration, and range of variation in wake-up and bedtime) were also assessed. Group A children showed significantly shorter average nocturnal sleep, nap, and total sleep duration, significantly later average bedtimes and wake-up times, and a significantly greater range of variation in bedtimes and wake-up times than Group B children. The CBCL score of the total scale was significantly higher in Group A than Group B children. The distribution of the clinical classifications of behavior between the two groups showed no significant differences. Although nocturnal sleep, nap, and total sleep duration did not correlate with total CBCL score, it showed a high positive correlation with wake-up times, bedtimes, and ranges of variation in both wake-up and bed times. The distribution of the clinical classification for the total scale showed significant differences between early and late risers, and also between regular and irregular sleepers. The number of children classified as normal for the total scale score was higher in early risers and regular sleepers than in late risers and irregular sleepers. Preschool children of Group A, late risers, late sleepers, irregular risers, and irregular sleepers were likely to show problematic behaviors.     

Prevalent sleep problems in the aged

Quality of sleep influences the level of daytime functioning, including stress levels, psychosomatic complaints, general health, and overall well-being. As people age, they complain more about disturbed sleep, insomnia, increased time in bed, and sleep fragmentation. These complaints can be related to circadian rhythm desynchronization, hypnotic or other medication use, chronic bedrest, napping, dementia, or to sleep apnea, a disorder of respiratory cessation which is quite prevalent in the elderly. We review here the results of 12 years of research on sleep in the elderly. In studies of three populations of elderly, it was found that between 24% and 42% had five or more apneas per hour of sleep and 4%–14% had 20 or more apneas per hour of sleep. Since apnea is related to dementia and even to mortality, this high prevalence of apnea is of extreme importance.Supported by grants Nos. NIA 02711, NIA 08415, NBHLI 40930, RSDA NIMH 00117 (to DFK) and by the Veterans Affairs Research Administration. Special appreciation is given to Dr. Elizabeth Barrett-Connor, Dr. Melville R. Klauber, Robert Fell, William Mason, Linda Parker, and Jennifer Bloomquist for help with these studies.     

Polysomnographic comparison between Chinese and Caucasian patients with obstructive sleep apnea

Sleep and Biological Rhythms - The Chinese population has a comparable prevalence of obstructive sleep apnea (OSA) compared to their Caucasian counterparts, but are notably less obese. Given this...     

Sleep patterns and sleep problems among Egyptian school children living in urban,suburban, and rural areas

The present study was conducted to determine the prevalence of sleep patterns and sleep problems among Egyptian school-aged children and to compare sleep patterns and sleep problems among school children from urban, suburban, and rural areas. In this cross-sectional survey, parents of 629 school-aged children, aged 6 to 10 years, from 15 elementary schools in five rural, urban, and suburban areas in the Giza governorate, Egypt, completed the Arabic version of the Children’s Sleep Habits Questionnaire (CSHQ) and questions about parents’ level of education and significant medical problems and/or medication for the child. The mean (SD) of total sleep duration for all children was 8.96 h (SD, 1.20). The most prevalent CSHQ subscales were: bedtime resistance, daytime sleepiness, and night wakings. There were significant differences regarding bedtime (P= 0.006) and night-time sleep duration (P < 0.001) among school children from different areas, but there were no significant differences regarding wake-up time, total sleep duration, duration of nap, and the eight CSHQ subscale scores. The percentage of children who took a daytime nap was 52.9% (n= 184) and the mean (SD) duration of a nap was 1.5 h (SD, 0.92). Paternal illiteracy was associated with higher CSHQ total score and many subscales. In conclusion, sleep duration was shorter than that reported in previous studies. Sleep problems are fairly common among elementary school children in the Giza governorate, whether in urban, suburban, or rural areas. Paternal level of education has an impact on the prevalence of sleep problems.

