Correction: Min, J.-Y.; Min, K.-B. Comparisons of Two Bioelectrical Impedance Devices and Manual versus Sensor-Based Short Physical Performance Batteries for Assessment of Muscle Mass and Physical Performance. Sensors 2023, 23, 6026.

There were five errors in the original article [...].

Association between health-related quality of life and heart rate variability in elderly individuals with cognitive impairment in Korea: cross-sectional study.

BACKGROUND: Cognitive impairment, a characteristic and prior stage of dementia, is a serious public health concern in Korea a country with rapidly aging population. In a neurovisceral integration model, cognitive ability is connected to emotional and autonomic regulation via an interconnection in the brain, which may be associated with health-related quality of life (HRQoL). METHODS: This study investigated the association between the HRQoL and the autonomic nervous system (ANS) via EuroQoL-5 Dimension (EQ-5D) and heart rate variability (HRV) among 417 patients who visited the Neurology Department in Veterans Health Service Medical Center, Seoul, South Korea. RESULTS: The mean age of 275 patients in the cognitive impairment group (CIG) was higher than that of 142 patients in the normal cognition group (NCG) (74.85 years vs. 72.96 years, p < 0.001). In a generalized linear model with a beta coefficient (ß), an increase in HRQoL was associated with higher HRV levels was observed only in CIG (CIG: the standard deviation of all NN intervals (SDNN) (ln, ms): ß = 0.02, p = 0.007; Total power spectral density (TP) (ln, ms2): ß = 0.01, p = 0.007; High frequency (HF) (ln, ms2): ß = 0.01, p = 0.015; Low frequency (LF) (ln, ms2): ß = 0.01, p = 0.003) (NCG: SDNN (ln, ms): ß = 0.01, p = 0.214; TP (ln, ms2): ß = 0.01, p = 0.144; HF (ln, ms2): ß = 0.00, p = 0.249; LF (ln, ms2): ß = 0.01, p = 0.294). CONCLUSIONS: We found a significant association between HRQoL and HRV in Korean elders with cognitive impairment. However, this study is cross-sectional, so we cannot define direct causation. Further studies are needed to support our findings and to elucidate the biological mechanisms underlying these associations, especially in people cognitively impaired.

Sex differences in the association between sarcopenia and mild cognitive impairment in the older Korean population.

BACKGROUND: A link between sarcopenia and cognitive function has been proposed and is supported by several investigations. Nevertheless, the sex-linked relationship between these two diseases has been scarcely investigated. This cross-sectional study investigated sex differences in the association between sarcopenia and mild cognitive impairment. METHODS: We included all 286 participants aged 60 years or older with MCI who visited the Department of Neurology at Veterans Health Service Medical Center in South Korea from January to December 2021. The diagnosis of MCI was confirmed by two neurologists based on the participants' neuropsychological test scores. Diagnosis of sarcopenia was based on the algorithm of Asian Working Group for Sarcopenia (AWGS) 2019 including bioelectrical impedance analysis and handgrip strength, and cognitive function was assessed using Seoul Neuropsychological Screening Battery Core (SNSB-C) test. RESULTS: Among the 286 participants, 171 and 112 were men and women. After adjustment for potential covariates including APOE genotype, in women participants, there were significant associations between diagnosis of sarcopenia and MCI (OR = 4.72, 95%CI [1.39-15.97]), while there was no significant relationship in men participants. In eight subdomains of SNSB-C, we also found that women participants with sarcopenia demonstrated a significant memory decline (OR = 3.21, 95%CI [1.01-10.19]) as compared with the reference women group without sarcopenia after adjusting all covariates mentioned above. No significant association between any SNSB-C subdomain and MCI was demonstrated in men participants. CONCLUSIONS: We demonstrated that there was a different relationship between sarcopenia and MCI by sex and that sarcopenia may affect the cognitive subdomain differently by sex. These results imply that, with regard to cognitive function, maintaining muscle function and muscle mass might be more crucial for women than for men.

