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Recently, several institutions, including the American Academy of Sleep Medicine, the Sleep Research Society, and the National Sleep Foundation, have made consensus recommendations concerning appropriate sleep duration for adults. Although numerous studies conducted in Western populations have provided evidence of the harmful effects of short or long sleep duration on mental health, it is still unclear whether these consensus recommendations are appropriate in Korean culture.
Data from 1,892 subjects with no history of medical or psychiatric diagnoses were selected from the Korea National Health and Nutrition Examination Survey of 2014. Subjects were divided into seven groups based on their sleep duration (≤4, 5, 6, 7, 8, 9, and ≥10 hours). Depressive symptoms were measured using the Patient Health Questionnaire-9 and perceived stress severity was evaluated using a Likert-type scale. Group differences in depressive symptoms and severity of stress were analyzed using an analysis of covariance.
Depressive symptoms in subjects with sleep duration of ≤4 hours (5.7±5.9) or 5 hours (3.4±3.9) were higher than in subjects with a sleep duration of 7 (2.2±2.9) or 8 hours (2.2±2.9) (corrected P<0.05). Furthermore, subjects with a short sleep duration (5 hours or below) had greater perceived stress severity than subjects with a sleep duration of 7 or 8 hours (corrected P<0.05).
Our results suggest that maintaining an appropriate sleep duration as found in the recent consensus recommendation is important for mental health, even in healthy subjects without any medical or psychiatric illnesses, in Korea.
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Youth suicide is increasingly being recognized as a major social problem in South Korea. In this study, we aimed to explore the effects of parental support on the relationship between life stress and suicidal ideation among middle-school students.
This study analyzed data from a cross-sectional study on mental health conducted by the South Korea National Youth Policy Institute between May and July of 2013. Questionnaire responses from 3,007 middle-school students regarding stress factors, thoughts of suicide during the past year, and parental support were analyzed in terms of 3 subscale elements: emotional, academic, and financial support.
Among the participants, 234 male students (7.8%) and 476 female students (15.8%) reported experiencing suicidal ideation in the past year. Life stress significantly influenced suicidal ideation (P<0.001), and parental support and all of the subscale elements had a significant influence on decreasing suicidal ideation. As shown in model 1, life stress increased suicidal ideation (adjusted odds ratio [aOR], 1.318; P<0.001), and, in model 2, the effect of life stress on suicidal ideation decreased with parental support (aOR, 1.238; P<0.001).
Parental support was independently related to a decrease in suicidal ideation, and life stress was independently related to an increase in suicidal ideation. Parental support buffered the relationship between life stress and suicidal ideation.
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The prevalence of hearing impairment is increasing and an association between hearing impairment and mental health has been reported. Our study aimed to determine the association between hearing impairment and mental health in Korea.
This was a cross-sectional study of data from the Korean National Health and Nutrition Examination Survey 2010–2013, with a sample size of 18,563 individuals (6,395 with hearing impairment and 12,168 without hearing impairment), aged ≥20 years.
The female group with hearing impairment tended to have a higher rate of stress (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.11 to 1.56). The association between hearing impairment and depressive symptoms was higher in elderly males (OR, 1.60; 95% CI, 1.10 to 2.32), while the association of hearing impairment with suicide ideation was higher in elderly females (OR, 1.32; 95% CI, 1.00 to 1.75).
Elderly individuals with hearing impairment are easily susceptible to poor mental health status. Early targeted intervention to address mental health problems is recommended for people with hearing impairment.
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Medical students are usually under more stress than that experienced by non-medical students. Stress testing tools for Korean medical students have not been sufficiently studied. Thus, we adapted and modified the East Asian Student Stress Inventory (EASSI), a stress testing tool for Korean students studying abroad, and verified its usefulness as a stress test in Korean university students. We also compared and analyzed stress levels between medical and non-medical students.
A questionnaire survey was conducted on medical and non-medical students of a national university, and the responses of 224 students were analyzed for this study. Factor analysis and reliability testing were performed based on data collected for 25 adapted EASSI questions and those on the Korean version of the Global Assessment of Recent Stress Scale (GARSS). A correlation analysis was performed between the 13 modified EASSI questions and the GARSS, and validity of the modified EASSI was verified by directly comparing stress levels between the two student groups.
