Optimal Cutoff Points of Anthropometric Parameters to Identify High Coronary Heart Disease Risk in Korean Adults.

Several published studies have reported the need to change the cutoff points of anthropometric indices for obesity. We therefore conducted a cross-sectional study to estimate anthropometric cutoff points predicting high coronary heart disease (CHD) risk in Korean adults. We analyzed the Korean National Health and Nutrition Examination Survey data from 2007 to 2010. A total of 21,399 subjects aged 20 to 79 yr were included in this study (9,204 men and 12,195 women). We calculated the 10-yr Framingham coronary heart disease risk score for all individuals. We then estimated receiver-operating characteristic (ROC) curves for body mass index (BMI), waist circumference, and waist-to-height ratio to predict a 10-yr CHD risk of 20% or more. For sensitivity analysis, we conducted the same analysis for a 10-yr CHD risk of 10% or more. For a CHD risk of 20% or more, the area under the curve of waist-to-height ratio was the highest, followed by waist circumference and BMI. The optimal cutoff points in men and women were 22.7 kg/m(2) and 23.3 kg/m(2) for BMI, 83.2 cm and 79.7 cm for waist circumference, and 0.50 and 0.52 for waist-to-height ratio, respectively. In sensitivity analysis, the results were the same as those reported above except for BMI in women. Our results support the re-classification of anthropometric indices and suggest the clinical use of waist-to-height ratio as a marker for obesity in Korean adults.

Health Behavior and Factors Associated with Depression in North Korean Adolescent Defectors in South Korea: The Korea Youth Risk Behavior Web-Based Survey, 2011-2014.

BACKGROUND: The number of North Korean adolescent defectors entering South Korea has been increasing. The health behavior, including mental health-related behavior, and factors associated with depression in North Korean adolescent defectors residing in South Korea were investigated. METHODS: Data obtained from the Korea Youth Risk Behavior Web-Based Survey (2011-2014) dataset were utilized. In total, 206 North Korean adolescent defectors were selected, and for the control group, 618 matched South Korean adolescents were selected. Frequency analysis was used to determine the place of birth and nationality of the parents, chi-square tests were used to compare the general characteristics of the North and South Korean subjects, and multivariate logistic regressions were conducted to compare the health behavior of the two sets of subjects. To determine the factors associated with depression in the North Korean subjects, a logistic regression was performed. RESULTS: The North Korean adolescents reported higher current smoking (adjusted odds ratio [aOR], 2.54; 95% confidence interval [CI], 1.48 to 4.35), current drinking (aOR, 1.85; 95% CI, 1.15 to 2.99), and drug use rates (aOR, 10.99; 95% CI, 4.04 to 29.88) than did the South Korean adolescents. The factors associated with depression in the North Korean adolescents were current smoking (aOR, 6.99; 95% CI, 1.62 to 30.06), lifetime drinking experience (aOR, 5.32; 95% CI, 1.51 to 18.75), and perceived stress (aOR, 4.74; 95% CI, 1.74 to 12.90). CONCLUSION: There were differences in health behavior between the North and South Korean adolescents. A specialized approach for North Korean adolescent defectors is required to promote proper health behavior and adaptation to South Korean society.

Relationship between dietary factors and bisphenol a exposure: the second Korean National Environmental Health Survey (KoNEHS 2012-2014).

BACKGROUND: This study was aimed at finding out the exposure level of bisphenol A (BPA), a well-known endocrine disruptor, in relation to dietary factors using a data representing the Korean general population. METHODS: This study was performed on 5402 adults aged 19 years and older based on the Second Korean National Environmental Health Survey (KoNEHS 2012-2014). The data analyzed urinary BPA concentration in relation to socio-demographic variables, health behavior-related variables, and dietary factor-related variables. Odds ratio (OR) was calculated through a logistic regression analysis after dividing the participants into high BPA exposure group and low BPA exposure group based on the top 75 percentile concentration. The logistic regression analysis was carried out considering the appropriate sample weight, stratification, and clustering of the second KoNEHS sample design. RESULTS: The group drinking bottled water at home and the group using zip-top bags/plastic bags showed significantly higher urinary BPA concentration in female. OR tends to increase as the intake frequency of frozen food increased and OR of frozen food consumption of more than once a week was 1.48 (95% confidence interval (CI) 1.02-2.24) for male and the group drinking bottled water showed significantly higher OR of 1.45 (95% CI 1.06-2.17) after adjusting the related factors for female. CONCLUSIONS: BPA levels were high in female using bottled water and in male consuming frozen food, and therefore bottled water and frozen food need to be avoided to reduce BPA levels.

The relationship between night work and involuntary weight change: data from the fifth Korea National Health and Nutrition Examination Survey (KNHANES 2010-2012).