Telecommuting-related health outcomes during the COVID-19 pandemic in South Korea: a national population-based cross-sectional study.

BACKGROUND: Telecommuting has expanded greatly during the COVID-19 pandemic. Since the advent of remote working from home, there has been an ongoing controversy about the positive or negative health-related impact of telecommuting. This study aimed to investigate change in the occupational health risk in South Korean workers involved in telecommuting during the pandemic period compared to daily commuters. METHODS: A population-based cross-sectional study of South Korean workers using the secondary data from the 6th Korean Working Conditions Survey (2020-2021) was designed. A total of 12,354 white-collar wage employees were selected as the study sample. Telecommuting, depression, anxiety, insomnia, fatigue, musculoskeletal pain, headache-eye strain, absenteeism, and presenteeism were measured by self-reported data. Multiple logistic regression models, including gender stratification analysis, were used to estimate the adjusted odds ratio (AOR) with a 95% confidence interval (CI) for the health outcomes of telecommuters. RESULTS: Among the study population, 338 males and 318 females were reported to be telecommuters. The entirely adjusted regression model showed a positive association between telecommuting and anxiety (AOR = 2.82; 95% CI, 1.93-4.10), insomnia (AOR = 1.93; 95% CI, 1.27-2.92), fatigue (AOR = 1.76; 95% CI, 1.30-2.37), musculoskeletal pain (AOR = 1,76; 95% CI, 1.33-2.32), headache-eye strain (AOR = 1.94; 95% CI, 1.48-2.54), presenteeism (AOR = 1.66; 95% CI, 1.20-2.28) respectively. Gender difference was identified in that only female telecommuters had a higher risk of depression (AOR = 1.62; 95% CI, 1.04-2.53) and insomnia (AOR = 2.07; 95% CI, 1.26-3.41) than daily commuters in the adjusted model. CONCLUSION: Telecommuting was significantly associated with an increased risk of various health problems among South Korean workers and females were identified as a more vulnerable group. Although further research is required to ascertain the causal relationship, public health intervention should be considered to prevent the negative effects of telecommuting.

Comparisons of Two Bioelectrical Impedance Devices and Manual versus Sensor-Based Short Physical Performance Batteries for Assessment of Muscle Mass and Physical Performance.

The assessment of muscle mass and physical performance is essential for the diagnosis of sarcopenia. This study examined the validity of bioimpedance analysis (BIA) and a sensor-based short physical performance battery (SPPB) device for analyzing appendicular skeletal muscle mass (ASM) and physical performance. Forty-one older adults were measured for ASM and physical performance with two BIA devices (InBody770 vs. T-SCAN PLUS III) and two SPPB devices (manual mSPPB vs. sensor-based sSPPB). Validity statistics included the intraclass correlation coefficient (ICC) and Bland-Altman plots to examine the agreement of data from the BIA (InBody770 vs. T-SCAN PLUS III) and the SPPBs (mSPPB vs. sSPPB). There was a significant ICC for skeletal muscle mass between the T-SCAN PLUS III and InBody770 devices (ICC = 0.8822; p < 0.0001). The mSPPB and sSPPB values showed agreement across all components: 0.8654 for the total scores, 0.8879 for the walking speed, 0.8889 for the chair stand, and 0.6863 for the standing balance. No systemic bias was observed between the two methods for the BIA and SPPB devices. Measurements using the T-SCAN PLUS III and sSPPB seem to be highly correlated with the InBody770 and mSPPB devices in older adults and may be valid for assessing muscle mass and physical performance.

Association between serum klotho levels and cardiovascular disease risk factors in older adults.

