• Journal of Preventive Medicine and Public Health
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• v.56 no.5
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• pp.458-466
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• 2023

Objectives: The association between long sleep duration and mortality is frequently attributed to the confounding influence of comorbidities. Nevertheless, past efforts to account for comorbidities have yielded inconsistent outcomes. The objective of this study was to evaluate this relationship using a large prospective cohort in Korea. Methods: The study included 114 205 participants from the Health Examinees Study, who were followed for a median of 9.1 years. A composite comorbidity score was developed to summarize the effects of 21 diseases. Using Cox proportional hazards regression, hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause, cancer, and cardiovascular mortality associated with sleep duration were estimated. These estimates were adjusted for socio-demographic factors, lifestyle factors, body mass index, and comorbidity score. Additionally, a stratified analysis by subgroups with and without comorbidities was conducted. Results: Throughout the follow-up period, 2675 deaths were recorded. After all adjustments, an association was observed between a sleep duration of 8 hours or more and all-cause mortality (HR, 1.10; 95% CI, 1.01 to 1.20). However, no such association was detected in the stratified analysis for the subgroups based on comorbidity status. Conclusions: Long sleep duration was found to be associated with all-cause mortality among Koreans, even after adjusting for comorbidities. Additional studies are required to explore the mechanism underlying the association between sleep duration and major causes of mortality.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.1
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• pp.7-10
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• 2022

Hwangryunagyo-tang (HT) is a herbal cocktail to treat insomnia induced by yin deficiency with effulgent fire. In the present study, the onset time and the duration time of sleep were measured 30 minutes after thiopental sodium injection. And c-fos immunohistochemistry was performed to find the activated nerve cells of the ventrolateral preoptic nucleus (VLPO) and tuberomammillary nucleus (TMN) sites in the brain. HT significantly increased the number of activated nerve cells in the sleep-inducing center (VLPO), whereas HT significantly decreased the number of activated nerve cells in the arousal center (TMN). It could be concluded that the HT shortened the onset time and increased the duration time for sleep induced by thiopental sodium. And it was confirmed that the mechanism acted by activating the sleep-inducing center (VLPO) and suppressing the arousal center (TMN) in the brain. The results are considered to be useful as scientific evidence HT can be used clinically for the treatment of insomnia caused by yin deficiency with effulgent fire.

• Human Ecology Research
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• v.57 no.2
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• pp.281-293
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• 2019

This study aimed to examine the effects of socially prescribed perfectionism, sleep duration, and sleep quality on suicidal ideation in Korean high school students and to investigate if sleep duration and quality moderated the relationship between socially prescribed perfectionism and suicidal ideation. The participants of this study were 840 students (544 boys and 296 girls) from six high schools located in Seoul and Gyeonggi-do. The Suicidal Ideation Questionnaire (Reynolds, 1988) was used to measure suicidal ideation. And the socially prescribed perfectionism was assessed by the Multidimensional Perfectionism Scale (Hewitt & Flett, 1991). The students were asked to respond to a question regarding how long they slept a day as well as the Sleep Quality Scale (Yi, 2005). The data were analyzed with descriptive statistics and hierarchical regressions. The moderating effect of sleep duration and quality were investigated using the analysis procedures proposed by Baron and Kenny (1986). The results showed that the level of socially prescribed perfectionism and sleep quality increased the level of suicidal ideation. In addition, sleep quality moderated the relationship between socially prescribed perfectionism and suicidal ideation. The effect of socially prescribed perfectionism on suicidal ideation was greater when sleep quality was poor, compared to when it was good.

• Journal of Korean Biological Nursing Science
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• v.20 no.2
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• pp.103-113
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• 2018

Purpose: This study was performed to assess problems associated with sleep (short and long sleep duration) and to identify risky subgroups with sleep problems among adult cancer survivors. The study is based on the Korea National Health and Nutrition Examination Survey (KNHANES VI and VII) from 2013 to 2016. Methods: The sociodemographic and clinical data of 504 Korean cancer survivors aged 20-64 years was extracted from the KNHANES VI and VII database. Descriptive statistics for complex samples was used, and decision-tree analyses were performed using the SPSS WIN 24.0 program. Results: The mean age for survivors was approximately 51 years. The mean sleep duration was 6.97 hours; 36.2% of participants had short (< 7 hours) and 9.9% had long (> 8 hours) sleep duration. From the decision-trees analyses, the characteristics of the adult cancer survivors related to sleep problems were presented with six different pathways. Sleep problems were analyzed according to the survivors' sociodemographic information (age, education, living status, and occupation), clinical characteristics (body mass index, hypercholesterolemia, and anemia) and health-related quality of life (HRQoL). The HRQoL (${\leq}0.5$ or > 0.5 cutoff point) was a significant predictor of the participants' sleep problems because all six pathways were started from this predictor in the model. Conclusion: Health care professionals could use the decision-tree model for screening adult cancer survivors with sleep problems in clinical or community settings. Nursing interventions considering these specific individual characteristics and HRQoL level should be developed to have adequate sleep duration for Korean adult cancer survivors.

