Metabolically Healthy Obesity and Development of Chronic Kidney Disease: A Cohort Study.

BACKGROUND: The risk for chronic kidney disease (CKD) among obese persons without obesity-related metabolic abnormalities, called metabolically healthy obesity, is largely unexplored. OBJECTIVE: To investigate the risk for incident CKD across categories of body mass index in a large cohort of metabolically healthy men and women. DESIGN: Prospective cohort study. SETTING: Kangbuk Samsung Health Study, Kangbuk Samsung Hospital, Seoul, South Korea. PARTICIPANTS: 62 249 metabolically healthy, young and middle-aged men and women without CKD or proteinuria at baseline. MEASUREMENTS: Metabolic health was defined as a homeostasis model assessment of insulin resistance less than 2.5 and absence of any component of the metabolic syndrome. Underweight, normal weight, overweight, and obesity were defined as a body mass index less than 18.5 kg/m2, 18.5 to 22.9 kg/m2, 23 to 24.9 kg/m2, and 25 kg/m2 or greater, respectively. The outcome was incident CKD, defined as an estimated glomerular filtration rate less than 60 mL/min/1.73 m2. RESULTS: During 369 088 person-years of follow-up, 906 incident CKD cases were identified. The multivariable-adjusted differences in 5-year cumulative incidence of CKD in underweight, overweight, and obese participants compared with normal-weight participants were -4.0 (95% CI, -7.8 to -0.3), 3.5 (CI, 0.9 to 6.1), and 6.7 (CI, 3.0 to 10.4) cases per 1000 persons, respectively. These associations were consistently seen in all clinically relevant subgroups. LIMITATION: Chronic kidney disease was identified by a single measurement at each visit. CONCLUSION: Overweight and obesity are associated with an increased incidence of CKD in metabolically healthy young and middle-aged participants. These findings show that metabolically healthy obesity is not a harmless condition and that the obese phenotype, regardless of metabolic abnormalities, can adversely affect renal function. PRIMARY FUNDING SOURCE: None.

Sugar-sweetened carbonated beverage consumption and coronary artery calcification in asymptomatic men and women.

BACKGROUND: Sugar-sweetened carbonated beverage consumption has been linked to obesity, metabolic syndrome, type 2 diabetes, and clinically manifest coronary heart disease, but its association with subclinical coronary heart disease remains unclear. We investigated the relationship between sugar-sweetened carbonated beverage consumption and coronary artery calcium (CAC) in a large study of asymptomatic men and women. METHODS: This was a cross-sectional study of 22,210 adult men and women who underwent a comprehensive health screening examination between 2011 and 2013 (median age 40 years). Sugar-sweetened carbonated beverage consumption was assessed using a validated food frequency questionnaire, and CAC was measured by cardiac computed tomography. Multivariable-adjusted CAC score ratios and 95% CIs were estimated from robust Tobit regression models for the natural logarithm (CAC score +1). RESULTS: The prevalence of detectable CAC (CAC score >0) was 11.7% (n = 2,604). After adjustment for age; sex; center; year of screening examination; education level; physical activity; smoking; alcohol intake; family history of cardiovascular disease; history of hypertension; history of hypercholesterolemia; and intake of total energy, fruits, vegetables, and red and processed meats, only the highest category of sugar-sweetened carbonated beverage consumption was associated with an increased CAC score compared with the lowest consumption category. The multivariable-adjusted CAC ratio comparing participants who consumed ≥5 sugar-sweetened carbonated beverages per week with nondrinkers was 1.70 (95% CI, 1.03-2.81). This association did not differ by clinical subgroup, including participants at low cardiovascular risk. CONCLUSION: Our findings suggest that high levels of sugar-sweetened carbonated beverage consumption are associated with a higher prevalence and degree of CAC in asymptomatic adults without a history of cardiovascular disease, cancer, or diabetes.

Temperament and characteristics related to attention deficit/hyperactivity disorder symptoms.