BACKGROUND: Klotho deficiency is a significant predictor of cardiovascular disease (CVD)-related mortality and morbidity. However, research assessing the association between klotho and individual risk factors of CVD is limited. This study aimed to explore the association between circulating serum klotho levels and risk factors for CVD in adults. METHODS: We used the 2007-2016 National Health and Nutrition Examination Survey and included 13,154 participants for whom serum klotho levels were available. Body mass index (BMI), exercise, smoking status, alcohol consumption, hypertension, dyslipidemia, serum lipid parameters, and blood pressure were considered as CVD risk factors. RESULTS: Circulating klotho levels were negatively associated with being overweight (beta coefficient: - 22.609, p = 0.0025), obesity (beta coefficient: - 23.716, p = 0.0011), current smoking (beta coefficient: - 46.412, p < 0.0001), and alcohol consumption (beta coefficient: - 51.194, p < 0.0001). There was a positive association between serum klotho levels and no history of dyslipidemia (beta coefficient: 15.474, p = 0.0053). Serum klotho levels were significantly decreased by a unit increase in triglycerides (beta coefficient: - 0.117, p = 0.0006) and total cholesterol (beta coefficient: - 0.249, p = 0.0002). There was a significant non-linear relationship between serum klotho levels, triglycerides, and total cholesterol. CONCLUSIONS: Lower serum klotho levels are associated with certain CVD risk factors, including high BMI, smoking, alcohol consumption, and lipid parameters (triglycerides and total cholesterol). This study suggests that the soluble klotho level may be a potential marker for CVD risk.

Relationship between chronic exposure to ambient air pollution and mental health in Korean adult cancer survivors and the general population.

BACKGROUND: Although a significant association between air pollution and mental health has been identified, few studies have addressed this relationship based on cancer diagnosis. This study investigated whether associations between long-term air pollution and mental health conditions differ based on whether the individual has been diagnosed with cancer. METHODS: Nationally representative data were used and a total of 38,101 adults were included in the analyses. We assessed mental health factors such as perceived stress, depressive symptoms, and suicidal ideation, and analyzed the associations between these factors and individuals' annual average exposure to air pollutants, including particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), nitrogen dioxide, sulfur dioxide, and carbon monoxide. RESULTS: Compared with the general population, PM10 exposure in cancer survivors predicted a higher risk of depressive symptoms (odds ratio [OR] =1.34; 95% confidence interval [CI] = 1.06-1.69) and suicidal ideation (OR = 1.29; 95% CI = 1.01-1.64). Notably, the statistically significant relationship between PM10 exposure and suicidal ideation in cancer survivors disappeared after further adjustment for depressive symptoms (p = 0.3103). This pattern was also observed in the result of propensity score-matched analysis for comparison between cancer survivors and the general population. CONCLUSIONS: This study provides the first evidence that cancer survivors with depressive symptoms may be more susceptible to suicidal ideation in the context of persistent PM10 exposure.

Disparities in infant mortality by payment source for delivery in the United States.

In this study, we hypothesized that infant mortality varies among health insurance status. Furthermore, we examined whether there are racial and ethnic disparities in the association between infant death and payment source for delivery. Our study used US national linked birth and infant death data for 2013 and 2017 collected by the National Center for Health Statistics and included 3,311,504 and 3,218,168 live births for each year. The principal source of payment for delivery was classified into three groups: Medicaid, private insurance, and self-payment. The outcome measures were infant mortality, neonatal mortality, and postneonatal mortality. Subgroup analysis for race and ethnicity was also performed. Overall infant mortality was lower in mothers who paid with private insurance than in those who paid with Medicaid insurance (RR = 0.87, 95% CI 0.84-0.90 in 2013; RR = 0.91, 95% CI 0.87-0.94 in 2017), but it was higher in self-paid women than in Medicaid-insured women at delivery (RR = 1.25, 95% CI 1.17-1.33 in 2013; RR = 1.16, 95% CI 1.08-1.24 in 2017). Non-Hispanic black (RR = 1.67, 95% CI 1.47-1.90 in 2013; RR = 1.16, 95% CI 1.00-1.35 in 2017) and Hispanic (RR = 1.30, 95% CI 1.17-1.44 in 2013; RR = 1.22, 95% CI 1.09-1.36 in 2017) mothers with self-payment had a higher risk for infant mortality than those with Medicaid at delivery. Newborns whose mothers have no health insurance would be more vulnerable to infant mortality than Medicaid beneficiaries, and non-white ethnic groups with self-payment would have an elevated risk of infant mortality among other racial and ethnic groups.