The 13 questions adapted for the EASSI were called the modified EASSI and classified into four factors through a factor analysis and reliability testing. The Pearson's correlation analysis revealed a significant correlation between the modified EASSI and the Korean version of the GARSS, suggesting a complementary strategy of using both tests.
The validity and reliability of the EASSI were verified. The modified Korean EASSI could be a useful stress test for Korean medical students. Our results show that medical students were under more stress than that of non-medical students. Thus, these results could be helpful for managing stress in medical students.
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Although several risk factors associated with reduced age at natural menopause (ANM) have been investigated, the results are inconsistent. Excessive stress, which leads to elevation of stress hormones, can also negatively affect reproductive ability, including by accelerating menopause. However, a direct association between stress level and ANM has not yet been demonstrated. Therefore, the object of this study was to investigate the association between stress level and ANM in Korean women.
Study participants were Korean women between 40 and 70 years old who were in natural menopause during the 5th Korean National Health and Nutrition Examination Survey (n=3,176). The level of stress in daily life was estimated based on data from the mental health topics of the survey. We used the t-test and one-way analysis of variance to analyze the correlation between stress level and ANM. Regression (β) coefficients calculated by multiple regression analysis were used to estimate various factors affecting ANM.
Women who experienced a high level of stress in daily life had a lower mean ANM than women with a low stress level (50.17±3.7 and 50.58±3.5 years, respectively), with a statistically significant correlation (P<0.05). This correlation was still observed after adjusting for age, body mass index, menstrual regularity, and personal income (P<0.05 for variables).
In Korean women between 40 and 70 years of age who are in natural menopause, there is a statistically significant correlation between stress level and ANM. In particular, women who experience a high level of stress in daily life have reduced ANM.
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Given emerging evidence of the association between stress and disease, practitioners need a tool for measuring stress. Several instruments exist to measure perceived stress; however, none of them are applicable for population surveys because stress conceptualization can differ by population. The aim of this study was to develop and validate the Perceived Stress Inventory (PSI) and its short version for use in population surveys and clinical practice in Korea.
From a pool of perceived stress items collected from three widely used instruments, 20 items were selected for the new measurement tool. Nine of these items were selected for the short version. We evaluated the validity of the items using exploratory factor analysis of the preliminary data. To evaluate the convergent validity of the PSI, 387 healthy people were recruited and stratified on the basis of age and sex. Confirmatory analyses and examination of structural stability were also carried out. To evaluate discriminatory validity, the PSI score of a group with depressive symptoms was compared with that of a healthy group. A similar comparison was also done for persons with anxious mood.
Exploratory factor analysis supported a three-factor construct (tension, depression, and anger) for the PSI. Reliability values were satisfactory, ranging from 0.67 to 0.87. Convergent validity was confirmed through correlation with the Perceived Stress Scale, Center for Epidemiologic Studies Depression Scale, and State-Trait Anxiety Inventory. People with depressive or anxious mood had higher scores than the healthy group on the total PSI, all three dimensions, and the short version.
The long and short versions of the PSI are valid and reliable tools for measuring perceived stress. These instruments offer benefits for stress research using population-based surveys.
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The harmful effects of sedative medications and substances in conjunction with limited research regarding predictive psychological constructs of drug abuse necessitate further investigation of associated factors. Therefore, the present study aimed to elucidate the roles of perceived stress, alexithymia, and psychological health as predictors of sedative abuse in medical students.
In this cross-sectional study, 548 students at Kermanshah University of Medical Sciences, Iran, were selected using stratified random sampling. The data were obtained using the Perceived Stress Scale, an alexithymia scale (Farsi version of the Toronto Alexithymia Scale-20), and a General Health Questionnaire to assess psychological health. Data were analyzed using discriminant analyses.
The results demonstrated that the user and non-user of sedative substances groups had significantly different predictive variables (except for social function disorder) (P>0.05). Physical complaints, alexithymia, and perceived stress, which had standard coefficients of 0.80, 0.60, and -0.27, respectively, predicted sedative drug use.
The results of the present study indicate that perceived stress, alexithymia, physical complaints, anxiety, and depression are associated with sedative drug abuse.
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The relationship between economics and health has been of great interest throughout the years. The accumulated data is not sufficient enough to carry out long-term studies from the viewpoint of morbidity, although Korea National Health and Nutrition Examination Survey (KNHANES) was carried out yearly since 1998 in Korea. Thus, we investigated the effect of the 2008 global economic crisis on health indicators of Korea.
