Association of weekday-to-weekend sleep differences and stress response among a Japanese working population: a cross-sectional study.

OBJECTIVES: To investigate the relationship between differences in weekday-to-weekend sleep habits and stress responses in a working population. METHODS: This cross-sectional study used data from university workers on sleep habits, differences in sleep duration between weekdays and weekends, and each midpoint of the sleep phase on weekdays and weekends. Social jetlag was defined as the difference in the midpoint of the sleep phase between weekdays and weekends. In addition, the Brief Job Stress Questionnaire assessed stress responses and stress-related factors. To examine sleep-related factors affecting stress responses, regression analysis was performed with adjustments for age, sex, and stress-related factors. RESULTS: Analyzed were 2,739 participants. Sleep duration differences obtained by subtracting sleep duration on weekdays from that on weekends, social jetlag, and weekday sleep duration were significantly associated with an increased risk of stress responses in a univariate linear regression model. Adjusting for age, sex, job stressors, and stressor buffering factors did not change this trend. However, when additionally adjusting for all sleep parameters, only sleep duration differences and weekday sleep duration were significantly associated with stress responses (ß 0.67 [95% CI 0.24, 1.10], p = 0.002), (-0.66 [-1.20, -0.13], p = 0.015). CONCLUSIONS: This study provided further evidence that weekday sleep duration and weekday-to-weekend sleep duration differences were independently associated with stress responses even when considering stress-related factors. However, social jetlag was not clearly associated with stress responses. Our findings highlighted the necessity of securing sufficient sleep for stress management and mental health promotion in a working population.

Presenteeism in college students: reliability and validity of the Presenteeism Scale for Students.

OBJECTIVE: Presenteeism is the impaired work performance due to health problems. We aimed to develop a Presenteeism Scale for Students (PSS), and to reveal the existence of presenteeism among students. METHODS: Students (n = 5,701) in 4 national universities in Japan were recruited via the school-based health examination. Moreover, 122 students participated in a 2-week interval test-retest to examine the reliability and criterion-related validity of the PSS. RESULTS: Of the students, 59.2% indicated some health problems. Allergy was most prevalent health problems, affecting 35.7% of the whole students. Students with emotional problems had higher degree of presenteeism than those with the other problems. The Cronbach's α of the work impairment score of the PSS was 0.90. The Spearman's coefficient for the test-retest score was 0.80 (P < 0.001). Regarding criterion-related validity, Spearman's coefficient between the work impairment score of the PSS and summary score of the SF-36 was -0.60 (P < 0.001). CONCLUSIONS: These findings suggest that the PSS can be expected to be useful for assessment of students with presenteeism. Furthermore, we found that the majority of students have some health problems, and proposed that the issue of presenteeism on campus should be addressed.

Anxiety, neuroticism and oxidative stress: cross-sectional study in non-smoking college students.

AIMS: Oxidative stress has gained attention recently in psychiatric medicine and has been reported to be associated with various diseases. However, the psychosocial factors involved in oxidative stress are still not well understood. Thus, the aim of this study was to examine whether anxiety levels and neuroticism were associated with serum oxidative and anti-oxidative status in healthy college students. METHODS: Participants in this cross-sectional study were 54 non-smoking college students. Their serum oxidative status was determined by reactive oxygen metabolites (ROM) and the biological anti-oxidant potential. Anxiety levels and neuroticism were assessed using the State-Trait Anxiety Inventory and the NEO Five-Factor Inventory, respectively. RESULTS: Correlation analysis showed an association of increased ROM concentration with elevated anxiety levels (State, rho = 0.39, P = 0.046; Trait, rho = 0.44, P = 0.024) and the personality trait of neuroticism (rho = 0.47, P = 0.016) in female students. However, the ROM concentration in male students was not associated with the anxiety level or any personality trait. CONCLUSION: Although these findings suggest that neurotic and anxious female students tend to be exposed to oxidative stress, these linkages should be confirmed by multivariate analysis in future research.

Do depressive symptoms correlate with oxidative stress in a sample of healthy college students?

