The relationship between lifestyle regularity and subjective sleep quality

In previous work we have developed a diary instrument-the Social Rhythm Metric (SRM), which allows the assessment of lifestyle regularity-and a questionnaire instrument--the Pittsburgh Sleep Quality Index (PSQI), which allows the assessment of subjective sleep quality. The aim of the present study was to explore the relationship between lifestyle regularity and subjective sleep quality. Lifestyle regularity was assessed by both standard (SRM-17) and shortened (SRM-5) metrics; subjective sleep quality was assessed by the PSQI. We hypothesized that high lifestyle regularity would be conducive to better sleep. Both instruments were given to a sample of 100 healthy subjects who were studied as part of a variety of different experiments spanning a 9-yr time frame. Ages ranged from 19 to 49 yr (mean age: 31.2 yr, s.d.: 7.8 yr); there were 48 women and 52 men. SRM scores were derived from a two-week diary. The hypothesis was confirmed. There was a significant (rho = -0.4, p < 0.001) correlation between SRM (both metrics) and PSQI, indicating that subjects with higher levels of lifestyle regularity reported fewer sleep problems. This relationship was also supported by a categorical analysis, where the proportion of "poor sleepers" was doubled in the "irregular types" group as compared with the "non-irregular types" group. Thus, there appears to be an association between lifestyle regularity and good sleep, though the direction of causality remains to be tested.     

Personality correlates with sleep-wake variables

A mail-in questionnaire study and two confirmatory archival analyses are described. Variables related to personality and measures of sleep timing, sleep quality, and sleep duration were initially assessed by self-report in a sample of 54 working adults (31.5% male, 23-48 yrs). Extraversion and neuroticism were measured by the Eysenck Personality Inventory (EPI), and the level of sub-clinical manic-type symptoms by the Attitude to Life Questionnaire (ATLQ). The quality of sleep was measured by the Pittsburgh Sleep Quality Index (PSQI) and by questions relating to habitual sleep latency and minutes awake after sleep onset from the Sleep Timing Questionnaire (STQ). The duration and timing of sleep was assessed using the STQ separately for work-week nights (Sunday-Thursday) and for weekend nights (Friday and Saturday). Morningness-eveningness was assessed using the Composite Scale of Morningness (CSM). Two confirmatory analyses using separate archival samples (Study A: n=201, 55.7% male, 20-57 yrs; Study B: n=101, 47.5% male, 18-59 yrs) were then used to confirm specific correlations of interest. In both initial and confirmatory studies, increased sub-clinical manic-type symptoms were found to be significantly associated with later bedtimes and wake-times during the work-week and lower (more evening-type) CSM scores, and higher neuroticism was associated with poorer sleep as indicated by higher PSQI scores. In contrast, no significant correlations emerged between any of the personality variables and any of the sleep duration variables. Personality appears to affect certain aspects of the timing and subjective quality of sleep, but not necessarily its duration.     

The Relationship Between Lifestyle Regularity and Subjective Sleep Quality

In previous work we have developed a diary instrument—the Social Rhythm Metric (SRM), which allows the assessment of lifestyle regularity—and a questionnaire instrument—the Pittsburgh Sleep Quality Index (PSQI), which allows the assessment of subjective sleep quality. The aim of the present study was to explore the relationship between lifestyle regularity and subjective sleep quality. Lifestyle regularity was assessed by both standard (SRM-17) and shortened (SRM-5) metrics; subjective sleep quality was assessed by the PSQI. We hypothesized that high lifestyle regularity would be conducive to better sleep. Both instruments were given to a sample of 100 healthy subjects who were studied as part of a variety of different experiments spanning a 9-yr time frame. Ages ranged from 19 to 49 yr (mean age: 31.2 yr, s.d.: 7.8 yr); there were 48 women and 52 men. SRM scores were derived from a two-week diary. The hypothesis was confirmed. There was a significant (rho=?0.4, p<0.001) correlation between SRM (both metrics) and PSQI, indicating that subjects with higher levels of lifestyle regularity reported fewer sleep problems. This relationship was also supported by a categorical analysis, where the proportion of “poor sleepers” was doubled in the “irregular types” group as compared with the “non-irregular types” group. Thus, there appears to be an association between lifestyle regularity and good sleep, though the direction of causality remains to be tested.     