OBJECTIVE: Adult attention deficit/hyperactivity disorder (ADHD) exhibits symptoms, such as attention deficit and impulsivity, that make it difficult for patients to manage social activities. In this study, we investigated the association of adult ADHD symptoms with temperament and character dimensions, taking into account possible sex interactions. METHOD: A total of 2917 (1462 males and 1455 females) college students completed the 140 5-point Likert items on the Temperament and Character Inventory-Revised Short version (TCI-RS) and the Attention Deficit/Hyperactivity Disorder Self-Rated Scale (ASRS). According to the ASRS score, subjects were classified into the control group, the inattentive ADHD symptom (IA) group, or the hyperactive/impulsive ADHD symptom (HI) group. Additionally, the scores of the four temperament dimensions and the three character dimensions were compared. RESULTS: In the IA and HI groups, the NS and HA levels of the temperament dimension were high and the PS level was low compared with the control group. In the character dimension, the levels of SD and CO were significantly lower in the ADHD groups than in the control group (P<0.001). Meanwhile, the ST level in the HI group was significantly higher than in the control group. In the regression analysis after age and gender correction, NS and SD in the IA group and NS, CO, and ST in the HI group were associated with adult ADHD symptoms. CONCLUSION: The current findings suggest that high novelty seeking may be related to adult ADHD symptoms in the temperament dimension. Furthermore, some character dimensions were associated with adult ADHD symptoms.

Relationship of sitting time and physical activity with non-alcoholic fatty liver disease.

BACKGROUND & AIMS: The goal of this study was to examine the association of sitting time and physical activity level with non-alcoholic fatty liver disease (NAFLD) in Korean men and women and to explore whether any observed associations were mediated by adiposity. METHODS: A cross-sectional study was performed on 139,056 Koreans, who underwent a health examination between March 2011 and December 2013. Physical activity level and sitting time were assessed using the validated Korean version of the international Physical Activity Questionnaire Short Form. The presence of fatty liver was determined using ultrasonographic findings. Poisson regression models with robust variance were used to evaluate the association of sitting time and physical activity level with NAFLD. RESULTS: Of the 139,056 subjects, 39,257 had NAFLD. In a multivariable-adjusted model, both prolonged sitting time and decreased physical activity level were independently associated with increasing prevalence of NAFLD. The prevalence ratios (95% CIs) for NAFLD comparing 5-9 and ⩾10 h/day sitting time to <5h/day were 1.04 (1.02-1.07) and 1.09 (1.06-1.11), respectively (p for trend <0.001). These associations were still observed in subjects with BMI <23 kg/m(2). The prevalence ratios (95% CIs) for NAFLD comparing minimally active and health-enhancing physically active groups to the inactive group were 0.94 (0.92-0.95) and 0.80 (0.78-0.82), respectively (p for trend <0.001). CONCLUSIONS: Prolonged sitting time and decreased physical activity level were positively associated with the prevalence of NAFLD in a large sample of middle-aged Koreans, supporting the importance of reducing time spent sitting in addition to promoting physical activity.

Metabolic syndrome, insulin resistance, and mammographic density in pre- and postmenopausal women.

Little is known about the association of metabolic syndrome (MetS) or insulin resistance (IR) with mammographic density, a strong risk factor for breast cancer. The goal of this study was to evaluate these associations in pre- and postmenopausal women. A cross-sectional study was performed in 73,974 adult women who underwent a comprehensive health screening examination that included a mammogram between 2011 and 2013 (mean age 42.6 years). MetS was defined according to the modified National Cholesterol Education Program Adult Treatment Panel III. IR was assessed with the homeostasis model assessment-insulin resistance (HOMA-IR). Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for dense breast were estimated using logistic regression models after adjustment for potential confounders. In premenopausal women, MetS and all its components except waist circumference were associated with dense breast. After adjustment for potential confounders, the OR (95% CI) for dense breast in women with MetS compared with those without MetS was 1.22 (1.06-1.39). In postmenopausal women, however, there was positive but non-significant association between MetS and dense breast. In both pre- and postmenopausal women, high blood glucose and IR were positively associated with dense breast. The OR (95% CI) for dense breast between the highest and lowest quartiles of HOMA-IR was 1.29 (1.20-1.39) for premenopausal women and 1.44 (1.05-1.97) for postmenopausal women. In a large sample of Korean women, MetS and IR were associated with mammographic dense breast, demonstrating that IR, a potentially modifiable risk factor, may increase breast cancer risk, possibly through high mammographic density.