BACKGROUND: Previous studies on the association between shift or night work and weight change have been focused on finding the risk of weight gain caused by shift or night work. In this study, we aimed to reveal the risk of weight gain and weight loss associated with night work by using a nationwide representative data. METHODS: This study was performed on 1605 full-time wage workers between the age of 20 and 69 based on the fifth Korea National Health and Nutrition Examination Survey (KNHANES 2010-2012). The association between night work and involuntary weight change in the previous year was divided into the categories of weight gain and weight loss and studied with modifications in socio-demographic variables, health behavior-related variables, and occupational characteristic variables. RESULTS: The participants working in night work accounted for 10.6 % of total study participants (male; 11.9 %, female 7.4 %). Workers who worked more than 48 hours per week on average accounted for 41.6 % of the total study participants (male; 46.3 %, female 29.1 %). Odds ratio (OR) of weight loss associated with night work in male workers was 0.34 (95 % confidence interval (CI) 0.16-0.76) after controlling for several related factors. OR of weight loss associated with night work in female workers with long working hours was 1.95 (95 % CI 0.47-80.86) and that of weight gain was 2.83 (95 % CI 0.12-69.83) after adjusting associated factors. CONCLUSIONS: In this cross-sectional study with national representative sample, night work may lower the risk of weight loss in male workers and induce weight change (weight loss or weight gain) in female workers with long working hours. Therefore, future studies with cohort study design for night workers are needed to reveal the mechanisms and health effects of weight change associated with night work and establish proper management solutions with health and labor policies for Korean night workers.

The association between long working hours and hearing impairment in noise unexposed workers: data from the 5th Korea National Health and Nutrition Examination Survey (KNHANES 2010-2012).

BACKGROUND: This study is aimed at finding out the relationship between long working hours, one of major job stress elements, and hearing impairment in unexposed workers to occupational and environmental noise. METHODS: This study was performed on 1628 regular, full-time wage workers between the age of 25-64 who indicated in the survey of having no experience of exposure to noise, normal otoscopic findings, and not suffering from diabetes based on the data from the fifth Korea National Health and Nutrition Examination Survey (KNHANES 2010-2012). The average working hours per week was categorized into 40 h and lower group, more than 40 to 48 h group, more than 48 to 60 h group, and more than 60 h group. The groups were defined as suffering from low or high frequencies hearing impairment if the average hearing threshold for 0.5, 1, 2 kHz or 3, 4, 6 kHz in both ears exceeds 25 dB based on the pure tone audiometry. The association between average weekly working hours and hearing impairment was analyzed using logistic regression after gender stratification. RESULTS: The prevalences of low and high frequencies hearing impairment in male workers were 4.3 and 28.6 %, respectively, which were much higher than female's prevalence of 2.7 and 11.1 %. For male workers, no significant association was found between average weekly working hours and low and high frequencies hearing impairment. For female workers, odds ratios (OR) of low and high frequencies hearing impairment were 4.22 (95 % confidence interval (CI) 1.09-16.27) and 4.49 (95 % CI 1.73-11.67), respectively, after controlling for several related factors, such as, age, Body Mass Index (BMI), socio-economic status, health-related behavioral, and occupational characteristics variables, in the final model in the group working more than 60 h compared to the group working 40 h and lower. In addition, a dose-response relationship was observed that ORs of low and high frequencies hearing impairment were increased according to increasing average weekly working hours. CONCLUSIONS: The association between long working hours and hearing impairment in both low and high frequencies was significant in Korean female workers with a dose-response relationship. Therefore, the law to change the culture of long working hours should be enacted in order to protect the workers' health and improve the quality of life in Korean workers.

Body Mass Index and Mortality according to Gender in a Community-Dwelling Elderly Population: The 3-Year Follow-up Findings from the Living Profiles of Older People Surveys in Korea.

BACKGROUND: Body mass index is widely regarded as an important predictor of mortality. The purpose of this study was to investigate the relationship between body mass index and mortality and to compare community-dwelling elderly people in South Korea according to sex. METHODS: Data were collected from the 2008 and 2011 Living Profiles of Older People Surveys, which comprised 10,613 community-living South Korean men and women aged 65 years or older. The participants were stratified into five groups according to body mass index as defined by the World Health Organization guidelines. The sociodemographic characteristics of participants and mortality rates were compared across the body mass index groups. RESULTS: The highest survival rates were observed in men with a body mass index of 25.0-29.9 kg/m2. A similar trend was observed in women, but it was not statistically significant. After adjusting for covariates, this association was also found in men across all BMI index groups, but not in women. CONCLUSION: This study supports previous findings that overweight or mild obesity is associated with the lowest mortality and suggests that the current categories of obesity require revision. Furthermore, the absence of statistically significant findings in the female cohort suggests that body mass index is not a suitable predictor of mortality in women and that an alternative is required.