Serum sodium in relation to various domains of cognitive function in the elderly US population.

BACKGROUND: Recent evidence suggests that sodium imbalances may be associated with cognitive impairment; however, the association between specific domains of cognition remains unclear. This study examines the association between serum sodium levels and immediate and delayed verbal memory as measured by the CERAD Word Learning Test (CERAD WLT), executive function as measured by the Animal Fluency test (AFT), and sustained attention, working memory, and processing speed as measured by the Digit Symbol Substitution test (DSST) in the elderly population of the US aged 60 and older who participated in the 2011-2014 National Health and Nutrition Examination Surveys (n = 2,541). METHODS: Cognitive function tests were performed by trained interviewers and sodium levels were measured using indirect ion selective electrode methodology. RESULTS: After adjusting for all covariates, quintiles of CERAD WLT scores showed significant positive associations with log-transformed sodium levels (Immediate recall (IR) ß = 4.25 (SE = 1.83, p-value 0.027); Delayed recall (DR) ß = 6.54 (SE = 1.82, p-value 0.001)). Compared to normal sodium levels, hyponatremia was significantly associated with lower CERAD WLT-IR (ß = -0.34, SE = 0.15, p-value 0.035) and CERAD WLT-DR scores (ß -0.48, SE = 0.10, p-value < 0.001) and showed borderline significance with AFT scores (ß = = -0.38, SE = 0.19, p-value 0.052). Hypernatremia did not show any significant relationships with cognitive test scores, compared to normal sodium levels. CONCLUSIONS: Our cross-sectional study showed that lower sodium levels were associated with cognitive change, especially regarding memory and executive function.

Association between income levels and prevalence of heat- and cold-related illnesses in Korean adults.

BACKGROUND: Given that low income worsens health outcomes, income differences may affect health disparities in weather-related illnesses. The aim of this study was to investigate the association between income levels and prevalence of heat- and cold-related illnesses among Korean adults. METHODS: The current study comprised 535,186 participants with all variables on income and health behaviors. Patients with temperature-related illnesses were defined as individuals with outpatient medical code of heat- and cold-related illnesses. We categorized individual income into three levels: "low" for the fourth quartile (0-25%), "middle" for the second and the third quartiles (25-75%), and "high" for the first quartile (75-100%). To examine income-related health disparities, Cox proportional hazard regression was performed. Hazard ratios (HRs) and 95% CI (confidence interval) for heat- and cold-related illnesses were provided. The model adjusted for age, sex, smoking status, alcohol drinking, exercise, body mass index, hypertension, hyperglycemia, and local income per capita. RESULTS: A total of 5066 (0.95%) and 3302 (0.62%) cases identified patients with heat- and cold-related illnesses, respectively. Compared with high income patients, the adjusted HR for heat-related illnesses was significantly increased in the low income (adjusted HR = 1.103; 95% CI: 1.022-1.191). For cold-related illnesses, participants with low income were likely to have 1.217 times greater likelihood than those with high income (95% CI: 1.107-1.338), after adjusting for other covariates. In the stratified analysis of age (20-64 years and over 65 years) and sex, there was no difference in the likelihood of heat-related illnesses according to income levels. On the other hand, an HR for cold-related illnesses was higher in patients aged 20 to 64 years than in those aged over 65 years. Male with low income had also a higher HR for cold-related illnesses than female with low income. CONCLUSIONS: Our results showed that heat- or cold-related illnesses were more prevalent in Koreans with low income than those with high income. Strategies for low-income subgroups were needed to reduce greater damage due to the influence of extreme temperature events and to implement effective adaptation.

Increased cold injuries and the effect of body mass index in patients with peripheral vascular disease.