Character profiles and life satisfaction.

BACKGROUND: There is a surge of interest in subjective well-being (SWB), which concerns how individuals feel about their happiness. Life satisfaction tends to be influenced by individual psychological traits and external social factors. The aim of this study was to examine the relationship between individual character and SWB. METHODS: Data from 3522 university students were analyzed in this study. Character profiles were evaluated using the Temperament and Character Inventory-Revised Short version (TCI-RS). Life satisfaction was assessed using the Satisfaction with Life Scale (SWLS). All statistical tests regarding the correlations between each character profile and life satisfaction were conducted using ANOVAs, t-tests, multiple linear regression models and correlation analyses. RESULTS: The creative (SCT) profile was associated with the highest levels of life satisfaction, whereas the depressive (sct) profile was associated with the lowest levels of life satisfaction. Additionally, high self-directedness, self-transcendence and cooperation were associated with high life satisfaction. The results of gender-adjusted multiple regression analysis showed that the effects of self-directedness were the strongest in the assessment of one's quality of life, followed by self-transcendence and cooperativeness, in that order. All of the three-character profiles were significantly correlated with one's quality of life, and the character profiles of TCI-RS explained 27.6% of life satisfaction in total. Among the three-character profiles, the self-directedness profile was most associated with life satisfaction. LIMITATIONS: Our study was cross-sectional, and self-reported data from students at a single university were analyzed. CONCLUSIONS: The results of this study showed that, among the character profiles, the effects of self-directedness were the strongest for predicting life satisfaction.

The Difference of Suicidal Ideation Between Shift Workers and Day Workers by Gender.

Shift work does not synchronize with the 24-hour human circadian rhythm, so shift workers experience various problems related to this disruption. This study investigated the relationship between suicidal risk and emotional difficulties such as depression and anxiety in shift workers according to gender. We analyzed data collected from 79,009 health checkup recipients. We checked psychosocial factors for different genders using the Chi-square test and t-tests. To examine the relationship between shift work and suicidal ideation, we estimated an odds ratio after adjustment for age, depression, and insomnia. There was no difference in terms of the risk of suicidal ideation between shift workers and day workers among women (adjusted odds ratio [AOR], 0.957; 95% confidence interval [CI], 0.826-1.109), whereas the risk of suicidal ideation was significantly higher for shift workers than for day workers among men (AOR, 1.157; 95% CI, 1.021-1.310). This study confirmed that associated factors of shift work-related suicidal ideation could act differently by gender. Shift work for women is generally associated with emotional difficulties such as depression and anxiety, whereas maladaptation to shift work may be related to suicidal ideation among men. A gender-specific suicide prevention approaches will be needed for shift workers.

Relationship between chronic kidney disease and risk of coronary heart disease in Korean men.

There have been many epidemiological researches of chronic kidney disease (CKD), accompanied by an increase in the incidence of coronary heart disease (CHD). However, as far as we know, little research has been done to examine the extent of the relationship between CKD and CHD as estimated by Framingham risk score (FRS) in Korean men. CKD was defined as either proteinuria or an eGFR of < 60 mL/min per 1.73 m(2). The FRS has been used to predict the 10-yr risk of coronary events and usually divided into three levels of risk < 10% (low), 10%-19% (intermediate) and ≥ 20% (high). We defined FRS ≥ 10% as more-than-a-moderate CHD risk group and FRS ≥ 20% as a high CHD risk group, respectively. After adjusting for covariates, multivariable-adjusted logistic regression analyses showed a strong statistical significant relationship between CKD and high risk of CHD (adjusted OR, 1.95 [95% CI, 1.32-2.87]). Dipstick urinalysis and eGFR can be readily measured in most clinical settings. The measurement of kidney function may represent a relatively inexpensive and efficient way to identify individuals at higher risk for CHD.

Problems with diagnostic criteria for humidifier disinfectant lung injury (HDLI): two cases of radiologically improved HDLI.