Background and Objectives: Major depression and sub-threshold depressive symptoms are associated with health crisis. Oxidative stress may be a mechanism for major depression. In the present study, we examined the relationship between the degree of depressive symptoms and oxidative status using a reliable and inexpensive method that evaluates endogenous hydroperoxides. Methods: We conducted a cross-sectional study in 54 non-smoking college students and measured serum reactive oxygen metabolites (ROMs) and the biological antioxidant potential (BAP) as an index of oxidative status. Depressive symptoms were assessed by the Beck Depression Inventory (BDI). Results: The concentrations of ROMs did not differ between the lower BDI group (BDI < 14) and the higher BDI group (BDI > 14) (282.7 - 59.84 U.CARR vs 307.7 - 67.51 U.CARR, z = -1.19, P = 0.239). We did find a significant relationship between ROM concentration values and higher BDI scores (rho = 0.30, P = 0.042). BAP levels in the higher BDI group were not significantly greater than those in the lower BDI group (z = -0.108, P = 0.287). There was no significant correlation between BAP and depressive symptoms (rho = 0.22, P = 0.140). Moreover, we conducted a multiple regression analysis to control for gender difference and difference in sleep perception of the previous night between the two BDI groups. However, depressive symptoms were not significantly predicted by ROM concentrations (b = 0.28, P = 0.076). Conclusions: While results of the present study demonstrated a slight correlation between depressive symptoms and oxidative stress, this linkage could not be confirmed after controlling for significant confounding factors. This result should be verified in a larger sample (AU)

Clinical significance of pulse rate rise during sleep as a screening marker for the assessment of sleep fragmentation in sleep-disordered breathing.

OBJECTIVE: To assess the clinical utility of the frequencies of transient increases of pulse rate, non-invasively measured with a pulseoximeter, as an indirect indication of the degree of cortical arousal, measured conventionally on an electroencephalogram (EEG), in obstructive sleep apnea-hypopnea syndrome (OSAHS) patients. PATIENTS AND METHODS: Thirty-three consecutive patients referred with suspected OSAHS were studied. Polysomnography (PSG) with determination of esophageal pressure (Pes) and pulseoximetry was monitored to identify breathing-related EEG arousal (B-Ar) associated with apnea, hypopnea or respiratory effort and the frequencies of pulse rate increases. We also assessed the association of B-ArI (defined as the number of B-Ar per hour) with the pulse rate rise index (PRRI)-X(X=4-10) (defined as the number of pulse rate increases per hour). In addition, the sensitivity and specificity of PRRI for the assessment of a B-ArI cutoff point of 30 were calculated. RESULTS: The sensitivity and specificity of pulseoximetry for different thresholds of PRRI-X(X=4-10) demonstrated that the greatest diagnostic accuracy for detecting frequent arousal (B-ArI > or =30) occurs at a cutoff point of 40 PRRI-6 with a sensitivity of 0.88 and specificity of 0.86. This point shows a significant area under the curve of 0.84. In addition, a statistically significant correlation between PRRI-6 and B-ArI (r=0.68, P<0.0001) was observed. CONCLUSIONS: The transient increases in pulse rate measured by pulseoximetry during sleep may be a useful clinical marker for predicting the degree of arousal in OSAHS patients, and may, in addition, prevent cases with frequent respiratory effort related arousals from being overlooked. However, further studies are required to improve the confidence level of the PRRI and to investigate the causes of overestimation of EEG arousals.

Three components of obstructive sleep apnea/hypopnea syndrome.

The aims of this study were to calculate the apnea-hypopnea index (AHI), which represented as the number of apnea-hypopnea occurrences per hour, the 4% oxygen desaturation index (ODI4) and the breathing-related arousal index (B-ArI) in polysomnographic studies of obstructive sleep apnea/hypopnea syndrome (OSAHS) patients and to investigate whether there was any relationship between each pair of scoring schemes. Thirty-four cases of OSAHS were studied. Total OSAHS patients were subdivided into those with a high AHI (> 25), and those with a low AHI (< 25). The correlation between each pair of scoring schemes for OSAHS with a high AHI showed high value. The correlation between AHI and ODI4 for OSAHS with a low AHI was 0.18 and that between AHI and B-ArI showed a weak correlation of 0.59, while that between ODI4 and B-ArI was only -0.078. Our results mean that oxygen desaturation and arousal occur separately in mild or moderate OSAHS patients, even though they are diagnosed with the same level of OSAHS by means of AHI. Breathing-related arousal without oxygen desaturation often occurs in mild or moderate OSAHS patients. We previously reported that AHI does not accurately reflect the severity of the increase in negativity of esophageal pressure manifested as respiratory efforts. We consider that the comprehension and assessment of OSAHS can be improved by the systematic differentiations among the three components: oxygen desaturation, arousals and respiratory efforts.