BACKGROUND: Exposure to extremely or moderate low temperatures is associated with increased morbidity and mortality risk. Peripheral vascular disease (PVD) is a slow and progressive circulation disorder. Given that cold temperature causes constriction of the small arteries and veins in the skin, patients who suffer from peripheral circulation problems, like PVD, may be vulnerable to cold injuries. This study aimed to investigate the association between PVD and cold-induced injuries in the winter among Korean adults. We further analyzed the association stratified by body mass index (BMI) classification. METHODS: We used the 2002-2015 National Health Insurance Service-National Sample Cohort data and included a total of 535,186 adults as the study population. Patients with underlying PVD were identified by ICD-10 code I73. Cold-related illnesses were defined by ICD-10 codes (T690, T691, T698, T699, T330 ~ T339, T340 ~ T349, and T350 ~ T357). Body mass index (BMI) was categorized into underweight, normal weight, overweight, and obese. RESULTS: A total of 23.21% (n = 124,224) were PVD patients, and 0.59% (n = 3154) had cold-induced injuries. PVD patients were more likely to be diagnosed with cold injuries, but it was valid only in the underweight or normal weight groups. After adjusting for age, sex, income, cigarette smoking, alcohol consumption, regular exercise, high blood pressure, and hyperglycemia, PVD patients had a significantly increased odds ratio (OR) for cold injuries [adjusted OR = 1.11; 95% confidence intervals (95% CI): 1.01-1.21]. Increased OR for cold injuries in PVD patients was also observed in adults (adjusted OR = 1.14; 95% CI: 1.03-1.25 in Model 2), but not in the elderly. When we classified study subjects into the four BMI groups, the adjusted OR of cold injuries in PVD patients was significant in the underweight group (OR = 1.83; 95% CI, 1.26-2.66) and normal weight group (OR = 1.15; 95% CI, 1.03-1.27), not in those with overweight and obese. In adults, a consistent result was found in adults in the underweight group (OR = 1.63; 95% CI, 1.08-2.47 in Model 2) and normal weight group (OR = 1.19; 95% CI, 1.07-1.33 in Model 2). In the elderly, the adjusted OR for cold injuries was only significant in the underweight group (OR = 3.37; 95% CI, 1.08-10.53 in Model 2). CONCLUSIONS: We found a significant association between PVD and cold-induced injuries in the general population. BMI modified the association. Thus, the association observed appears to be clinically applicable to PVD patients being low to normal BMI.

Topic Modeling of Social Networking Service Data on Occupational Accidents in Korea: Latent Dirichlet Allocation Analysis.

BACKGROUND: In most industrialized societies, regulations, inspections, insurance, and legal options are established to support workers who suffer injury, disease, or death in relation to their work; in practice, these resources are imperfect or even unavailable due to workplace or employer obstruction. Thus, limitations exist to identify unmet needs in occupational safety and health information. OBJECTIVE: The aim of this study was to explore hidden issues related to occupational accidents by examining social network services (SNS) data using topic modeling. METHODS: Based on the results of a Google search for the phrases occupational accident, industrial accident and occupational diseases, a total of 145 websites were selected. From among these websites, we collected 15,244 documents on queries related to occupational accidents between 2002 and 2018. To transform unstructured text into structure data, natural language processing of the Korean language was conducted. We performed the latent Dirichlet allocation (LDA) as a topic model using a Python library. A time-series linear regression analysis was also conducted to identify yearly trends for the given documents. RESULTS: The results of the LDA model showed 14 topics with 3 themes: workers' compensation benefits (Theme 1), illicit agreements with the employer (Theme 2), and fatal and non-fatal injuries and vulnerable workers (Theme 3). Theme 1 represented the largest cluster (52.2%) of the collected documents and included keywords related to workers' compensation (ie, company, occupational injury, insurance, accident, approval, and compensation) and keywords describing specific compensation benefits such as medical expense benefits, temporary incapacity benefits, and disability benefits. In the yearly trend, Theme 1 gradually decreased; however, other themes showed an overall increasing pattern. Certain queries (ie, musculoskeletal system, critical care, and foreign workers) showed no significant variation in the number of queries. CONCLUSIONS: We conducted LDA analysis of SNS data of occupational accident-related queries and discovered that the primary concerns of workers posting about occupational injuries and diseases were workers' compensation benefits, fatal and non-fatal injuries, vulnerable workers, and illicit agreements with employers. While traditional systems focus mainly on quantitative monitoring of occupational accidents, qualitative aspects formulated by topic modeling from unstructured SNS queries may be valuable to address inequalities and improve occupational health and safety.