BACKGROUND: In Korea, to investigate the casual relationship between humidifier disinfectant and lung disease, four rounds of investigation and judgment were conducted. During this investigation, two adults who performed lung biopsy were recognized for their relevance between humidifier disinfectants and lung disease. At first, we did not think of the relationship to humidifier disinfectant because chest computed tomography (CT) finding of 2 cases were improved. However, they performed lung biopsy and it showed typical humidifier disinfectant lung injury (HDLI) pathologic findings, they could be recognized as HDLI. We report these cases here. CASE PRESENTATION: We selected 2 cases from the fourth-round investigation at Kangbuk Samsung Hospital. Patient of case 1 used humidifier disinfectants since September 2010. The patient was admitted 6 months later to the intensive care unit (ICU) due to severe dyspnea. Pathology following a lung biopsy revealed typical HDLI finding which was determined to be due to humidifier disinfectant exposure. Patient of case 2 used humidifier disinfectant from 2001 to 2008 for about 3 months each winter. The patient's cough and sputum production symptoms began in December of 2007. The patient was admitted to the respiratory medicine department due to worsening dyspnea. Pathology following a lung biopsy revealed typical HDLI finding. This was determined to have been caused by humidifier disinfectant exposure. CONCLUSIONS: Because the typical radiologic findings associated with HDLI can improve over time, it is necessary to consider the revision of current diagnostic criteria that the presence of radiologic findings is important.

Time-dependent association between metabolic syndrome and risk of CKD in Korean men without hypertension or diabetes.

BACKGROUND: The time-dependent association between metabolic syndrome and risk of chronic kidney disease (CKD) is not clear. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: The study cohort was composed of 10,685 healthy men without CKD, hypertension, or diabetes who participated in a health-checkup program at a large work site. PREDICTOR: Metabolic syndrome. OUTCOMES & MEASUREMENTS: CKD was defined as an estimated glomerular filtration rate (GFR) less than 60 mL/min/1.73 m(2). A standard Cox proportional hazards model and a time-dependent Cox model were used to calculate adjusted hazard ratios (HRs) in the CKD model. RESULTS: During 40,616.8 person-years of follow-up, 291 incident cases of CKD developed; 787 patients (7.4%) had metabolic syndrome at baseline and 1,444 (14.4%) developed incident metabolic syndrome during follow-up. After adjustment for age, baseline GFR, gamma-glutamyltransferase level, and uric acid level, metabolic syndrome at baseline was associated with a significantly increased risk of CKD (HR, 1.99; 95% confidence interval, 1.46 to 2.73). Metabolic syndrome over time as a time-dependent variable also predicted the development of CKD (HR, 1.83; [corrected] 95% confidence interval, 1.34 to 2.49) [corrected] The relationship between metabolic syndrome and incident CKD remained significant, even after further adjustment for the homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein level, current smoking, alcohol consumption, or regular exercise. In addition, there were graded relationships between number of metabolic syndrome traits or quintile of homeostasis model assessment of insulin resistance over time as a time-dependent variable and risk of CKD. Both increased triglyceride and low high-density lipoprotein cholesterol levels among metabolic syndrome traits were associated with significantly increased risk of CKD. These results were effectively unchanged, even after additional adjustment for incident hypertension and incident diabetes. LIMITATIONS: Estimated GFR was used instead of a directly measured GFR to define CKD. CONCLUSION: Metabolic syndrome is an independent risk factor for the development of CKD in Korean men without hypertension or diabetes, even with changes in status of metabolic syndrome over time.

Changes in body weight predict CKD in healthy men.

