Long Working Hours and Sleep Disturbances: The Whitehall II Prospective Cohort Study

Study Objective:

To examine whether exposure to long working hours predicts various forms of sleep disturbance; short sleep, difficulty falling asleep, frequent waking, early waking and waking without feeling refreshed.

Design:

Prospective study with 2 measurements of working hours (phase 3, 1991–1994 and phase 5, 1997–1999) and 2 measurements of subjective sleep disturbances (phase 5 and phase 7, 2002–2004).

Setting:

The Whitehall II study of British civil servants.

Participants:

Full time workers free of sleep disturbances at phase 5 and employed at phases 5 and 7 (n = 937–1594) or at phases 3, 5, and 7 (n = 886–1510).

Measurements and Results:

Working more than 55 hours a week, compared with working 35–40 hours a week, was related to incident sleep disturbances; demographics-adjusted odds ratio (95% CI) 1.98 (1.05, 3.76) for shortened sleeping hours, 3.68 (1.58, 8.58) for difficulty falling asleep; and 1.98 (1.04, 3.77) for waking without feeling refreshed. Repeat exposure to long working hours was associated with odds ratio 3.24 (1.45, 7.27) for shortened sleep, 6.66 (2.64, 16.83) for difficulty falling asleep, and 2.23 (1.16, 4.31) for early morning awakenings. Some associations were attenuated after adjustment for other risk factors. To a great extent, similar results were obtained using working hours as a continuous variable. Imputation of missing values supported the findings on shortened sleep and difficulty in falling asleep.

Conclusion:

Working long hours appears to be a risk factor for the development of shortened sleeping hours and difficulty falling asleep.

Citation:

Virtanen M; Ferrie JE; Vahtera J; Elovainio M; Singh-Manoux A; Marmot MG; Kivimäki M. Long working hours and sleep disturbances: the whitehall II prospective cohort study. SLEEP 2009;32(6):737–745.     

The Effect of Short Sleep Duration on Coronary Heart Disease Risk is Greatest Among Those with Sleep Disturbance: A Prospective Study from the Whitehall II Cohort

Study Objectives:

Short sleep duration is associated with increased CHD (coronary heart disease) mortality and morbidity, although some evidence suggests that sleep disturbance is just as important. We investigated whether a combination of short sleep duration and sleep disturbance is associated with a higher risk of CHD than their additive effects.

Setting:

The Whitehall II study.

Patients or Participants:

The Whitehall II study recruited 10,308 participants from 20 civil service departments in London, England. Participants were between the ages of 35 and 55 years at baseline (1985-1988) and were followed up for an average of 15 years.

Interventions:

N/A.

Measurements:

Sleep hours and sleep disturbance (from the General Heath Questionnaire-30) were obtained from the baseline survey. CHD events included fatal CHD deaths or incident nonfatal myocardial infarction or angina (ICD-9 codes 410-414 or ICD-10 I20-25).

Results:

Short sleep duration and sleep disturbance were both associated with increased hazards for CHD in women as well as in men, although, after we adjusted for confounders, only those reporting sleep disturbance had a raised risk. There was some evidence for an interaction between sleep duration and sleep disturbance. Participants with short sleep duration and restless disturbed nights had the highest hazard ratios (HR) of CHD (relative risk:1.55, 95% confidence interval:1.33-1.81). Among participants who did not report any sleep disturbance, there was little evidence that short sleep hours increased CHD risk.

Conclusion:

The effect of short sleep (≤ 6 hours) on increasing CHD risk is greatest among those who reported some sleep disturbance. However, among participants who did not report any sleep disturbance, there was little evidence that short sleep hours increased CHD risk.