Habitual Sleep Measures are Associated with Overall Body Fat,and not Specifically with Visceral Fat,in Men and Women

Objective

This study aimed to investigate the associations of sleep duration and sleep quality with visceral adipose tissue (VAT) in middle‐aged individuals.

Methods

In this cross‐sectional analysis of baseline measurements of the Netherlands Epidemiology of Obesity (NEO) study, participants underwent anthropometry and completed the Pittsburgh Sleep Quality Index (PSQI) for assessing short sleep duration (as sex‐specific age‐adjusted percentiles) and poor quality (PSQI > 5). VAT was assessed by magnetic resonance imaging in a random subgroup. We performed linear regression analyses to examine associations of short sleep and poor sleep with measures of body fat, adjusted for confounding, including total body fat in models with VAT.

Results

A total of 5,094 participants (52% women; mean age of 56 [SD 6] years), 1,947 of whom had VAT measurements, were analyzed. The difference in VAT between poor sleep (PSQI > 5) and good sleep (PSQI ≤ 5) was 7.2cm² (95% CI: 1.2‐13.8) in women and 16.1cm² (95% CI: 6.2‐26.0) in men. These differences attenuated toward the null after the adjustment for total body fat. Similar patterns of associations were observed for short sleep (lowest 10% compared with median 60%).

Conclusions

Our results suggest that measures of sleep are not specifically associated with a higher amount of VAT.     

汶川地震救援官兵睡眠质量与睡眠自适应的关系研究*

目的:考察汶川地震救援官兵在连续作业状态下睡眠质量及其与睡眠自适应的关系。方法:采用匹兹堡睡眠质量问卷,在地震爆发后约65天左右,对122名救援官兵进行调查;采用匹兹堡睡眠质量问卷和军人睡眠自适应量表,在地震爆发后约102天,对2000名救援官兵进行调查。结果:地震救援官兵在执行任务中睡眠质量差者占72%,结束任务后睡眠质量差者占30%。两组睡眠质量各分量表得分除"催眠药物"因素外均有显著差异;救援官兵的睡眠自适应水平偏低,平均分为2.74,低于理论中点分3分;睡眠质量与睡眠自适应水平之间的关系较为密切,除了与对睡眠的影响因素相关不显著外(相关系数为-.027),与睡眠自适应总体水平及其5个因子的相关在.16-.533之间(P<0.001);睡眠的积极暗示、睡眠的抗干扰力和睡眠的积极态度等3个因子是影响军人睡眠质量总体水平的主要因素。结论:使官兵形成和睡眠有关的积极、正确的信念与态度能够有效改善人们的睡眠质量。     

Subjective sleep quality in premenstrual syndrome

Premenstrual syndrome (PMS) is a cyclical disorder observed in late luteal phase and presenting with behavioral changes that can affect interpersonal relationships and normal daily activity. Sleep disturbances are also common. The aim of this study is to investigate the relationship between PMS and subjective sleep quality with Pitsburg Sleep Quality Index (PSQI) in the Medical Academy students, whom have considerable information about menstruation. PMS was detected with "Premenstrual Syndrome Scale", and PSQI was used to evaluate subjective sleep quality. Chi-square test and Kendall's rank correlation analysis were used in statistical analysis. p values (p < 0.05) were considered as statistical significant. Poor sleep quality was found in the 75.6% of the participants with PMS, and 58.8% of the participants without PMS (p < 0.05). Only component 5 (sleep disorder component) of the PSQI components revealed statistically significant difference (1.7 ± 0.6 in participants with PMS, and 1.5 ± 0.6 without PMS, p < 0.05). There was a positive correlation between total PSQI score and all of its' components, except component 6 (sleeping pill usage component) (p < 0.05). The strongest association was found to be in the component 5 (r = 0.528; p = 0.0001). Results of our study suggested the poor sleep quality due to sleep disorders in women with PMS.     

