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.     

Lifestyle Regularity Measured by The Social Rhythm Metric in Parkinson's Disease

Parkinson's disease (PD) is a chronic progressive motor disorder that may present with a spectrum of symptoms and disease severity. Therapy is frequently associated with motor fluctuations and dyskinesias; therefore, monitoring of motor fluctuations and daily abilities is important for adequate management. The Social Rhythm Metric (SRM) is a diary‐like questionnaire that quantifies the extent to which a person's life is regular vs. irregular on a daily basis with respect to event timing. Lifestyle regularity has been assessed by the SRM in other clinical situations. The aim of this study was to evaluate lifestyle regularity in a population with PD using the SRM and its relationship to clinical and therapeutic factors. Twenty‐eight consecutive patients with PD and 14 control subjects were studied. Severity of motor dysfunction was evaluated with the Unified Parkinson's Disease Rating Scale (UPDRS). Depressive symptoms were assessed with the Montgomery Asberg Depressive Rating Scale (MADRS), sleep quality with the Pittsburgh Sleep Quality Index (PSQI), and subjective daytime sleepiness with the Epworth sleepiness scale. Daily lifestyle regularity was assessed by the SRM for 2 weeks. Patients with PD had lower SRM scores than controls, and those with motor fluctuations had even lower scores (p=0.04). Patients with motor fluctuations showed more clinical disability (p=0.01), a worse quality of sleep (p=0.02), and more depressive symptoms (p=0.02). SRM results were correlated with PSQI values (p=0.016). Our findings show that the regularity of daily activities as measured by the SRM is disorganized in patients with PD and that this irregularity is related to sleep quality.     

Lifestyle regularity measured by the social rhythm metric in Parkinson's disease

Parkinson's disease (PD) is a chronic progressive motor disorder that may present with a spectrum of symptoms and disease severity. Therapy is frequently associated with motor fluctuations and dyskinesias; therefore, monitoring of motor fluctuations and daily abilities is important for adequate management. The Social Rhythm Metric (SRM) is a diary-like questionnaire that quantifies the extent to which a person's life is regular vs. irregular on a daily basis with respect to event timing. Lifestyle regularity has been assessed by the SRM in other clinical situations. The aim of this study was to evaluate lifestyle regularity in a population with PD using the SRM and its relationship to clinical and therapeutic factors. Twenty-eight consecutive patients with PD and 14 control subjects were studied. Severity of motor dysfunction was evaluated with the Unified Parkinson's Disease Rating Scale (UPDRS). Depressive symptoms were assessed with the Montgomery Asberg Depressive Rating Scale (MADRS), sleep quality with the Pittsburgh Sleep Quality Index (PSQI), and subjective daytime sleepiness with the Epworth sleepiness scale. Daily lifestyle regularity was assessed by the SRM for 2 weeks. Patients with PD had lower SRM scores than controls, and those with motor fluctuations had even lower scores (p=0.04). Patients with motor fluctuations showed more clinical disability (p=0.01), a worse quality of sleep (p=0.02), and more depressive symptoms (p=0.02). SRM results were correlated with PSQI values (p=0.016). Our findings show that the regularity of daily activities as measured by the SRM is disorganized in patients with PD and that this irregularity is related to sleep quality.     

Morningness-eveningness and lifestyle regularity

The relation between morningness (M) - eveningness (E) and lifestyle regularity was studied in a convenience sample of 100 healthy subjects aged between 20 and 59 yrs (47 males and 53 females; mean age 33.6 yrs). Morningness-eveningness was measured by a single administration of the 13-item Composite Scale for Morningness (CSM). Lifestyle regularity was measured by requiring subjects to complete a five-item Social Rhythm Metric diary (SRM-5) each evening for two weeks. Each week of SRM-5 was analyzed separately and the two SRM scores averaged to yield the lifestyle regularity measure for the subject. Subjects were categorized by morningness into top and bottom quartiles of CSM score (denoted M-types and E-types, respectively), with the remaining 50% of subjects denoted as intermediate (I-types). Mean SRM scores significantly differed between the three morningness groups (p <0.001) in the order E-types (SRM = 3.6), then I-types (SRM=4.0), then M-types (SRM=4.9), with higher scores indicating greater daily lifestyle regularity. The effect size of the E-type versus M-type difference was approximately 1.3. The relationship between the CSM and SRM scores was also confirmed using a correlational analysis (rho = 0.428; p < 0.001). This correlational finding was substantially weaker when age was partialed out (r=0.186; p=0.065), although there was still a trend toward a significan relationship. Thus it appears that morning types appear to be more regular in their daily lifestyle than are evening types, suggesting a relationship between these two aspects of human circadian behavior.     