Citation:

Chandola T; Ferrie JE; Perski A; Akbaraly T; Marmot MG. The effect of short sleep duration on coronary heart disease risk is greatest among those with sleep disturbance: a prospective study from the Whitehall II cohort. SLEEP 2010;33(6):739-744     

Coping with Sleep Disturbances Among Young Adults: A Survey of First-Year College Students in Taiwan

Abstract

Sleep problems are highly prevalent among young adults and affect different aspects of their quality of life. In this study, the authors aimed to investigate the young adults' coping strategies for these sleep disturbances and the effectiveness of the coping strategies upon sleep quality and daytime sleepiness. The subjects included 1,922 first-year college students, 44% of whom reported experiencing sleep problems, with insufficient sleep being the most common complaint (23.9%). Taking naps and adjusting sleep schedules were the coping strategies associated with better sleep quality. On the other hand, subjects who reported attempting a sleep-promoting activity, ignoring their sleep problems altogether, or trying unsuccessfully to find a way of coping with their sleep problems reported a poorer sleep quality. Although some coping strategies were associated with better sleep quality than others, the levels of daytime sleepiness were equally impaired in all coping groups to a degree that is equivalent to the sleepiness in patients with a moderate sleep-related breathing disorder.     

Habitual Sleep Duration and Insomnia and the Risk of Cardiovascular Events and All-cause Death: Report from a Community-Based Cohort

Study Objectives:

To investigate the relationship between sleep duration and insomnia severity and the risk of all-cause death and cardiovascular disease (CVD) events

Design:

Prospective cohort study

Setting:

Community-based

Participants:

A total of 3,430 adults aged 35 years or older

Intervention:

None

Measurements and Results:

During a median 15.9 year (interquartile range, 13.1 to 16.9) follow-up period, 420 cases developed cardiovascular disease and 901 cases died. A U-shape association between sleep duration and all-cause death was found: the age and gender-adjusted relative risks (95% confidence interval [CI]) of all-cause death (with 7 h of daily sleep being considered for the reference group) for individuals reporting ≤ 5 h, 6 h, 8 h, and ≥ 9 h were 1.15 (0.91–1.45), 1.02 (0.85–1.25), 1.05 (0.88–1.27), and 1.43 (1.16–1.75); P for trend, 0.019. However, the relationship between sleep duration and risk of CVD were linear. The multivariate-adjusted relative risk (95% CI) for all-cause death (using individuals without insomnia) were 1.02 (0.86–1.20) for occasional insomnia, 1.15 (0.92–1.42) for frequent insomnia, and 1.70 (1.16–2.49) for nearly everyday insomnia (P for trend, 0.028). The multivariate adjusted relative risk (95% CI) was 2.53 (1.71–3.76) for all-cause death and 2.07 (1.11–3.85) for CVD rate in participants sleeping ≥9 h and for those with frequent insomnia.

Conclusions:

Sleep duration and insomnia severity were associated with all-cause death and CVD events among ethnic Chinese in Taiwan. Our data indicate that an optimal sleep duration (7–8 h) predicted fewer deaths.

Citation:

Chien K; Chen P; Hsu H; Su T; Sung F; Chen M; Lee Y. Habitual sleep duration and insomnia and the risk of cardiovascular events and all-cause death: report from a community-based cohort. SLEEP 2010;33(2):177–184.     

Insomnia with Short Sleep Duration and Mortality: The Penn State Cohort

Study Objectives:

Because insomnia with objective short sleep duration is associated with increased morbidity, we examined the effects of this insomnia subtype on all-cause mortality.

Design:

Longitudinal.

Setting:

Sleep laboratory.

Participants:

1,741 men and women randomly selected from Central Pennsylvania.

Measurements:

Participants were studied in the sleep laboratory and were followed-up for 14 years (men) and 10 years (women). “Insomnia” was defined by a complaint of insomnia with duration ≥ 1 year. “Normal sleeping” was defined as absence of insomnia. Polysomnographic sleep duration was classified into two categories: the “normal sleep duration group” subjects who slept ≥ 6 h and the “short sleep duration group” subjects who slept < 6 h. We adjusted for age, race, education, body mass index, smoking, alcohol, depression, sleep disordered breathing, and sampling weight.

Results:

The mortality rate was 21% for men and 5% for women. In men, mortality risk was significantly increased in insomniacs who slept less than 6 hours compared to the “normal sleep duration, no insomnia” group, (OR = 4.00, CI 1.14-13.99) after adjusting for diabetes, hypertension, and other confounders. Furthermore, there was a marginally significant trend (P = 0.15) towards higher mortality risk from insomnia and short sleep in patients with diabetes or hypertension (OR = 7.17, 95% CI 1.41-36.62) than in those without these comorbid conditions (OR = 1.45, 95% CI 0.13-16.14). In women, mortality was not associated with insomnia and short sleep duration.