Health indicators were selected by paired t-test based on 2007 and 2009 KNHANES data. Age, gender, body mass index (BMI), smoking, drinking, exercise, education, income, working status, and stress were used as confounding factors, which were analyzed with logistic and probit analyses. Validation was done by comparing gross domestic product (GDP) growth rates and probit analyses results of 2007-2012 KNHANES data.
Among several health indicators, the prevalence of hypertension and stress perception was higher after the economic crisis. Factors related with higher hypertension prevalence include older age, male gender, higher BMI, no current tobacco use, recent drinking, lower education levels, and stress perception. Factors related with more stress perception were younger age, female gender, current smoking, lower education levels, and lower income. GDP growth rates, a macroeconomic indicator, are inversely associated with hypertension prevalence with a one-year lag, and also inversely associated with stress perception without time lag.
The economic crisis increased the prevalence of hypertension and stress perception. In the case of GDP growth rate change, hypertension was an inversely lagging indicator and stress perception was an inversely-related coincident indicator.
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In this Study, we investigated the effects of lifestyle and metabolic syndrome on free oxygen radical levels in men and women in Korea.
A total of 254 adults were included in this study from February 2011 to June 2012 at a health promotion center. Information of the lifestyles and presence of metabolic syndrome factors was obtained. Biochemical markers were measured and free oxygen radicals test (FORT) was performed on the blood.
Of the 254 subjects, 86 (33.9%) had metabolic syndrome, and 187 (73.6%) were men. Between the subjects with and without metabolic syndrome, there was a significant increase in alanine aminotransferase and serum FORT values in the subjects with metabolic syndrome. Multiple linear regression analysis showed that high-sensitivity C-reactive protein (hs-CRP) (P = 0.004), metabolic syndrome (P = 0.037), and female gender (P = 0.030) were independent predictors of serum FORT values. The subjects with high fasting blood sugar level or low high density lipoprotein cholesterol levels showed high serum FORT values.
High hs-CRP, the presence of metabolic syndrome, and female gender were associated with the high oxidative stress. High oxidative stress was associated with the presence of metabolic syndrome.
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The purpose of this study was to examine the levels of occupational stress and physical symptoms among family medicine residents and investigate the effect of subscales of occupational stress on physical symptoms.
A self-administered questionnaire survey of 1,152 family medicine residents was carried out via e-mail from April 2010 to July 2010. The response rate was 13.1% and the R (ver. 2.9.1) was used for the analysis of completed data obtained from 150 subjects. The questionnaire included demographic factors, resident training related factors, 24-items of the Korean Occupational Stress Scales and Korean Versions of the Wahler Physical Symptom Inventory.
The total score of occupational stress of family medicine residents was relatively low compared to that of average workers. The scores of 'high job demand', 'inadequate social support', 'organizational injustice', and 'discomfort in occupational climate' were within the top 50%. Parameters associated with higher occupational stress included level of training, on-duty time, daily patient load, critical patient assigned, total working days, night duty day, sleep duration, and sleep quality. The six subscales of occupational stress, except for 'Job insecurity', had a significant positive correlation with physical symptom scores after adjustment had been made for potential confounders (total score, r = 0.325 and P < 0.001; high job demand, r = 0.439 and P < 0.001).
After the adjustment had been made for potential confounders, the total score of occupational stress and six subscales in family medicine residents showed a significant positive correlation with physical symptom scores.
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Cigarette smoking causes cardiovascular disease and activates markers of endothelial dysfunction or injury. We investigated the nailfold capillary blood velocity (NCV) in cigarette smokers compared to non-smokers.
Forty-eight men (eighteen non-smokers and thirty smokers) were recruited. We measured NCV using nailfold capillary microscopy and exhaled carbon monoxide (ECO) concentration three times (before smoking; NCV0min and ECO0min, and after smoking; NCV5min, ECO5min, NCV30min, and ECO30min), in a condition of fasting in the case of smokers. In non-smokers, the same measurements were taken without smoking. Additionally, personal cigarette smoking and alcohol drinking history were acquired by a self-administrated questionnaire.