Age-related differences in the lifestyle regularity of seniors experiencing bereavement, care-giving, insomnia, and advancement into old-old age

Compared to younger adults, seniors (> or = 60 yrs) often adopt a highly regular lifestyle, perhaps as an adaptive response to age-related changes in their sleep and circadian rhythms. At baseline, diary measures of lifestyle regularity (SRM-5) were obtained from 104 seniors of three separate groups. Thirty-three subjects were challenged by spousal bereavement or the need to care for a spouse at home with dementia (Challenged); 33 were suffering from formally diagnosed (DSM-IV) insomnia (Insomnia); and 38 were healthy, well-functioning older seniors in the second half of their eighth decade of life or later (Healthy Older). The objective of this study was to determine whether lifestyle regularity increased as a function of age within each of these three senior groups. Overall, age was significantly correlated with SRM-5 (r=0.41, p<0.001), with the SRM score increasing by 0.67 units/decade. The same was true for the Challenged and Insomnia groups, which also showed a significant correlation between SRM and age (Challenged: r=0.48, p<0.01; Insomnia: r=0.36, p<0.05), though with a slightly faster rate of SRM increase in the Challenged (0.95 units/decade) than Insomnia (0.55 units/decade) group. Perhaps there was no correlation between age and SRM (r=0.07, n.s.) in the Healthy Older group due to the small age range, although this group did have a higher overall SRM score than the other two groups (p<0.01). The study thus confirmed that the previously observed increase in lifestyle regularity over the adult lifespan persists into later life. This may represent an adaptive behavioral response that might be used in future therapeutic approaches.     

Circadian Preference and Sleep-Wake Regularity: Associations With Self-Report Sleep Parameters in Daytime-Working Adults

The aim of this study was to explore how interindividual differences in circadian type (morningness) and sleep timing regularity might be related to subjective sleep quality and quantity. Self-report circadian phase preference, sleep timing, sleep quality, and sleep duration were assessed in a sample of 62 day-working adults (33.9% male, age 23–48 yrs). The Pittsburgh Sleep Quality Index (PSQI) measured subjective sleep quality and the Sleep Timing Questionnaire (STQ) assessed habitual sleep latency and minutes awake after sleep onset. The duration, timing, and stability of sleep were 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). Daytime sleepiness was measured using the Epworth Sleepiness Scale (ESS). A morning-type orientation was associated with longer weekly sleep duration, better subjective sleep quality, and shorter sleep-onset latency. Stable weekday rise-time correlated with better self-reported sleep quality and shorter sleep-onset latency. A more regular weekend bedtime was associated with a shorter sleep latency. A more stable weekend rise-time was related to longer weekday sleep duration and lower daytime sleepiness. Increased overall regularity in rise-time was associated with better subjective sleep quality, shorter sleep-onset latency, and higher weekday sleep efficiency. Finally, a morning orientation was related to increased regularity in both bedtimes and rise-times. In conclusion, in daytime workers, a morning-type orientation and more stable sleep timing are associated with better subjective sleep quality. (Author correspondence: asoehner@berkeley.edu)     