• Sleep Medicine and Psychophysiology
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• v.6 no.2
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• pp.116-125
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• 1999

Objectives: The purpose of this study is to investigate the effect of exercise load on sleep structure and stress hormone secretion during sleep. Methods: Five male physical education students were included in this study after giving their written, informed consents in the Research Institute for Sports Science at the University of Hanyang. All subjects have performed for at least 3 years in a regular aerobic exercises such as football, basketball, and running. The subjects were divided into three groups ; NOE(non-exercise), MDE(middle duration exercise), LDE(long duration excercise). MDE group maintained a total of 120 min exercise, and LDE group maintained a total of 300 min exercise by football, basketball or badminton. All subjects were acclimatized to the experimental sleep condition by spending one night under expermental conditions, including the placement of an intravenous catheter. During the subsequent night(24:00-08:00), somnopolygraphic sleep recordings were obtained, and blood for measuring growth hormone, cortisol, testosterone, and $\beta$-endorphin was collected every 120 min throughout the night. Blood samples were obtained from prominent forearm veins of subjects. Then, the samples were immediately placed in ice and centrifuged within 10 min at 3000 rpm at $4^{\circ}C$. Statistical analyses were performed using the SPSS/$PC^+$. Data were analyzed by one-way ANOVA with repeated measures. Results: No significant differences among groups were observed in sleep latency, total sleep time, stage 2 sleep, and slow wave sleep. However, daytime exercise produced significant changes in stage 1 sleep, REM sleep, stage 2 sleep latency, REM sleep latency and sleep efficiency. Stage 1 sleep, stage 2 sleep latency, and REM sleep latency significantly increased in LDE compared to those of NOE and MDE groups. But the amount of REM sleep significantly decreased in LDE. Sleep efficiency of MDE was higher than those of NOE and LDE. The blood concentrations of growth hormone, testosterone, and cortisol during night sleep were significantly lower in LDE than in NOE. $\beta$-endorphin concentrations in blood during night sleep were not different among groups. Conclusion: The daytime exercise load was significantly related to sleep structure and stress hormone secretion during night sleep. Long duration exercise showed a harmful effect on sleep structure and hormone secretion. However, middle duration exercise had a beneficial effect on sleep structure and hormone secretion during sleep.

• Sleep Medicine and Psychophysiology
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• v.24 no.2
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• pp.86-96
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• 2017

Objectives: This study aimed to analyze causality among sleep apnea, depression and cognitive function in patients with obstructive sleep apnea. Methods: We reviewed the medical records of 105 patients with sleep apnea and snoring who underwent overnight polysomnography (PSG). We analyzed various biological data, sleep variables (sleep duration and percentage) and respiratory variables [arousal index (AI), periodic leg movement index (PLM index), snoring Index (SI), mean SpO2, minimum SpO2, apnea-hypopnea index (AHI), and respiratory disturbance index (RDI)]. We also analyzed various data by sleep, cognition, and mood related scales: Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), snoring index by scale (SIS), Montreal Cognitive Assessment-Korean (Moca-K), Mini-mental State Examination-Korean (MMSE-K), clinical dementia rating (CDR), and Beck Depression Inventory (BDI). We analyzed causation among sleep, and respiratory, mood, and cognition related scales in obstructive sleep apnea patients. We analyzed the mediating effects of depression on sleep apnea patient cognition. Results: As Duration N1 increased and Total sleep time (TST) decreased, MOCA-K showed negative causality (p < 0.01). As BDI and supine RDI increased, causality was negatively related to MOCA-K (p < 0.01). As PSQI (p < 0.001) and SIS (p < 0.01) increased and as MMSE-K (p < 0.01) decreased, causality was positively related to BDI. BDI was found to mediate the effect of age on MOCA-K in patients with obstructive sleep apnea. Conclusion: Duration N1, total sleep time, BDI, and supine RDI were associated with cognitive function in obstructive sleep apnea patients. Depression measured by BDI partially mediated cognitive decline in obstructive sleep apnea patients.