Impact of hospital size on the outcomes of appendectomy in children: an analysis of a comprehensive nationwide pediatric dataset.

PURPOSES: The purpose of this study was to investigate the outcomes after appendectomy in children according to hospital size. METHODS: The records of 11,565 patients with the diagnosis-related group code for appendectomy were extracted from HIRA-Pediatric Patient Sample from 2012 to 2016. The number of hospital visits and the length of stay in hospital within 30 days after appendectomy were analyzed. RESULTS: Patients who were treated at large-sized hospitals were more likely to be younger, more likely to reside in metropolitan areas, and tended to receive laparoscopic surgery. The number of hospital visits within 30 days in patients managed by medium- and large-sized hospitals decreased in comparison to small-sized hospitals. The length of hospital stay in large-sized hospitals was decreased in comparison to small- and medium-sized hospitals. A subgroup analysis revealed that complicated appendectomy did not have a significant impact on the difference in the length of hospital stay between hospital sizes. CONCLUSION: The number of hospital visits and the length of hospital stay was higher in small-sized hospitals in comparison to large-sized hospitals. Appendectomy performed in the larger hospital showed better outcomes in pediatric patients. We recommend that pediatric surgical procedures be performed in large hospitals, and that proper incentives be given for procedures to be performed by pediatric specialists.

Outcomes after aortic aneurysm repair in patients with history of cancer: a nationwide dataset analysis.

BACKGROUND: Synchronous cancer in patients with abdominal aortic aneurysm (AAA) increases morbidity and mortality after AAA repair. However, little is known about the impact of the history of cancer on mortality after AAA repair. METHODS: Patients with intact AAA who were treated with endovascular aneurysm repair or open surgical repair were selected from the Health Insurance and Review Assessment data in South Korea between 2007 and 2016. Primary endpoints included the 30- and 90-day mortality and long-term mortality after AAA repair. The Cox proportional hazards models were constructed to evaluate independent predictors of mortality. RESULTS: A total of 1999 patients (17.0%, 1999/11785) were diagnosed with cancer prior to the AAA repair. History of cancer generally had no effect in short-term mortality at 30 and 90 days. However, short-term mortality rate of patients with a history of lung cancer was more than twice that of patients without it (3.07% vs. 1.06%, P = 0.0038, 6.14% vs. 2.69%, P = 0.0016). Furthermore, the mortality rate at the end of the study period was significantly higher in AAA patients with a history of cancer than in those without a history of cancer (21.21% vs. 17.08%, P < .0001, HR, 1.31, 95% CI, 1.17-1.46). CONCLUSIONS: The history of cancer in AAA patients increases long-term mortality but does not affect short-term mortality after AAA repair. However, AAA repair could increase both short- and long-term mortality in patients with lung cancer history, and those cases should be more carefully selected.

Physical and mental health problems of self-employed small business owners in South Korea.