Conclusions:

Insomnia with objective short sleep duration in men is associated with increased mortality, a risk that has been underestimated.

Citation:

Vgontzas AN; Liao D; Pejovic S; Calhoun S; Karataraki M; Basta M; Fernández-Mendoza J; Bixler EO. Insomnia with short sleep duration and mortality: the Penn State Cohort. SLEEP 2010;33(9):1159-1164.     

Development of sleep patterns in early adolescence

This study examines the developmental changes of sleep patterns as a function of gender and puberty and assesses the prevalence of sleep habits and sleep disturbances in early adolescence. It also investigates the relationship between sleep patterns, sleep habits and difficulty falling asleep and nocturnal awakenings. The present analyses are based on results available for 588 boys and 558 girls for whom mothers completed questions concerning demographics and sleep at annual intervals when their child was aged 10--13 years. The results indicated that nocturnal sleep times decreased, bedtimes were delayed and differences between weekend and school day sleep schedules progressively increased with age. Gender and puberty were both associated with the timing of sleep on weekends. Girls presented longer weekend time in bed (TIB) and later weekend wake time than boys. Similarly, subjects with higher pubertal status showed longer weekend TIB and later weekend wake time than subjects with lower pubertal status. Difficulty falling asleep was associated with later weekend wake time and with sleeping with a night light. In conclusion, the gender differences commonly reported in adolescents' sleep patterns are most likely explained by girls' higher pubertal status. This study emphasizes the link between puberty and a putative physiological need for more sleep, in presence of a general reduction of sleep times during adolescence. From age 10--13 years, the delay and lengthening of the sleep period on weekends in comparison to schooldays is associated with difficulty falling asleep.     

Sleep Disturbances in Prepubertal Children with Attention Deficit Hyperactivity Disorder: A Home Polysomnography Study

Study Objectives:

To examine sleep architecture and reported sleep problems in children with ADHD and normal controls, while considering the roles of pertinent moderating factors.

Design:

Overnight sleep recordings were conducted in 15 children diagnosed with ADHD (DSM-IV) without comorbid psychiatric problems and in 23 healthy controls aged 7 to 11 years. Children were on no medication, in good health and did not consume products containing caffeine ≥ 7 days prior to the polysomnography (PSG) study. PSG evaluation was performed at each child''s home; children slept in their regular beds and went to bed at their habitual bedtimes.

Measurements

Standard overnight multichannel PSG evaluation was performed using a portable polysomnography device. In addition, parents were asked to complete a sleep questionnaire.

Results:

Compared to controls, children in the ADHD group had significantly shorter duration of REM sleep, smaller percentage of total sleep time spent in REM sleep, and shorter sleep duration. In addition, the ADHD group had higher scores on the insufficient sleep and sleep anxiety factors than children in the control group.

Conclusions:

The present findings support the hypothesis that children with ADHD present sleep disturbances.

Citation:

Gruber R; Xi T; Frenette S; Robert M; Vannasinh P; Carrier J. Sleep disturbances in prepubertal children with attention deficit hyperactivity disorder: A home polysomnography study. SLEEP 2009;32(3):343-350.     

Polysomnographic indicators of restorative sleep and body mass trajectories in the Wisconsin Sleep Cohort Study