Psychometric properties and accuracy of the European Portuguese version of the Pittsburgh Sleep Quality Index in clinical and non-clinical samples

To assess the reliability and validity concerning the formal European Portuguese version of the Pittsburgh Sleep Quality Index [PSQI (EP)], its accuracy, and optimal cut-off point. N = 564 volunteers (18–80 years old) recruited in several settings (e.g., university campuses; work place; home; sleep consultations), agreed to complete the PSQI (EP). Subgroups completed additional measures: Insomnia Severity Index (ISI), STOP-Bang, Glasgow Sleep Effort Scale, or responded to a supplementary question about perceived sleep problems. As to internal consistency, Cronbach’s α = 0.75. Principal component analysis revealed a unidimensional structure. Six PSQI (EP) components and total scores were able to discriminate individuals who did versus did not describe having any sleep problem; all PSQI (EP) scores were significantly higher (denoting poorer quality) in participants suffering from a sleep disorder. Most Cohen’s d values showed large magnitude associations. PSQI (EP) and ISI scores were highly correlated, but no significant correlations were found considering STOP-Bang. ROC analysis confirmed an optimal cut-off point > 5 of the PSQI (EP) to detect self-reported poor/good sleepers in non-clinical settings. To discriminate non-clinical from clinical sleep patients, the optimal cutoff was > 7, and AUC = 0.94. The European Portuguese version of the PSQI performs as a reliable, valid, and accurate measure of overall sleep quality in Portuguese participants. Furthermore, results suggest that PSQI (EP) can discriminate poor sleepers in non-clinical settings, in addition to demonstrating high clinical accuracy in signaling potential sleep-disorder cases. In conclusion, the PSQI (EP) is a suitable tool to assess general sleep quality in Portuguese participants, both for clinical or non-clinical applications.

     

The Relationships between Sleep-Wake Cycle and Academic Performance in Medical Students

Survey and laboratory studies suggest that several factors, such as social and academic demands, part-time jobs and irregular school schedules, affect the sleep-wake cycle of college students. In this study, we examined the sleep-wake pattern and the role played by academic schedules and individual characteristics on the sleep-wake cycle and academic performance. The subjects were 36 medical students (male = 21 and female = 15), mean age = 20.7 years, SD = 2.2. All students attended the same school schedule, from Monday to Friday. The volunteers answered a morningness-eveningness questionnaire, the Pittsburgh Sleep Quality Index (PSQI) and kept a sleep-wake diary for two weeks. The relationships between sleep-wake cycle, PSQI, chronotypes and academic performance were analyzed by a multiple regression technique. The results showed that 38.9% of the students had a poor sleep quality according to the PSQI. When the medical students were evening type or moderate evening type the PSQI showed a tendency of poor sleep. The multiple regression analysis showed a correlation between sleep onset, sleep irregularity and sleep length with academic performance. These results suggest that chronotypes influence the quality of the sleep-wake cycle and that irregularity of the sleep-wake cycle, as well as sleep deprivation (average length was 6:52), influence the learning of college students.     

冠心病介入术前患者睡眠质量及相关因素研究

目的:探讨冠心病介入治疗患者术前睡眠质量及其影响因素。方法:采用一般状况调查表、匹兹堡睡眠质量指数(PSQI)量表、焦虑自评量表(SAS)、抑郁自评量表(SDS)、社会支持评定量表(SSRS)对2013年7月至2014年1月在某院心内科接受介入治疗的392例冠心病患者进行问卷调查。结果:发放问卷410份,回收有效问卷392份,有效率为95.6%。392例患者中287例存在睡眠质量问题,总发生率为73.2%,PSQI总分为9.88±3.63。相关因素分析显示年龄、性别、婚姻状况、焦虑、抑郁和社会支持6项是冠心病介入治疗术前患者睡眠质量的预测因素。结论:冠心病介入治疗患者术前睡眠质量较差,并受多种因素影响。     

Sleep Duration and Quality among Different Occupations--China National Study

Objective

To examine the associations between occupation, sleep duration and sleep quality.