Sleep and circadian rhythms in spousally bereaved seniors

A laboratory study of sleep and circadian rhythms was undertaken in 28 spousally bereaved seniors (> or =60 yrs) at least four months after the loss event. Measures taken included two nights of polysomnography (second night used), approximately 36 h of continuous core body temperature monitoring, and four assessments of mood and alertness throughout a day. Preceding the laboratory study, two-week diaries were completed, allowing the assessment of lifestyle regularity using the 17-item Social Rhythm Metric (SRM) and the timing of sleep using the Pittsburgh Sleep Diary (PghSD). Also completed were questionnaires assessing level of grief (Texas Revised Inventory of Grief [TRIG] and Index of Complicated Grief [ICG]), subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), morningness-eveningness (Composite Scale of Morningness [CSM]), and clinical interview yielding a Hamilton Depression Rating Scale (HDRS) score. Grief was still present, as indicated by an average TRIG score of about 60. On average, the bereaved seniors habitually slept between approximately 23:00 and approximately 06:40 h, achieving approximately 6 h of sleep with a sleep efficiency of approximately 80%. They took about 30 min to fall asleep, and had their first REM episode after 75 min. About 20% of their sleep was in Stage REM, and about 3% in Stages 3 or 4 (slow wave sleep). Their mean PSQI score was 6.4. Their circadian temperature rhythms showed the usual classic shape with a trough at approximately 01:00 h, a fairly steep rise through the morning hours, and a more gradual rise to mid-evening, with an amplitude of approximately 0.8 degrees C. In terms of lifestyle regularity, the mean regularity (SRM) score was 3.65 (slightly lower than that usually seen in seniors). Mood and alertness showed time-of-day variation with peak alertness in the late morning and peak mood in the afternoon. Correlations between outcome sleep/circadian variables and level of grief (TRIG score) were calculated; there was a slight trend for higher grief to be associated with less time spent asleep (p=0.07) and reduced alertness at 20:00 h (p=0.05). Depression score was not correlated with TRIG score (p>0.20). When subjects were divided into groups by the nature of their late spouse's death (expected/after a long-term chronic illness [n=18] versus unexpected [n=10]), no differences emerged in any of the variables. In conclusion, when studied at least four months after the loss event, there appears to be some sleep disruption in spousally bereaved seniors. However, this disruption does not appear to be due to bereavement-related disruptions in the circadian system.     

Circadian preference and sleep-wake regularity: associations with self-report sleep parameters in daytime-working adults

The aim of this study was to explore how interindividual differences in circadian type (morningness) and sleep timing regularity might be related to subjective sleep quality and quantity. Self-report circadian phase preference, sleep timing, sleep quality, and sleep duration were assessed in a sample of 62 day-working adults (33.9% male, age 23?48 yrs). The Pittsburgh Sleep Quality Index (PSQI) measured subjective sleep quality and the Sleep Timing Questionnaire (STQ) assessed habitual sleep latency and minutes awake after sleep onset. The duration, timing, and stability of sleep were 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). Daytime sleepiness was measured using the Epworth Sleepiness Scale (ESS). A morning-type orientation was associated with longer weekly sleep duration, better subjective sleep quality, and shorter sleep-onset latency. Stable weekday rise-time correlated with better self-reported sleep quality and shorter sleep-onset latency. A more regular weekend bedtime was associated with a shorter sleep latency. A more stable weekend rise-time was related to longer weekday sleep duration and lower daytime sleepiness. Increased overall regularity in rise-time was associated with better subjective sleep quality, shorter sleep-onset latency, and higher weekday sleep efficiency. Finally, a morning orientation was related to increased regularity in both bedtimes and rise-times. In conclusion, in daytime workers, a morning-type orientation and more stable sleep timing are associated with better subjective sleep quality. (Author correspondence: asoehner@berkeley.edu ).     