Study ObjectivesPrevious research suggests that reductions in restorative, slow-wave (N3), and rapid eye movement (REM) sleep are associated with weight gain and obesity in mid-to-late life. We extend prior work by examining how within-person (WP) changes and between-person (BP) differences in restorative sleep over several years are associated with body mass trajectories among participants in the Wisconsin Sleep Cohort Study (WSCS).MethodsWe used data from 4,862 polysomnographic (PSG) sleep studies and physical exams collected from 1,187 WSCS participants over an average duration of 14.9 years. Primary measures of interest included body mass index (BMI = kg/m²) and the percentages of time spent in N3 and REM sleep. We estimated a series of linear mixed regression models to examine how WP changes and BP differences in N3 and REM sleep affected BMI trajectories, controlling for other sleep measures, demographic characteristics, and health behaviors as potential confounders.ResultsWomen in the WSCS experienced more rapid BMI gain than men. With some variation by sex, we found that (1) below-average N3 and REM sleep is associated with above-average BMI, and (2) within-person decreases in N3 and REM sleep over time are associated with gains in BMI. These findings persisted after adjustment for sleep duration and other potential confounders.ConclusionsOur findings highlight the importance of PSG indices of restorative sleep in mid-to-late life, suggesting that future clinical treatments and public health policies will benefit from heightened attention to sleep quality.     

Workplace Bullying and Sleep Disturbances: Findings from a Large Scale Cross-Sectional Survey in the French Working Population

Study Objectives:

The purpose of this study was to explore the associations between workplace bullying, the characteristics of workplace bullying, and sleep disturbances in a large sample of employees of the French working population.

Design:

Workplace bullying, evaluated using the validated instrument developed by Leymann, and sleep disturbances, as well as covariates, were measured using a self-administered questionnaire. Covariates included age, marital status, presence of children, education, occupation, working hours, night work, physical and chemical exposures at work, self-reported health, and depressive symptoms. Statistical analysis was performed using logistic regression analysis and was carried out separately for men and women.

Setting:

General working population.

Participants:

The study population consisted of a random sample of 3132 men and 4562 women of the working population in the southeast of France.

Results:

Workplace bullying was strongly associated with sleep disturbances. Past exposure to bullying also increased the risk for this outcome. The more frequent the exposure to bullying, the higher the risk of experiencing sleep disturbances. Observing someone else being bullied in the workplace was also associated with the outcome. Adjustment for covariates did not modify the results. Additional adjustment for self-reported health and depressive symptoms diminished the magnitude of the associations that remained significant.

Conclusions:

The prevalence of workplace bullying (around 10%) was found to be high in this study as well was the impact of this major job-related stressor on sleep disturbances. Although no conclusion about causality could be drawn from this cross-sectional study, the findings suggest that the contribution of workplace bullying to the burden of sleep disturbances may be substantial.

Citation:

Niedhammer I; David S; Degioanni S; Drummond A; Philip P. Workplace bullying and sleep disturbances: findings from a large scale cross-sectional survey in the French working population. SLEEP 2009;32(9):1211-1219.     

睡眠剥夺影响执行控制的功能磁共振成像研究

目的: 探讨完全睡眠剥夺(total sleep deprivation,TSD)对大脑执行控制功能的影响.方法: 采用自身前后对照设计.以13名健康男性大学生作为被试,进行两次Go/No-go测验,同时进行功能磁共振成像(functional magnetic resonance imaging,fMRI)扫描,第一次在正常睡眠后12小时完成,第2次间隔3周在睡眠剥夺36小时后完成.结果: 与睡眠后的Co/No-go测试成绩相比,睡眠剥夺后被试的正确击中率下降[(0.99±0.01)vs.(0.97±0.04),P＜0.05)],错误反应率增高[(0.04±0.04)vs.(0.10±0.08),P＜0.05].fMRI结果显示前扣带回皮质活动降低[(-0.391±0.003)vs.0;P＜0.05],前额叶皮质活动明显增强[(0.653±0.003)vs.0;P＜0.05].结论: 睡眠剥夺36小时导致执行抑制功能的显著下降,前额叶皮质出现功能代偿是维持认知作业的重要特征.     