BACKGROUND: Self-employed business owners in Korea make up one-quarter of the working population, and half of those who are self-employed are in micro and small businesses. Compared to the significant research interest in business management and economics, to date, there has been little interest in the health of small business owners. We investigated the health status of self-employed small business owners compared to standard workers. METHODS: The third Korean Working Conditions Survey, which included a total of 32 630 adults aged 20 to 59 years, was analyzed. A small business was defined as an enterprise with between 0 and 4 workers. Standard employment included full-time employment with a permanent or 1-year contract. Health outcomes included eight types of physical health and mental health problems assessed using the WHO-5 Wellbeing Index. RESULTS: Small business groups were found to have an increased prevalence of depression after controlling for all potential covariates (odds ratio [OR] = 1.37; 95% confidence interval [CI] 1.29-1.47). In addition, the prevalence of work-related physical health problems was significantly higher among self-employed small business owners in a full adjusted model: backache (OR = 1.16; 95% CI, 1.06-1.26), muscular pains in upper limbs (OR = 1.19; 95% CI, 1.12-1.27), and muscular pains in lower limbs (OR = 1.14; 95% CI, 1.07-1.22). CONCLUSION: We found a positive association between small business entrepreneurs and increased prevalence of mental and physical illness in adults in the Republic of Korea.

Association between psychological and self-assessed health status and smartphone overuse among Korean college students.

BACKGROUND: Several studies suggest that subjective health status is closely related to various behavioral addictions, but there are few studies on smartphone overuse. AIM: This study investigated the associations between psychological and subjective health conditions and smartphone overuse in Korean college students. METHOD: A total of 608 college students participated in this study. We investigated the perceived psychological factors, such as stress, depression symptoms and suicidal ideation. Overall health status was evaluated with self-assessed items, including usual health condition and EuroQol-visual analog scales (EQ-VAS) score. Smartphone overuse was evaluated as the Korean Smartphone Addiction Proneness Scale. RESULTS: Students with psychotic anxiety (i.e. stress, depression and suicidal ideation) showed significant associations with smartphone overuse, indicating an approximately twofold increased risk compared to those without psychological anxiety (all p < 0.05). Students who reported feeling that their usual health is not good were more likely to overuse smartphones than those who are in good health (OR = 1.98; 95% CI = 1.22-3.21). The EQ-VAS score, which indicates current self-assessed health status, also showed a similar result with general health status (OR = 2.14; 95% CI = 1.14-4.02). CONCLUSION: Negative conditions in self-perceived emotional or overall health condition are associated with the increased likelihood of smartphone overuse in Korean college students.

Night noise exposure and risk of death by suicide in adults living in metropolitan areas.

BACKGROUND: Noise is defined as "sound that is unwanted, unpleasant, or harmful to health." It may induce negative emotions and mental health problems and even may leads to increased suicide risk. Little attention has been paid so far to a potential link between noise and suicide. We investigated the association between nighttime environmental noise and suicide death in adults in the Republic of Korea. METHODS: We analyzed the data from the National Health Insurance Service-National Sample Cohort, with a 4-year baseline (2002-2005) and an 8-year follow-up (2006-2013) assessment. A total of 155,492 adults constituted the study sample: younger adults (20-54 years, n = 124,994), or older adults (≥55 years, n = 30,498), and adults with mood and anxiety disorders (n = 34,615). Suicide death was defined as per International Classification of Diseases-10 code X60-X84. Data on nighttime noise were obtained from the National Noise Information System. RESULTS: During the study period, 315 (0.2%) died of suicide. The incidence of suicide per 100,000 person-years was 25.71. With interquartile range increases in nighttime noise, the adjusted hazard ratio (HR) for suicide death was significantly increased: 1.32 (95% confidence interval [CI]: 1.02-1.70) for younger adults, 1.43 (95% CI: 1.01-2.02) for older adults, and 1.55 (95% CI: 1.10-2.19) for adults with mental illness. In the penalized regression spline models, the HRs for suicide death were gradually increased with environmental noise levels, and the risk was the highest for adults with mental illness. CONCLUSIONS: We found a significant association between exposure to nighttime noise and the risk of suicide death in adults in the Republic of Korea.

Association between leukocyte telomere length and serum carotenoid in US adults.