The Association between Long Working Hours and Self-Rated Health.

OBJECTIVES: This study was conducted to determine the number of hours worked per week by full-time wage workers by using the data of the Korean Labor and Income Panel Study (KLIPS), which represents the domestic urban area household, and to determine the association between weekly working hours and the level of self-rated health. METHODS: We used data from the 11th KLIPS conducted in 2008. The subjects of this study were 3,699 full-time wage workers between the ages of 25 and 64 years. The association between weekly working hours and self-rated health was analyzed considering socio-demographic characteristics, work environment, and health-related behaviors. RESULTS: Among the workers, 29.7% worked less than 40 hours per week; 39.7%, more than 40 to 52 hours; 19.7%, more than 52 to 60 hours; and 10.9%, more than 60 hours per week. After controlling for socio-demographic variables, work environment-related variables, and health-related behavior variables, the odds ratio (OR) for poor self-rated health for the group working more than 40 hours and up to 52 hours was calculated to be 1.06 (95% confidence interval (CI), 0.89-1.27) when the group working less than 40 hours per week was considered the reference. The OR for the group working more than 60 hours was 1.42 (95% CI, 1.10-1.83) and that for the group working more than 52 hours and up to 60 hours was 1.07 (95% CI, 0.86-1.33). After stratification by gender and tenure, the OR of the female workers group and that of the group with a tenure of more than 1 year were found to be significantly higher than those of the other groups. CONCLUSIONS: This study showed that workers working more than 60 hours per week have a significantly higher risk of poor self-rated health than workers working less than 40 hours per week. This effect was more obvious for the female workers group and the group with a tenure of more than 1 year. In the future, longitudinal studies may be needed to determine the association between long working hours and various health effects in Korean workers.

Association between Bone Mineral Density and Sleep Duration in the Korean Elderly Population.

BACKGROUND: An association between sleep duration and a wide spectrum of diseases has been reported, but little is known about its relationship with bone mineral density (BMD). Previously conducted studies in Korea and abroad have reported results that are controversial. The present study sought to assess whether sleep duration can be considered an independent risk factor of osteoporosis. METHODS: We included participants over the age of 60 years with data on self-reported habitual sleep duration and BMD measured with dual X-ray absorptiometry. Comprehensive data on the study sample was obtained from the Korea National Health and Nutritional Survey performed from 2008 to 2010. Sex-stratified multiple regression analyses were conducted with adjustments for possible confounding factors. RESULTS: There was a significant inverse dose-dependent association between sleep duration and BMD measured at total hip, femur neck, and lumbar spine for women and total hip and femur neck for men. Sex-stratified regression analyses adjusted for age and body mass index revealed that sleep duration had a negative correlation with BMD at total hip and femoral neck for both women (ß = -0.0048; P = 0.0172 for total hip, ß = -0.0037; P = 0.0303 for femur neck) and men (ß = -0.0057; P = 0.0218 for total hip, ß = -0.0057; P = 0.0143 for femur neck). For women, the significance remained after further adjustment of confounding variables. CONCLUSION: Prolonged sleep duration appears to have a significant association with lower total hip and femur neck BMD in elderly women but not in elderly men.

The Relationship between Prevalence of Osteoporosis and Proportion of Daily Protein Intake.

BACKGROUND: The association between daily protein intake and osteoporosis is still controversial and only a few studies have explored the issue in Korea. This study investigated the relationship between daily protein intake and the prevalence of osteoporosis in Korean adults. METHODS: This study analyzed data extracted from the Korean National Health and Nutrition Examination Survey 4. Participants were aged 19 years or older and had never been treated for osteoporosis. The percentage of calories coming from protein intake was assessed by 24-hour recall method, and participants were divided into three groups according to recommended daily dietary protein intake as a proportion of total daily calories (i.e., <10%, 10%-20%, and >20%). A lumbar or femur neck bone mineral density T-score less than -2.5 was indicative of the presence osteoporosis. The influence of daily protein intake on the prevalence of osteoporosis was analyzed. RESULTS: IN BOTH SEXES, THE GROUP WITH THE HIGHEST PROTEIN INTAKE HAD SIGNIFICANTLY LOWER ODDS OF DEVELOPING LUMBER OSTEOPOROSIS WHEN COMPARED TO THE GROUP WITH THE LOWEST PROTEIN INTAKE, AFTER ADJUSTING FOR ASSOCIATED FACTORS (FEMALES: odds ratio [OR], 0.618; 95% confidence interval [CI], 0.610 to 0.626; P for trend <0.001; males: OR, 0.695; 95% CI, 0.685 to 0.705; P for trend <0.001). CONCLUSION: Sufficient daily protein intake lowered the prevalence of osteoporosis in Korean adults. Further prospective studies are necessary to verify the preventive effect of adequate protein intake on osteoporosis.