Sleep duration and sleep disturbances partly explain the association between depressive symptoms and cardiovascular mortality: the Whitehall II cohort study

Depressive symptoms are associated with an increased risk of death, but most of this association remains unexplained. Our aim was to explore the contribution of sleep duration and disturbances to the association between depressive symptoms, all‐cause and cardiovascular disease mortality. A total of 5813 (4220 men and 1593 women) aged 50–74 years at baseline, participants of the British Whitehall II prospective cohort study, were included. Depressive symptoms, sleep duration and disturbances were assessed in 2003–04. Mortality was ascertained through linkage to the national mortality register until August 2012, with a mean follow‐up of 8.8 years. Depressive symptoms were associated with an increased risk of mortality from all causes [hazard ratio (HR) = 1.51; 95% confidence interval (CI): 1.16–1.97)] and cardiovascular diseases (HR = 1.63; 95% CI: 1.01–2.64) after adjustment for sociodemographic characteristics. Further adjustment for sleep duration and disturbances reduced the association between depressive symptoms and cardiovascular mortality by 21% (HR = 1.53; 95% CI: 0.91–2.57). Sleep seems to have a role, as a mediator or confounder, in explaining the association between depressive symptoms and cardiovascular mortality. These findings need replication in larger studies with longer follow‐up.     

社会支持与网络成瘾关系的队列研究

目的：探讨社会支持与大学生网络成瘾的关系。方法：在某大学2000级医科类学生中以整群随机抽样的方法随机抽取10个小班382名学生为研究对象，分别以其进校第一学期末的社会支持与领悟社会支持得分的四分位数作为分界点，将研究对象分为社会支持低、中、高组，比较社会支持得分不同者毕业时网络成瘾检出率。结果：不论是按社会支持总分、领悟社会支持总分的高低分组，还是按两量表的各维度分的高低分组，社会支持得分低者网络成瘾的发生率均较社会支持评分高者高（领悟社会支持总分0～60、61～73、≥73者网络成瘾检出率分别为15．7％、7．9％、2．4％，χ^2=9．49，P=0．009）网络成瘾检出率与社会支持总分及各维度得分均呈剂量反应关系。结论：较少的社会支持是大学生网络成瘾的危险因素。     

Dietary Patterns Only Partially Explain the Effect of Short Sleep Duration on the Incidence of Obesity

Study Objectives:

To investigate whether dietary patterns explain the possible association between short sleep duration and obesity.

Design:

Longitudinal study.

Setting:

Annual health checkup at a Japanese workplace over a 4-year period from 1994-1995 (baseline) to 1998-1999 (follow-up).

Participants:

Nonobese Japanese male workers aged 40 to 59 years (n = 2632)

Measurements and Results:

Trained health professionals conducted a questionnaire-based survey. Preference for fatty food, skipping breakfast, and eating out were significantly associated with short sleep duration. Snacking and preference for fatty food significantly predicted the incidence of obesity, which was defined as a body mass index of at least 25 kg/m². Hierarchic logistic regression analyses were conducted to test the significance of the association between sleep duration and the incidence of obesity, before and after controlling for covariates, including dietary patterns (preference for fatty food, skipping breakfast, snacking, and eating out). Participants who slept less than 6 hours were compared with those who slept 7.0 to 7.9 hours. The odds ratio for the incidence of obesity was 2.55 (95% confidence interval [CI] 1.48, 4.42; trend P = 0.007) with covariate adjustment, except for dietary patterns, and 2.46 (95% CI 1.41, 4.31; trend P = 0.011) with complete adjustment, including dietary patterns.

Conclusions:

Preference for fatty food, skipping breakfast, snacking, and eating out only partially explained the effects of short sleep duration on the incidence of obesity, suggesting that other factors, including physiologic mechanisms, may largely explain the sleep-obesity association.

Citation:

Nishiura C; Noguchi J; Hashimoto H. Dietary patterns only partially explain the effect of short sleep duration on the incidence of obesity. SLEEP 2010;33(6):753-757.     

Sleep disturbances in Rett syndrome: Impact and management including use of sleep hygiene practices