PURPOSE: Telomere length is a biomarker for aging. It is known that oxidative stress can accelerate telomere shortening, whereas antioxidants can delay their shortening. Carotenoids as antioxidants are favorably associated with health- and aging-related diseases caused by oxidative stress, but their association with telomere length is less certain. We investigated the association between blood carotenoid levels and leukocyte telomere length in a representative sample of US adults. METHODS: We analyzed 3660 participants aged 20 years and older in the 1999-2002 National Health and Nutrition Examination Survey. The levels of carotenoids-alpha-carotene, beta-carotene (trans + cis), beta-cryptoxanthin, combined lutein/zeaxanthin, and trans-lycopene-were measured using high-performance liquid chromatography. The leukocyte telomere length (T/S ratio) was assayed using the quantitative polymerase chain reaction method. RESULTS: A doubling of blood alpha-carotene, beta-carotene (trans + cis), and beta-cryptoxanthin was associated with approximately 2 % longer telomeres. Compared with the lowest carotenoid quartile of alpha-carotene, beta-carotene (trans + cis), and beta-cryptoxanthin, telomere length for adults with the highest quartiles was significantly increased by 5-8 %. CONCLUSION: We found that increasing levels of blood carotenoid were significantly associated with longer leukocyte telomeres in US adults. High intake of carotenoid-rich food may play a role in protecting telomeres and regulating telomere length.

Interaction between the RGS6 gene and psychosocial stress on obesity-related traits.

Obesity is a major risk factor for chronic diseases and arises from the interactions between environmental factors and multiple genes. Psychosocial stress may affect the risk for obesity, modifying food intake and choice. A recent study suggested regulator of G-protein signaling 6 (RGS6) as a novel candidate gene for obesity in terms of reward-related feeding under stress. In this study, we tried to verify the unidentified connection between RGS6 and human obesity with psychosocial stress in a Korean population. A total of 1,462 adult subjects, who participated in the Korean Association Resource cohort project, were included for this analysis. Obesity-related traits including waist circumference, body mass index, and visceral adipose tissue were recorded. A total of 4 intronic SNPs for the RGS6 gene were used for this study. We found that interactions between SNP rs2239219 and psychosocial stress are significantly associated with abdominal obesity (p = 0.007). As risk allele of this SNP increased, prevalence of abdominal obesity under high-stress conditions gradually increased (p = 0.013). However, we found no SNPs-by-stress interaction effect on other adiposity phenotypes. This study suggests that RGS6 is closely linked to stress-induced abdominal obesity in Korean adults.

Blood cadmium levels and Alzheimer's disease mortality risk in older US adults.

BACKGROUND: Cadmium, a ubiquitous environmental pollutant, exhibits potential neurotoxic risk. Although compelling evidence suggests cadmium accumulation has a role in the formation of amyloid-ß plaques and neurofibrillary tangles, which are the hallmarks of Alzheimer's disease (AD) pathogenesis, the supporting evidence in humans is limited and conflicting. In this study, we investigated the association between blood cadmium levels and AD mortality among older adults by analyzing the prospective data from the 1999-2004 Third National Health and Nutrition Examination Survey (NHANES) and the Linked Mortality File. METHODS: The data were obtained from the 1999-2004 NHANES and the NHANES (1999-2004) Linked Mortality File. A total of 4,064 participants aged ≥60 years old with available blood cadmium data and no other missing information on their questionnaires at baseline were included in this study. AD was denoted as G30 based on the ICD-10 underlying causes of death. RESULTS: Of the 4,064 participants, 51 subjects died as a result of AD. Compared with participants with low blood cadmium levels (≤0.3 µg/L), those with high cadmium levels (>0.6 µg/L) exhibited a 3.83-fold (hazard ratio = 3.83; 95 % CI = 1.39-10.59) increased risk of AD mortality. In the Kaplan-Meier survival curves for cumulative AD mortality, higher levels of blood cadmium showed marginally significant association with increased mortality at baseline and in patients over 60 years of age (p = 0.0684). CONCLUSIONS: We observed a significant association between blood cadmium levels and AD mortality among older adults in the US. Our findings suggest that environmental exposure to cadmium may be a risk factor for AD.