Coffee Consumption and Stroke Risk: A Meta-analysis of Epidemiologic Studies.

BACKGROUND: Coffee is one of the most widely consumed beverages in the world, and contains caffeine and phenolic compounds. Many studies on the association between coffee consumption and risk of stroke have been reported, however, more research is needed to further explore many studies' inconsistent results. Therefore, we conducted a meta-analysis to verify the relationship between coffee consumption and stroke. METHODS: We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library, using the keywords "coffee" or "caffeine" for the exposure factors, and "transient ischemic attack" or "stroke" or "acute cerebral infarction" or "cardiovascular events" for the outcome factors. We included prospective cohort and case-control studies published between 2001 and July 2011 in this review. The search was limited to English language. RESULTS: Among 27 articles identified for this review, only 9 studies met the inclusion criteria, all of which were cohort studies. When using all cohort studies, the pooled relative risk (RR) of stroke for the highest vs. lowest category of coffee consumption was 0.83 (95% confidence interval [CI], 0.76 to 0.91). When subgroup analysis was performed, for Europeans, increased coffee drinking showed a preventive effect on stroke occurrence with RR 0.82 (95% CI, 0.74 to 0.92); RR for women 0.81 (95% CI, 0.70 to 0.93); for ischemic stroke 0.80 (95% CI, 0.71 to 0.90); and for those drinking 4 cups or more per day 0.83 (95% CI, 0.75 to 0.91). CONCLUSION: We found that coffee consumption of 4 cups or more per day showed a preventive effect on stroke in this meta-analysis.

Health-related Quality of Life and Related Factors in Full-time and Part-time Workers.

BACKGROUND: There has been a rapid increase in the number of part-time workers in Korea with little information available on associated changes in quality of life. This study was designed to compare part-time and full-time workers in terms of the quality of life and related factors. METHODS: Data were extracted from the 4th Korea National Health and Nutrition Examination Survey, conducted in 2008. Of the 1,284 participants selected, 942 were females (range, 20 to 64 years). Based on the information provided by self-administered questionnaire, subjects were categorized according to the working pattern (full-time and part-time) and working hours (<30 and ≥30 hours). Differences in socio-demographic characteristics, health-related behaviors, and job characteristics were assessed by t-test and chi-square test. EuroQol-five dimensions (EQ-5D) index was implemented in order to measure the quality of life. Differences in the EQ-5D index scores between the groups were compared by t-test, stepwise multivariate logistic regression analyses. RESULTS: Quality of life did not differ by work patterns. In males, the Organization for Economic Cooperation and Development part-time group was associated with poorer quality of life (odds ratio [OR], 0.49; P = 0.028). For both sexes, the non-stress group was linked with superior quality of life in comparison to the stress group (OR, 2.64; P = 0.002; OR, 2.17; P < 0.001). Female employees engaged in non-manual labor had superior quality of life than those engaged in manual labor (OR, 1.40; P = 0.027). CONCLUSION: This study concludes that working less than 30 hours per week is related to lower quality of life in comparison to working 30 hours or more in male employees in Korea.

Trends of the New Outpatients in a University-based Family Practice.

BACKGROUND: Analysis of outpatient visits to primary care offers essential data for residency training by understanding 'reasons for encounter (RFE).' This study was designed to recognize the effect of population aging on demographic characteristics and RFEs. METHODS: We included all patients who had visited family practice clinic in Kyung Hee University Hospital in Seoul during each first 5 working days of September, October, and November in 2001 and 2008. New patients included those who hadn't visited within the last 6 months or more. Information on each patient's age, sex, and reason for encounter was obtained from the electronic medical record. The RFEs were compared using International Classification of Primary Care (ICPC)-2-E. RESULTS: Mean age of overall outpatients was 50.5 and 52.4 years in 2001 and 2008 respectively. The number of new outpatient visits increased from 215 (21.3%) to 326 (29.7%) between 2001 and 2008 (P < 0.001) along with the number of patients aged 65 or more from 7.4% to 12.0% (P = 0.08). Mean age of established patients was 52.5 and 56.9 years (P < 0.001), and the patients aged 65 or more was 14.1% and 35.8% (P < 0.001) in 2001 and 2008 respectively. Analysis by ICPC-2-E revealed a decrease in chapter A in 2008 (P = 0.03) and an increase in chapter F, L, and X (P = 0.01, 0.003, <0.001). Component 1 had increased (P = 0.01), and component 2 had decreased (P = 0.04) in proportion. CONCLUSION: Changes in population composition have brought a shift of the distribution of age in outpatients, more significantly in follow-up patients. Comparison by ICPC-2-E showed changes in RFEs of new patients between 2001 and 2008.