Sleep and Circadian Rhythms in Spousally Bereaved Seniors

A laboratory study of sleep and circadian rhythms was undertaken in 28 spousally bereaved seniors (≥60 yrs) at least four months after the loss event. Measures taken included two nights of polysomnography (second night used), ～36 h of continuous core body temperature monitoring, and four assessments of mood and alertness throughout a day. Preceding the laboratory study, two‐week diaries were completed, allowing the assessment of lifestyle regularity using the 17‐item Social Rhythm Metric (SRM) and the timing of sleep using the Pittsburgh Sleep Diary (PghSD). Also completed were questionnaires assessing level of grief (Texas Revised Inventory of Grief [TRIG] and Index of Complicated Grief [ICG]), subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), morningness‐eveningness (Composite Scale of Morningness [CSM]), and clinical interview yielding a Hamilton Depression Rating Scale (HDRS) score. Grief was still present, as indicated by an average TRIG score of about 60. On average, the bereaved seniors habitually slept between ～23:00 and ～06:40 h, achieving ～6 h of sleep with a sleep efficiency of ～80%. They took about 30 min to fall asleep, and had their first REM episode after 75 min. About 20% of their sleep was in Stage REM, and about 3% in Stages 3 or 4 (slow wave sleep). Their mean PSQI score was 6.4. Their circadian temperature rhythms showed the usual classic shape with a trough at ～01:00 h, a fairly steep rise through the morning hours, and a more gradual rise to mid‐evening, with an amplitude of ～0.8°C. In terms of lifestyle regularity, the mean regularity (SRM) score was 3.65 (slightly lower than that usually seen in seniors). Mood and alertness showed time‐of‐day variation with peak alertness in the late morning and peak mood in the afternoon. Correlations between outcome sleep/circadian variables and level of grief (TRIG score) were calculated; there was a slight trend for higher grief to be associated with less time spent asleep (p=0.07) and reduced alertness at 20:00 h (p=0.05). Depression score was not correlated with TRIG score (p>0.20). When subjects were divided into groups by the nature of their late spouse's death (expected/after a long‐term chronic illness [n=18] versus unexpected [n=10]), no differences emerged in any of the variables. In conclusion, when studied at least four months after the loss event, there appears to be some sleep disruption in spousally bereaved seniors. However, this disruption does not appear to be due to bereavement‐related disruptions in the circadian system.     

Age‐Related Differences in the Lifestyle Regularity of Seniors Experiencing Bereavement,Care‐Giving,Insomnia, and Advancement Into Old‐Old Age

Compared to younger adults, seniors (≥60 yrs) often adopt a highly regular lifestyle, perhaps as an adaptive response to age‐related changes in their sleep and circadian rhythms. At baseline, diary measures of lifestyle regularity (SRM‐5) were obtained from 104 seniors of three separate groups. Thirty‐three subjects were challenged by spousal bereavement or the need to care for a spouse at home with dementia (Challenged); 33 were suffering from formally diagnosed (DSM‐IV) insomnia (Insomnia); and 38 were healthy, well‐functioning older seniors in the second half of their eighth decade of life or later (Healthy Older). The objective of this study was to determine whether lifestyle regularity increased as a function of age within each of these three senior groups. Overall, age was significantly correlated with SRM‐5 (r=0.41, p<0.001), with the SRM score increasing by 0.67 units/decade. The same was true for the Challenged and Insomnia groups, which also showed a significant correlation between SRM and age (Challenged: r=0.48, p<0.01; Insomnia: r=0.36, p<0.05), though with a slightly faster rate of SRM increase in the Challenged (0.95 units/decade) than Insomnia (0.55 units/decade) group. Perhaps there was no correlation between age and SRM (r=0.07, n.s.) in the Healthy Older group due to the small age range, although this group did have a higher overall SRM score than the other two groups (p<0.01). The study thus confirmed that the previously observed increase in lifestyle regularity over the adult lifespan persists into later life. This may represent an adaptive behavioral response that might be used in future therapeutic approaches.     

Subjective sleep quality in noncomplaining elderly subjects: results of a follow-up study

The present study aims at investigating subjective sleep quality and its stability in a sample of not complaining elderly subjects (60 to 85 years). Sleep quality was assessed by means of the Pittsburgh Sleep Quality Index (PSQI). At baseline 91 subjects (46 males and 45 females; age: 66.7+/-5.8 years) completed the PSQI. The follow-up study was performed 16 +/-5 months later (response rate: 82.4 %). In the present sample the PSQI revealed that, in spite of the noncomplaining status, sleep is disturbed (PSQI > 5) in 26.0 % of the male and 34.5 % of the female population. Furthermore, sleep quality does not change systematically over the time course of this study. The mean of intraindividual differences is 0.1+/-2.5. This discrepancy between the subjects' claims of no sleep disturbance and their endorsing of PSQI items indicative of disturbed sleep probably reflects an adaptation in the perception of disturbed sleep.     