Methods

The data for this study was extracted from data collected from the 2008 Chinese Sub-optimal Health Study. Our study sample consisted of 18,316 Chinese subjects aged 18-65. Occupation and other relevant characteristics to sleep were collected. We used the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality and multiple logistic regression models to examine the association of occupation with shortened sleep duration and poor sleep quality.

Results

Farmers had the longest sleep duration (mean=8.22 hours) while the civil servants had the shortest sleep duration (mean=7.85 hours). Farmers also had the best sleep quality (mean score=3.74) while professional workers had the worst sleep quality (mean score=4.87). Compared to civil servants, the OR of shortened sleep duration and poor sleep quality for blue collar workers is 1.39 (95%CI: 1.11-1.73) and 1.28 (95%-CI: 1.15-1.42), respectively, after adjusting for age, sex, marital status, education, area, smoking, drinking, pain, and health status.

Conclusion

sleep duration and quality varied among different Chinese occupation populations. The blue collar workers are more likely to have shortened sleep duration and poor sleep quality.     

Polysomnographic sleep, growth hormone insulin-like growth factor-I axis, leptin, and weight loss

Short sleep appears to be strongly associated with obesity and altered metabolic function, and sleep and growth hormone (GH) secretion seems interlinked. In obesity, both the GH-insulin-like-growth-factor-I (GH-IGF-I) axis and sleep have been reported to be abnormal, however, no studies have investigated sleep in relation to the GH-IGF-I axis and weight loss in obese subjects. In this study polygraphic sleep recordings, 24-h GH release, 24-h leptin levels, free-IGF-I, total-IGF-I, IGF-binding protein-3 (IGFBP-3), acid-labile subunit (ALS), cortisol and insulin sensitivity were determined in six severely obese subjects (BMI: 41+/-1 kg/m(2), 32+/-2 years of age), cross-sectional at baseline, and longitudinal after a dramatically diet-induced weight loss (36+/-7 kg). Ten age- and gender-matched nonobese subjects served as controls. Sleep duration (360+/-17 vs. 448+/-15 min/night; P<0.01), 24-h GH (55+/-9 vs. 344+/-55 mU/l.24 h; P<0.01), free-IGF-I (2.3+/-0.42 vs. 5.7+/-1.2 microg/l; P<0.01), and total-IGF-I (186+/-21 vs. 301+/-18 microg/l; P<0.01) were significantly decreased and 24-h leptin levels were increased (35+/-5 vs. 12+/-3 microg/l; P<0.01) in obese subjects at pre-weight loss compared with nonobese subjects After diet-induced weight loss the differences in GH, free IGF-I, and leptin were no longer present between previously obese and nonobese subjects, whereas a significant difference in sleep duration and total IGF-I levels persisted. Rapid eye movement (REM) sleep, non-REM sleep, IGFBP-3, ALS, and cortisol levels were similar in obese and nonobese subjects. Sleep duration, 24-h GH, and IGF-I levels were decreased and 24-h leptin levels were increased in obese subjects. We conclude that hyposomatotropism and hyperleptinemia in obesity are transient phenomena reversible with weight loss, whereas short sleep seems to persist after weight has been reduced dramatically.     