• Clinical and Experimental Pediatrics
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• v.64 no.3
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• pp.111-116
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• 2021

In infants and young children, bedtime problems and night waking are common and the main presentations of insomnia. Poor sleep may critically impact the daytime functioning and mood of the child and their caregivers. A comprehensive sleep history, a sleep diary/log, and the BEARS (Bedtime problems, Excessive daytime sleepiness, Awakenings during the night, Regularity and duration of sleep, and Sleep-disordered breathing) sleep screen are useful for diagnosing sleep problems in young children. Behavioral therapies for this type of insomnia include extinction, bedtime fading with positive routines, and scheduled awakening. Previous studies of behavioral interventions for young children showed significant improvements in sleep-onset latency, night waking frequency, and night waking duration. Parent education about their child's sleep, bedtime routines, and sleep hygiene is essential for treatment.

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.219-230
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• 2022

This study aims to evaluate the effect of sleep duration on obesity in Korean adult using data from the 8th Korea National Health And Nutrition Examination Survey in 2019. The study subjects were 5,213, and we performed frequency analysis, descriptive statistics, and multivariate regression analysis using the SPSS Win 27.0 program. The average sleep duration of the subjects was 6.8 hours per day, and the average body mass index (BMI) was 23.9 kg/m². As a result of bivariate analysis of factors affecting sleep duration, age, education level, stress, depression, diabetes, hypertension, and arthritis were significantly associated with sleep duration. The body mass index (BMI) of the group with less than 6 hours of sleep duration was 24.4, which was higher than that of other groups, and there was a significant negative correlation between sleep duration and BMI (B=-0.247; 95% CI=-0.334~ -0.160). In conclusion, in order to prevent obesity in adults, various efforts from the country and local communities are needed to increase sleep duration.

• Journal of Korean Home Economics Education Association
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• v.30 no.4
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• pp.1-14
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• 2018

The purpose of this study was to examine the relevance of mental health and nutritional intake according to the sleep duration of Korean adolescents. This study was based on data from the 2007-2016 Korea National Health and Nutrition Examination Survey(KNHNES), including 5,489 total subjects (2,795 middle school students, 2,694 high school students). The association between sleep duration and mental health was analyzed using a logistic regression analysis, and the link between sleep duration and nutritional intake was analyzed via a generalized linear model. An analysis of sleep duration showed that middle school students had a higher average sleep duration than high school students (P<0.0001). An analysis of the relationship between sleep duration and mental health showed that middle school students had lower rates of stress perception (P<0.0001) and suicidal ideation (P=0.0005) as their sleep duration increased. High school students had 53% less suicidal ideation in the group getting 6-7 hours compared to the group getting less than 6 hours, and 37% less suicidal ideation than the group getting 7-8 hours. The link between sleep duration and stress perception was statistically significant among both middle and high school students (P for interaction=0.02). An analysis of the daily intake of major nutrients according to sleep hours found high intake of vitamin C in groups where high school students slept more than nine hours (P=0.003). The state of nutritional intake according to higher sleep duration showed statistically significant differences between higher intake of phosphorus, riboflavin, niacin, and vitamin C in Nutrient Adequacy Ratio for high school students. In conclusion, adolescents' sleep duration is associated with stress perception, suicidal ideation and nutritional intake. Therefore, this study emphasizes the mental importance of adolescent sleep and can be used as a basis for nutrition education.

• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.731-742
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• 2019

Objectives: To analyze the association between sleep duration and the number of remaining teeth in people aged 65 years or older in order to provide basic data for improving sleep quality and developing oral health programs for teeth maintenance. Methods: The raw data for the analysis were obtained from the sixth Korean National Health and Nutrition Examination Survey (KNHANES) dataset, conducted between 2013 and 2015. The 4,340 subjects included in the study underwent oral examinations and then proceeded to answer related questions. The collected data were analyzed using SPSS (ver 23.0) program via composite samples, with the calculations for mean, standard deviation, chi-square test, and logistic return analysis being performed. Results: An analysis of the effect of sleep duration on the number of remaining teeth among people aged >65 years old showed that if the confounding variables were not corrected for, the risk of having less than 9 hours of sleep was 1.40 times higher (95% CI: 1.06-1.86). However, this was not statistically significant in models that corrected for gender, age, and other confounding variables (p>0.05). Conclusions: The association between sleep duration among the elderly with their number of remaining teeth was confirmed. Therefore, measures to improve sleep quality and oral care practices to maintain the remaining teeth in people over 65 years old should be developed.