Depressive Symptoms are the Main Predictor for Subjective Sleep Quality in Patients with Mild Cognitive Impairment—A Controlled Study

Objective

Controlled data on predictors of subjective sleep quality in patients with memory complaints are sparse. To improve the amount of comprehensive data on this topic, we assessed factors associated with subjective sleep quality in patients from our memory clinic and healthy individuals.

Methods

Between February 2012 and August 2014 patients with mild cognitive impairment (MCI) and subjective cognitive decline (SCD) from our memory clinic and healthy controls were recruited. Apart from a detailed neuropsychological assessment, the subjective sleep quality, daytime sleepiness and depressive symptoms were assessed using the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS) and the Beck Depression Inventory (BDI-II).

Results

One hundred fifty eight consecutive patients (132 (84%) MCI patients and 26 (16%) SCD patients) and 75 healthy controls were included in the study. Pairwise comparison of PSQI scores showed that non-amnestic MCI (naMCI) patients (5.4±3.5) had significantly higher PSQI scores than controls (4.3±2.8, p = .003) Pairwise comparison of PSQI subscores showed that naMCI patients (1.1±0.4) had significantly more “sleep disturbances” than controls (0.9±0.5, p=.003). Amnestic MCI (aMCI) (0.8±1.2, p = .006) and naMCI patients (0.7±1.2, p = .002) used “sleep medication” significantly more often than controls (0.1±0.6) Both, aMCI (11.5±8.6, p<.001) and naMCI (11.5±8.6, p<.001) patients showed significantly higher BDI-II scores than healthy controls (6.1±5.3). Linear regression analysis showed that the subjective sleep quality was predicted by depressive symptoms in aMCI (p<.0001) and naMCI (p<.0001) patients as well as controls (p<.0001). This means, that more depressive symptoms worsened subjective sleep quality. In aMCI patients we also found a significant interaction between depressive symptoms and global cognitive function (p = .002)

Discussion

Depressive symptoms were the main predictor of subjective sleep quality in MCI patients and controls, but not in SCD patients. Better global cognitive function ameliorated the negative effect of depressive symptoms on the subjective sleep quality in aMCI patients.     

Construct Validity and Factor Structure of the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale in a Multi-National Study of African,South East Asian and South American College Students

Background

The Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS) are questionnaires used to assess sleep quality and excessive daytime sleepiness in clinical and population-based studies. The present study aimed to evaluate the construct validity and factor structure of the PSQI and ESS questionnaires among young adults in four countries (Chile, Ethiopia, Peru and Thailand).

Methods

A cross-sectional study was conducted among 8,481 undergraduate students. Students were invited to complete a self-administered questionnaire that collected information about lifestyle, demographic, and sleep characteristics. In each country, the construct validity and factorial structures of PSQI and ESS questionnaires were tested through exploratory and confirmatory factor analyses (EFA and CFA).

Results

The largest component-total correlation coefficient for sleep quality as assessed using PSQI was noted in Chile (r = 0.71) while the smallest component-total correlation coefficient was noted for sleep medication use in Peru (r = 0.28). The largest component-total correlation coefficient for excessive daytime sleepiness as assessed using ESS was found for item 1 (sitting/reading) in Chile (r = 0.65) while the lowest item-total correlation was observed for item 6 (sitting and talking to someone) in Thailand (r = 0.35). Using both EFA and CFA a two-factor model was found for PSQI questionnaire in Chile, Ethiopia and Thailand while a three-factor model was found for Peru. For the ESS questionnaire, we noted two factors for all four countries

Conclusion

Overall, we documented cross-cultural comparability of sleep quality and excessive daytime sleepiness measures using the PSQI and ESS questionnaires among Asian, South American and African young adults. Although both the PSQI and ESS were originally developed as single-factor questionnaires, the results of our EFA and CFA revealed the multi- dimensionality of the scales suggesting limited usefulness of the global PSQI and ESS scores to assess sleep quality and excessive daytime sleepiness.     

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 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.     

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.     