Time to wake up: No impact of COMT Val158Met gene variation on circadian preferences,arousal regulation and sleep

Dopamine has been implicated in the regulation of sleep–wake states and the circadian rhythm. However, there is no consensus on the impact of two established dopaminergic gene variants: the catechol-O-methyltransferase Val158Met (COMT Val158Met; rs4680) and the dopamine D4 receptor Exon III variable-number-of-tandem-repeat polymorphism (DRD4 VNTR). Pursuing a multi-method approach, we examined their potential effects on circadian preferences, arousal regulation and sleep. Subjects underwent a 7-day actigraphy assessment (SenseWear Pro3), a 20-minute resting EEG (analyzed using VIGALL 2.0) and a body mass index (BMI) assessment. Further, they completed the Morningness–Eveningness Questionnaire (MEQ), the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). The sample comprised 4625 subjects (19–82 years) genotyped for COMT Val158Met, and 689 elderly subjects (64–82 years) genotyped for DRD4 VNTR. The number of subjects varied across phenotypes. Power calculations revealed a minimum required phenotypic variance explained by genotype ranging between 0.5% and 1.5% for COMT Val158Met and between 3.3% and 6.0% for DRD4 VNTR. Analyses did not reveal significant genotype effects on MEQ, ESS, PSQI, BMI, actigraphy and EEG variables. Additionally, we found no compelling evidence in sex- and age-stratified subsamples. Few associations surpassed the threshold of nominal significance (p < .05), providing some indication for a link between DRD4 VNTR and daytime sleepiness. Taken together, in light of the statistical power obtained in the present study, our data particularly suggest no impact of the COMT Val158Met polymorphism on circadian preferences, arousal regulation and sleep. The suggestive link between DRD4 VNTR and daytime sleepiness, on the other hand, might be worth investigation in a sample enriched with younger adults.     

The Relationships between Sleep-Wake Cycle and Academic Performance in Medical Students

Survey and laboratory studies suggest that several factors, such as social and academic demands, part-time jobs and irregular school schedules, affect the sleep-wake cycle of college students. In this study, we examined the sleep-wake pattern and the role played by academic schedules and individual characteristics on the sleep-wake cycle and academic performance. The subjects were 36 medical students (male = 21 and female = 15), mean age = 20.7 years, SD = 2.2. All students attended the same school schedule, from Monday to Friday. The volunteers answered a morningness-eveningness questionnaire, the Pittsburgh Sleep Quality Index (PSQI) and kept a sleep-wake diary for two weeks. The relationships between sleep-wake cycle, PSQI, chronotypes and academic performance were analyzed by a multiple regression technique. The results showed that 38.9% of the students had a poor sleep quality according to the PSQI. When the medical students were evening type or moderate evening type the PSQI showed a tendency of poor sleep. The multiple regression analysis showed a correlation between sleep onset, sleep irregularity and sleep length with academic performance. These results suggest that chronotypes influence the quality of the sleep-wake cycle and that irregularity of the sleep-wake cycle, as well as sleep deprivation (average length was 6:52), influence the learning of college students.     

The association between self‐reported sleep quality and overweight in a Chinese population

Objective:

Sleep quality and obesity are associated with type 2 diabetes, hypertension, and metabolic syndrome. However, there is limited research on the association between sleep quality and obesity, and thus the aim of this study is to investigate this relationship in a Chinese population.

Design and Methods:

Subjects were recruited from the Prevention Health Center of National Cheng Kung University Hospital. Anthropometric data and metabolic parameters were measured. Being overweight or obese was defined according to the recommendations of the Department of Health in Taiwan. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI).

Results:

Of the total 2,803 subjects, 1,059 were classified as normal weight, 1,127 were overweight, and 617 were obese. The global PSQI score were 6.30 ± 2.56, 6.61 ± 2.96, and 7.02 ± 2.95 in subjects who were normal weight, overweight, and obese, respectively (test for trend, P < 0.001). Of the variables tested in the multivariate linear regression model, female gender, being overweight, obesity, sleep duration, and alcohol drinking were significantly associated with global PSQI scores, and in the multivariate logistic regression model, female gender, being overweight, obesity, and sleep duration were independent predictors of poor sleepers after controlling for age, gender, BMI or different weight statuses, sleep duration, alcohol drinking, smoking, habitual exercise, hypertension, newly diagnosed diabetes, total cholesterol, high‐density lipoprotein, triglyceride, estimated glomerular filtration rate, and alanine aminotransferase.