Mean age, waist circumference, ECO0min, ECO5min, and ECO30min was higher and NCV5min and NCV30min were significantly lower in smokers compared to non-smokers. Total smoking years were negatively correlated with NCV5min. Average pack of the daily smoking, total pack-years, as well as total smoking years were also negatively correlated with NCV30min by regression analysis. After adjustment of significantly different variables, NCV30min was significantly lower in smokers. In the subgroup analysis, the interleukin-6 level was significantly increased in subjects with a long period of cigarette smoking compared with non-smokers.
Reduction of NCV in smokers is associated with personal smoking history, not with body composition or certain oxidative stress markers.
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Physical and mental health of workers is threatened due to various events and chronic occupational stress. This study was conducted to investigate the relationship between occupational stress and gastric disease in male workers of the shipbuilding industry.
Occupational stress measured among a total of 498 workers of a shipbuilding firm who visited the hospital for health examination using the Korean Occupational Stress Scale (KOSS)-short form, and the relationship between sociodemographic factors, health-related behaviors, occupational stress, and gastric disease, and the distribution of occupational stress by sociodemographic factors in the gastric disease group was examined.
There was no significant association between gastric disease and total occupational stress score and its seven sub-factors. The analysis showed that risk of gastric disease was significantly higher in the Q1 group in which the stress caused by occupational discomfort among seven sub-factors was lowest than that in the Q4 group (odds ratio, 2.819; 95% confidence interval, 1.151 to 6.908). Analysis only on the gastric disease group showed that the stress score of laborers was higher in the four sub-factors than that of office workers (P < 0.05). Analysis on educational background showed that the scores of the three sub-factors were lower in subjects who's highest level of education was high school (P < 0.01).
This study suggests that it is necessary to improve the culture of Korean collectivism in the workplace and to manage the occupational stress in the low-educated and laborers. It is recommended for future studies to confirm the causal relationship between occupational stress and gastric disease by large scale studies using a KOSS which appropriately reflects workplace culture.
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Ferritin is known to be associated with insulin resistance (IR) and oxidative stress; however, recent studies have shown that there is an association between ferritin and anti-oxidative status. To date, the biphasic response of ferritin to oxidative stress has not been fully evaluated. Thus, we investigated the association between ferritin and IR and anti-oxidative status in obese and non-obese women.
We evaluated the homeostasis model assessment of insulin resistance (HOMA-IR) and total anti-oxidant status (TAS) in a total of 111 healthy women between the ages of 32 and 68 years.
In all of the study subjects, ferritin levels were positively correlated with age (r = 0.38, P < 0.001), body mass index (r = 0.24, P = 0.01), TAS (r = 0.38, P < 0.001) and HOMA-IR (r = 0.20, P = 0.04). In the subgroup analysis, ferritin levels were correlated with age (r = 0.39, P < 0.001) and TAS (r = 0.43, P < 0.001) in the non-obese group and with insulin (r = 0.50, P = 0.02) and HOMA-IR (r = 0.52, P = 0.01) levels in the obese group. On stepwise multiple linear regression analysis, ferritin was found to be independently associated with TAS (B = 177.16, P < 0.0001) in the non-obese group and independently associated with HOMA-IR (B = 30.36, P = 0.01) in the obese group.
Our findings suggest ferritin is associated with IR in obese women and with anti-oxidative status in non-obese women. Further studies are warranted to elucidate the precise role of ferritin in obesity.
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Recently, it has been reported that gamma-glumyltransferase (GGT) is associated with various cardiovascular risk factors including overweight in adults. However, there are few studies on the relationship between GGT and cardiovascular risk factors in children. The aim of this study was to assess the relationship between serum GGT level and overweight in Korean urban children.
This study was a cross-sectional study using data on 390 4th grade students of elementary schools in Gunpo, Korea. Children were divided into 4 groups according to gender-specific quartiles of serum GGT level. Body mass index, waist circumference and body fat percentage were quantified as adiposity indices.
All adiposity indices in children of the highest GGT level quartile were higher than those in children of the lowest quartile. Adjusted odd ratios on overweight of the highest quartile of GGT level compared to the lowest quartile were 14.40 (95% confidence interval [CI], 4.43 to 46.83) in boys and 2.94 (95% CI, 1.06 to 8.16) in girls.
This study shows that high serum GGT level is related with overweight in Korean urban children and this relationship is stronger in boys compared to girls.
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