Daily activities and sleep quality in college students

There is growing evidence that social rhythms (e.g., daily activities such as getting into or out of bed, eating, and adhering to a work schedule) have important implications for sleep. The present study used a prospective measure of daily activities to assess the relation between sleep and social rhythms. College students (n=243) 18 to 39 yrs of age, completed the Social Rhythm Metric (SRM) each day for 14 d and then completed the Pittsburgh Sleep Quality Index (PSQI). The sample was divided into groups of good or poor sleepers, according to a PSQI cut‐off score of 5 points and was compared on the regularity, frequency, timing, and extent of social engagement during activities. There was a lower frequency and less regularity of social rhythms in poor sleepers relative to good sleepers. Good sleepers engaged more regularly in activities with active social engagement. Earlier rise time, first consumption of a beverage, going outdoors for the first time, and bedtime were associated with better sleep. Greater variability in rise time, consuming a morning beverage, returning home for the last time, and bedtime were associated with more disturbed sleep. The results are consistent with previous findings of reduced regularity in bedtime and rise time schedules in undergraduates, other age groups, and in clinical populations. Results augment the current thought that regulating behavioral zeitgebers may be important in influencing bed and rise times, and suggest that engaging in activities with other people may increase regularity.     

The Association between Self-Reported Sleep Quality and Metabolic Syndrome

Objectives

Short and long sleep duration are associated with metabolic syndrome. However, there is limited research on the association between sleep quality and metabolic syndrome, and thus the aim of this study is to investigate this relationship.

Materials and Methods

The cross-sectional baseline data were collected from the decoded database of the Prevention Health Center of National Cheng Kung University Hospital from 2002 to 2006. The diagnosis of metabolic syndrome was according to the statement of the American Heart Association/National Heart, Lung, and Blood Institute. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). A higher global PSQI score indicates poorer sleep quality, and a global PSQI score greater than five differentiates poor from good sleepers.

Results

Of the 3,435 subjects recruited, 899 (26.2%) had metabolic syndrome. Subjects with metabolic syndrome had higher PSQI and prevalence of poor sleepers than those without metabolic syndrome. The multivariate lineal regression analysis showed that female gender, metabolic syndrome, sleep duration, snoring, alcohol drinking, and habitual exercise were independent predictors of PSQI. When substituting metabolic syndrome with the five components, hyperglycemia and low high-density lipoprotein cholesterol (HDL-C) were positively associated with PSQI. The multivariate logistic regression analyses showed that female gender, metabolic syndrome, sleep duration, and snoring were independently associated with being poor sleepers. Of the five components, only low HDL-C was an independent predictor of being poor sleepers.

Conclusions

Subjects with metabolic syndrome have higher global PSQI scores and a higher risk of being poor sleepers. Of the five components of metabolic syndrome, hyperglycemia and low HDL-C are independently associated with the global PSQI scores, while low HDL-C is an independent predictor of being poor sleepers.     

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.     

Daily activities and sleep quality in college students

There is growing evidence that social rhythms (e.g., daily activities such as getting into or out of bed, eating, and adhering to a work schedule) have important implications for sleep. The present study used a prospective measure of daily activities to assess the relation between sleep and social rhythms. College students (n=243) 18 to 39 yrs of age, completed the Social Rhythm Metric (SRM) each day for 14 d and then completed the Pittsburgh Sleep Quality Index (PSQI). The sample was divided into groups of good or poor sleepers, according to a PSQI cut-off score of 5 points and was compared on the regularity, frequency, timing, and extent of social engagement during activities. There was a lower frequency and less regularity of social rhythms in poor sleepers relative to good sleepers. Good sleepers engaged more regularly in activities with active social engagement. Earlier rise time, first consumption of a beverage, going outdoors for the first time, and bedtime were associated with better sleep. Greater variability in rise time, consuming a morning beverage, returning home for the last time, and bedtime were associated with more disturbed sleep. The results are consistent with previous findings of reduced regularity in bedtime and rise time schedules in undergraduates, other age groups, and in clinical populations. Results augment the current thought that regulating behavioral zeitgebers may be important in influencing bed and rise times, and suggest that engaging in activities with other people may increase regularity.