Conclusions:

In conclusion, female gender, being overweight, obesity, and sleep duration were associated with poor sleep quality independent of cardiometabolic risk factors. In clinical practice, subjects who are obese, or even only overweight, should be evaluated for the presence of sleep disturbance.     

睡眠障碍通过下丘脑-垂体-卵巢轴影响女性生育能力的临床研究

摘要 目的：探究睡眠障碍是如何通过下丘脑-垂体-卵巢轴影响女性生育能力的。方法：选择2018年10月至2021年10月于我院妇科内分泌科就诊的育龄期女性80例作为研究对象,根据匹兹堡睡眠质量指数量表（PSQI）评估结果,将所有研究对象按照是否存在睡眠障碍分为睡眠障碍组（n=34例）和非睡眠障碍组（n=46例）。对比分析两组PSQI评分,血清性激素水平,月经周期,生育能力,通过Pearson法分析睡眠障碍与女性生育能力的相关性。结果：（1）睡眠障碍组PSQI总分以及睡眠质量、入睡时间、睡眠时间、睡眠效率、睡眠障碍和日间功能障碍各方面得分均显著高于对照组（P<0.05）;（2）睡眠障碍组卵泡刺激素（FSH）、黄体生成素（LH）较非睡眠障碍组升高,而雌二醇（E₂）水平低于非睡眠障碍组（P<0.05）;（3）两组月经周期比较,睡眠障碍组月经紊乱比例显著高于对照组（P<0.05）;（4）两组生育能力比较,睡眠障碍组生育能力显著低于对照组（P<0.05）。（5）睡眠障碍与FSH和LH均存在负相关性,和E₂存在正相关（P<0.05）。结论：睡眠障碍可减弱下丘脑-垂体-卵巢轴的驱动,导致卵泡刺激素释放缓慢,延长了月经周期,并导致黄体功能下降,增加了未受孕或者再次异位妊娠的发生率。     

The self-morningness/eveningness (Self-ME): An extremely concise and totally subjective assessment of diurnal preference

The assessment of diurnal preference, or the preferred timing of sleep and activity, is generally based on comprehensive questionnaires such as the Horne–Östberg (HÖ). The aim of the present study was to assess the reliability of a subject’s self-classification as extremely morning (Self-MM), more morning than evening (Self-M), more evening than morning (Self-E) or extremely evening (Self-EE) type, based on the last question of the HÖ (Self-ME). A convenience sample of 461 subjects [23.8?±?4.7 years; 322 females] completed a full sleep–wake assessment, including diurnal preference (HÖ), night sleep quality (Pittsburgh Sleep Quality Index, PSQI), daytime sleepiness (Karolinska Sleepiness Scale, KSS), and habitual sleep–wake timing (12?d sleep diaries; n?=?296). Significant differences in HÖ total score were observed between Self-ME classes, with each class being significantly different from neighboring classes (p?<?0.0001). Significant differences in sleep–wake timing (bed time, try to sleep and sleep onset, wake up, and get up time) were observed between Self-ME classes. Such differences were maintained when sleep–wake habits were analysed separately on work and free days, and also in a smaller group of 67 subjects who completed the Self-ME as a stand-alone rather than as part of the original questionnaire. Significant differences were observed in the time-course of subjective sleepiness by Self-ME class in both the large and the small group, with Self-MM and Self-M subjects being significantly more alert in the morning and sleepier in the evening hours compared with their Self-E and Self-EE counterparts. Finally, significant differences were observed in night sleep quality between Self-ME classes, with Self-EE/Self-E subjects sleeping worse than their Self-MM/Self-M counterparts, and averaging just over the abnormality PSQI threshold of 5. In conclusion, young, healthy adults can define their diurnal preference based on a single question (Self-ME) in a way that reflects their sleep–wake timing, their sleepiness levels over the daytime hours, and their night sleep quality. Validation of the Self-ME across the decades and in diseased populations seems worthy.     