Sleep disturbances are debilitating for individuals with Rett syndrome (RTT) and their families yet the evidence base for management is poor. We investigated management strategies and their relationships with sleep problems. Data were provided by 364/461 (79%) families with a child with RTT and registered with the International RTT Phenotype Database. Logistic regression models were used to investigate relationships between impacts of sleep problems on the child and family with age group, mutation type, medication type, and sleep hygiene score. Linear regression models were used to estimate the association of disorders of initiating and maintaining sleep (DIMS) with age group, mutation type, medication type, and sleep hygiene. Among those who ever had difficulty falling asleep or night waking, use of any medication was associated with higher odds of moderate/major impact sleep problems (relative to minor/no impact) for the affected child and the family, as well as higher DIMS scores, when compared with the no treatment/nonmedication group accounting for the effects of age, mutation type, and sleep hygiene score. Better use of sleep hygiene practices was associated with lower odds of moderate/major impact on the family (odds ratio 0.60, 95% confidence intervals [CIs] 0.37, 0.98) and lower DIMS scores (geometric mean ratio 0.86, 95%CI 0.80, 0.92) compared with poorer use after adjusting for covariates. Attention to sleep hygiene remains an important management strategy for sleep problems in RTT. Further prospective research is required to investigate efficacy of pharmaceutical treatments.     

一起诺如病毒性胃肠炎暴发的队列研究

目的调查分析某村一起诺如病毒性胃肠炎暴发的发病原因。方法采用历史性队列研究方法，应用ELISA对标本进行实验室检测。结果该起暴发共报告病例34例，发病与接触腹泻病人（X^2=6．51，P=0．00）、食物暴露于苍蝇（X^2=4．61，P=0．00）及村民暴露于患者呕吐物或粪便1m内（X^2=3．09，P=0．00）有统计学意义上的关联，与饮用水来源（X^2=1．68，P=0．14）没有统计学意义上的关联。在采集的8份肛拭子样本中1份ELISA法检出诺如病毒抗原阳性：4份粪便样本中2份ELISA法检出诺如病毒抗原阳性。结论这是一起由诺如病毒感染所致的急性胃肠炎暴发．密切接触是此次暴发的主要传播途径。     

Validation of a French version of the Sleep Condition Indicator: a clinical screening tool for insomnia disorder according to DSM‐5 criteria

Insomnia disorder is frequent in the population, yet there is no French screening instrument available that is based on the updated DSM‐5 criteria. We evaluated the validity and reliability of the French version of an insomnia screening instrument based on DSM‐5 criteria, the Sleep Condition Indicator, in a population‐based sample of adults. A total of 366 community‐dwelling participants completed a face‐to‐face clinical interview to determine insomnia disorder against DSM‐5 criteria and several questionnaires including the French Sleep Condition Indicator version. Three‐hundred and twenty‐nine participants completed the Sleep Condition Indicator again after 1 month. Statistical analyses were performed to determine the reliability, construct validity, divergent validity and temporal stability of the French translation of the Sleep Condition Indicator. In addition, an explanatory factor analysis was performed to assess the underlying structure. The internal consistency (α = 0.87) and temporal stability (r = 0.86, P < 0.001) of the French Sleep Condition Indicator were high. When using the previously defined cut‐off value of ≤ 16, the area under the receiver operating characteristic curve was 0.93 with a sensitivity of 95% and a specificity of 75%. Additionally, good construct and divergent validity were demonstrated. The factor analyses showed a two‐factor structure with a focus on sleep and daytime effects. The French version of the Sleep Condition Indicator demonstrates satisfactory psychometric properties while being a useful instrument in detecting cases of insomnia disorder, consistent with features of DSM‐5, in the general population.     

Long-Term Aspirin Use and 5-Year Survival in Healthy Adults: A Population-Based Cohort Study in South Korea

PurposeWe investigated whether long-term aspirin use is associated with 5-year all-cause mortality.Materials and MethodsParticipants were individuals aged ≥40 years who were registered in the 2010 sample cohort database of the National Health Insurance Service in South Korea. Aspirin users were divided into three groups: continuous users (2006–2010), previous users (2006–2009), and new users (2010). Individuals with a history of coronary artery disease and cerebrovascular disease were excluded. Five-year all-cause mortality was defined as mortality due to any cause from January 1, 2011 to December 31, 2015. Data were analyzed by multivariable Cox regression.ResultsIn total, 424444 individuals were included. Five-year all-cause mortality was 9% lower in continuous aspirin users than in unexposed individuals [hazard ratio (HR): 0.91, 95% confidence interval (CI): 0.86–0.97; p=0.003]. Five-year all-cause mortality rates in the new aspirin users (HR: 1.00, 95% CI: 0.90–1.11; p=0.995) and previous aspirin users (HR: 1.01, 95% CI: 0.94–1.09; p=0.776) were not significantly different from that in unexposed individuals. In the 40–60-year age group, 5-year all-cause mortality in the continuous aspirin users was 24% lower (HR: 0.76, 95% CI: 0.64–0.90; p=0.002) than that in unexposed individuals. However, in the >60-year age group, there was no significant association between aspirin use and 5-year all-cause mortality (HR: 0.96, 95% CI: 0.90–1.02; p=0.199).ConclusionLong-term aspirin use is associated with reduced 5-year all-cause mortality in healthy adults, especially those aged <60 years.     