     

The relationships between self-efficacy,self-control,chronotype, procrastination and sleep problems in young adults

ABSTRACT

The main aim of our study was to examine whether there was a relationship between psychological characteristics such as self-efficacy, self-control and chronotype as well as procrastination on the one hand and sleep problems on the other. There were 315 young adults aged between 18 and 27 years (M = 20.57). We used the General Procrastination Scale, the General Self-Efficacy Scale (GSES), Brief Self-Control Scale, the Composite Scale of Morningness (CSM) and the Pittsburgh Sleep Quality Index (PSQI). Our results indicated that low self-efficacy, low self-control and eveningness were positive predictors of procrastination. The reciprocal relationship exists between procrastination and sleep problems. Procrastination positively contributed to sleep problems, whereas sleep problems were a negative predictor of procrastination.     

Prevalent sleep problems in the aged.

Quality of sleep influences the level of daytime functioning, including stress levels, psychosomatic complaints, general health, and overall well-being. As people age, they complain more about disturbed sleep, insomnia, increased time in bed, and sleep fragmentation. These complaints can be related to circadian rhythm desynchronization, hypnotic or other medication use, chronic bedrest, napping, dementia, or to sleep apnea, a disorder of respiratory cessation which is quite prevalent in the elderly. We review here the results of 12 years of research on sleep in the elderly. In studies of three populations of elderly, it was found that between 24% and 42% had five or more apneas per hour of sleep and 4%-14% had 20 or more apneas per hour of sleep. Since apnea is related to dementia and even to mortality, this high prevalence of apnea is of extreme importance.     

Arousal and ventilatory responses during sleep in children with obstructive sleep apnea

Abnormal centralregulation of upper airway muscles may contribute to thepathophysiology of the childhood obstructive sleep apnea syndrome(OSAS). We hypothesized that this was secondary to global abnormalitiesof ventilatory control during sleep. We therefore compared the responseto chemical stimuli during sleep between prepubertal children with OSASand controls. Patients with OSAS aroused at a higherPCO₂ (58 ± 2 vs. 60 ± 5 Torr,P < 0.05); those with the highestapnea index had the highest arousal threshold(r = 0.52, P < 0.05). The hypercapnic arousal threshold decreased after treatment. For all subjects, hypoxia was apoor stimulus to arousal, whereas hypercapnia and, particularly, hypoxic hypercapnia were potent stimuli to arousal. Hypercapnia resulted in decreased airway obstruction in OSAS. Ventilatory responseswere similar between patients with OSAS and controls; however, thesample size was small. We conclude that children with OSAS haveslightly blunted arousal responses to hypercapnia. However, the overallventilatory and arousal responses are normal in children with OSAS,indicating that a global deficit in respiratory drive is not a majorfactor in the etiology of childhood OSAS. Nevertheless, subtleabnormalities in ventilatory control may exist.

     

Sleep-health care and education are urgently needed for excessive screen time and sleep problems among school-age children

Sleep and Biological Rhythms -     

Agreement between theory and measurement in quantification of ammonia-oxidizing bacteria

Autotrophic ammonia-oxidizing bacteria (AOB) are of vital importance to wastewater treatment plants (WWTP), as well as being an intriguing group of microorganisms in their own right. To date, corroboration of quantitative measurements of AOB by fluorescence in situ hybridization (FISH) has relied on assessment of the ammonia oxidation rate per cell, relative to published values for cultured AOB. Validation of cell counts on the basis of substrate transformation rates is problematic, however, because published cell-specific ammonia oxidation rates vary by over two orders of magnitude. We present a method that uses FISH in conjunction with confocal scanning laser microscopy to quantify AOB in WWTP, where AOB are typically observed as microcolonies. The method is comparatively simple, requiring neither detailed cell counts or image analysis, and yet it can give estimates of either cell numbers or biomass. Microcolony volume and diameter were found to have a log-normal distribution. We were able to show that virtually all (>96%) of the AOB biomass occurred as microcolonies. Counts of microcolony abundance and measurement of their diameter coupled with a calibration of microcolony dimensions against cell numbers or AOB biomass were used to determine AOB cell numbers and biomass in WWTP. Cell-specific ammonia oxidation rates varied between plants by over three orders of magnitude, suggesting that cell-specific ammonia oxidation is an important process variable. Moreover, when measured AOB biomass was compared with process-based estimates of AOB biomass, the two values were in agreement.