Assessment of sleep in subjects with visual impairment: Comparison using subjective and objective methods

The objective of the present study was to verify the agreement between objective and subjective measures of sleep in people with and without visual impairment. Thirty-seven subjects with visual impairment participated in the study (19 blind without light perception and 18 low-vision), as well as 34 subjects with normal vision, with paired age and gender characteristics. For the subjective sleep evaluation, we used the Sleep Quality Index—PSQI and for the objective evaluation we used the ActiGraph GT3X+. Among the three analyzed groups, the blind was the only ones who presented differences between subjective and objective sleep duration (p = 0.021). Furthermore, the concordance between subjective and objective sleep duration (ICC = 0.388; p = 0.108) was not observed in blind subjects, and a greater variability of differences in sleep duration between the two methods was observed by the Bland Altman scatter plot. We concluded that the sleep duration obtained by PSQI did not show agreement for the objective sleep duration in blind subjects without light perception.     

The influence of subjective sleep quality on the association between eveningness and depressive symptoms

Increasing evidence suggests that eveningness is associated with increased risk for depression. Eveningness, however, is also associated with poor sleep quality and the unique role of eveningness in depressive symptomatology remains to be elucidated. The goal of the current study, therefore, was to examine the inter-relationships between eveningness, subjective sleep quality and depressive symptoms in healthy participants free of current or previous depression and sleep disorder. Here, 167 healthy participants (mean age 24.16, 129/38 females/males) completed the reduced Morningness–Eveningness Questionnaire (rMEQ), the Pittsburgh Sleep Quality Index (PSQI) and the Centre for Epidemiological Studies Depression Scale (CES-D). Bootstrap mediation analysis for a simple mediation model including rMEQ, PSQI and CES-D was applied. Eveningness was associated with increased depressive symptoms and mediation analysis showed that this relationship was partly mediated by sleep quality. Our results suggest that indicators of depression observed in evening-type individuals cannot be attributed exclusively to disturbed sleep. We suggest that interventions that target both sleep quality and dysfunctional cognitive styles would be optimal to promote well-being in evening-type individuals.     

Heterogeneity of sleep quality based on the Pittsburgh Sleep Quality Index in a community sample: a latent class analysis

Sleep and Biological Rhythms - This study aims to assess the latent dimensional structure of sleep quality as measured by seven components of the Pittsburgh Sleep Quality Index (PSQI) and evaluate...     

Long-Term Impact of Earthquakes on Sleep Quality

Purpose

We investigated the impact of the 6.3 magnitude 2009 L’Aquila (Italy) earthquake on standardized self-report measures of sleep quality (Pittsburgh Sleep Quality Index, PSQI) and frequency of disruptive nocturnal behaviours (Pittsburgh Sleep Quality Index-Addendum, PSQI-A) two years after the natural disaster.

Methods

Self-reported sleep quality was assessed in 665 L’Aquila citizens exposed to the earthquake compared with a different sample (n = 754) of L''Aquila citizens tested 24 months before the earthquake. In addition, sleep quality and disruptive nocturnal behaviours (DNB) of people exposed to the traumatic experience were compared with people that in the same period lived in different areas ranging between 40 and 115 km from the earthquake epicenter (n = 3574).

Results

The comparison between L’Aquila citizens before and after the earthquake showed a significant deterioration of sleep quality after the exposure to the trauma. In addition, two years after the earthquake L''Aquila citizens showed the highest PSQI scores and the highest incidence of DNB compared to subjects living in the surroundings. Interestingly, above-the-threshold PSQI scores were found in the participants living within 70 km from the epicenter, while trauma-related DNBs were found in people living in a range of 40 km. Multiple regressions confirmed that proximity to the epicenter is predictive of sleep disturbances and DNB, also suggesting a possible mediating effect of depression on PSQI scores.

Conclusions

The psychological effects of an earthquake may be much more pervasive and long-lasting of its building destruction, lasting for years and involving a much larger population. A reduced sleep quality and an increased frequency of DNB after two years may be a risk factor for the development of depression and posttraumatic stress disorder.