Longitudinal association of sleep-disordered breathing and nondipping of nocturnal blood pressure in the Wisconsin Sleep Cohort Study

STUDY OBJECTIVES: The association of sleep-disordered breathing (SDB) and blunting of normal nocturnal lowering of blood pressure (BP) (nondipping) has only been examined cross-sectionally. The purpose of this study is to investigate whether SDB is prospectively associated with nondipping. METHODS: The longitudinal association between SDB and incident nondipping was examined in a subsample of 328 adults enrolled in the Wisconsin Sleep Cohort Study who completed 2 or more 24-hour ambulatory BP studies over an average of 7.2 years of follow-up. SDB identified by baseline in-laboratory polysomnography was defined by apnea-hypopnea index (AHI) categories. Systolic and diastolic nondipping was defined by systolic and diastolic sleep-wake BP ratios > 0.9. All models were adjusted for age, sex, body mass index at baseline and follow-up, smoking, alcohol consumption, hypertension, sleep time, length of follow-up time, and antihypertensive medication use. RESULTS: There was a dose-response increased odds of developing systolic nondipping in participants with SDB. The adjusted odds ratios (95% confidence interval) of incident systolic nondipping for baseline AHI 5 to < 15 and AHI > or = 15, versus AHI < 5, were 3.1 (1.3-7.7) and 4.4 (1.2-16.3), respectively (P trend = 0.006). The adjusted odds ratios (95% confidence interval) of incident diastolic nondipping for corresponding SDB categories were not statistically significant: 2.0 (0.8-5.6) and 1.3 (0.2-7.1). CONCLUSIONS: Our longitudinal findings of a dose-response increase in development of systolic nondipping of BP with severity of SDB at baseline in a population-based sample provide evidence consistent with a causal link. Nocturnal systolic nondipping may be a mechanism by which SDB contributes to increased cardiovascular disease.     

Treatment of Childhood Sleep Disorders: Generalization Across Disorders and Effects on Family Members

Investigated the treatment of bedtime problems and its generalizationto night wakings. Six children (M age = 35 months) and theirparents participated in this study. A multiple-baseline designacross subjects was employed and found that treatment institutedat bedtime was successful in relieving both bedtime disturbancesand night wakings. Furthermore, significant positive changesin parental Sleep and family satisfaction occurred followingamelioration of the children's sleep problems. Data supportrecent work suggesting that chronic sleep problems in childrenare amenable to behavioral interventions. In addition, thismethod appears to be more cost-effective and less stressfulfor parents to implement than behavioral interventions thatdirectly target night wakings.     

Effect of Varying the Time of Sleep on Sleep, Vigilance, and Self-Rated Activation

The effect of varying the time of sleep (2100-0500, 2400-0800, and 0300-1100 hrs) on the sleep, vigilance, and self-rated activation of 9 normal subjects was assessed. REM% increased, and Stage 2% decreased, with progressively later bedtimes. An hour by hour analysis showed, however, that the increase in REM sleep was confined to the second 3 hrs of sleep. Vigilance and self-rated activation, assessed 30 min after waking, at midday and in the early evening, did not differ between conditions but varied reliably with time of day. It is concluded that shifts away from the conventional 2400-0800 sleep period do not impair performance. Rather, the changes in sleep (between conditions) and performance (within conditions) are, in the main, consistent with the known circadian rhythms of REM sleep propensity and performance efficiency.