Several recent prospective studies have reported that obesity is associated with an increased risk for chronic kidney disease (CKD), but it is unknown whether weight gain increases the risk for CKD if one remains within the "normal" category of body mass index (BMI). We prospectively followed a cohort of 8792 healthy men who had no known risk factors for CKD and participated in a comprehensive health evaluation program at a large worksite. During 35,927 person-years of follow-up, 427 new incident cases of CKD (estimated GFR <64 ml/min per 1.73 m(2)) developed. Cox proportional hazards modeling revealed that in both the normal-weight and overweight groups, a U-shaped association between weight change categories and development of CKD was observed after adjustment for age, baseline GFR, baseline BMI, HDL, fasting blood glucose, uric acid, and exercise habits. The lowest risk for CKD was observed among those whose weight changed -0.25 to <0.25 kg/yr (P < 0.001 for quadratic term). Weight change as a time-dependent variable was significantly related to CKD incidence. These relationships remained significant even after further adjustment for Homeostasis Model Assessment of Insulin Resistance, high-sensitivity C-reactive protein, systolic BP, diastolic BP, metabolic syndrome, incident hypertension, or incident diabetes. In summary, increases in body weight are independently associated with an increased risk for CKD, even when the BMI remains within the normal range.

Relationship between daily coffee intake and suicidal ideation.

OBJECTIVE: Caffeine is the most widely-used psychoactive substance in the world. The present study investigates the relationship between caffeine intake and suicide risk according to gender. METHOD: Analysis of the Kangbuk Samsung Cohort Study (KSCS) data from 80,173 individuals was performed using Chi-square tests and t-tests to determine the relationships between psychosocial constructs and gender. The relationship between caffeine intake and suicidal ideation was analyzed by obtaining odds ratios with multivariate logistic regression in which depression and sleep problems were adjusted for age. RESULTS: In both men and women with suicidal ideation, the proportion of those who consume four or more cups of coffee per day was highest among the groups of various coffee intake levels. The results on the relationship between daily coffee intake and suicidal ideation revealed that suicide risk was high in both men and women who consume four or more cups of coffee a day. However, once the age, depression and sleep problems were adjusted for, suicide risk decreased in women of 1-4 cups of coffee intake per day, whereas no change was observed in men. CONCLUSION: Regardless of psychiatric problems such as depression or sleep problems, regular and moderate caffeine intake likely reduces suicide risk as well as depression in women.

Relationship between working hours and probability to take alopecia medicine among Korean male workers: a 4-year follow-up study.

BACKGROUND: Many studies have reported the negative effects of long working hours on various health problems. However, whether hair loss is associated with working hours has been rarely investigated so far. The main purpose of this study is to explore the relationship between long working hours and the development of alopecia among Korean male workers. METHODS: A total of 13,391 male workers not to take alopecia medicine in 2013 were followed up to see if they have alopecia medicine after 4 years, and that was used to confirm the alopecia development. Weekly working hours were categorized into three groups: reference working hours (RWH; < 40 hours/week), long working hours (LWH, 40-52 hours/week), and much longer working hours (MLWH; > 52 hours/week). Multiple logistic regression analyses were conducted to investigate the relationship between long working hours and the development of alopecia after adjusting age, marital status, education, monthly household income, smoking, and work schedule within strata of the covariates. RESULTS: Long working hours was significantly related to the development of alopecia. The adjusted odds ratios (ORs) for the development of alopecia were 1.57 (95% confidence interval [CI]: 1.21-2.05) for LWH group and 1.74 (95% CI: 1.23-2.47) for MLWH group relative to RWH group. CONCLUSIONS: Our findings suggest that unintentional development of alopecia is another potential health consequence of long working hours among Korean male workers. Preventive interventions to promote appropriate and reasonable working hours are required in our society.

The association between long working hours and marital status change: middle-aged and educated Korean in 2014-2015.

BACKGROUND: We investigated the association between long workhours and marital status change from married to divorced or separated status that might have bad health effects. METHODS: A total of 40,654 participants with married status in 2014 were followed up in 2015. Weekly workhours were categorized into four groups: ≤ 40, 41-52, 53-60, and > 60 hours per week. Univariate and multivariate logistic regression analyses were performed to determine the relationship between groups of workhours and marital status change after adjusting for age, total monthly household income, working type, and depression with sex stratification. RESULTS: The study populations consisted of 8,346 (20.5%) females and 32,308 (79.5%) males. Odd ratios (ORs) of marital status change for females working for more than 60 hours per week was 4.26 (95% confidence interval [CI]: 1.25-14.5), when working less than or equal to 40 hours per week was used as reference in the crude model. ORs of working more than 60 hours per week was 4.57 (95% CI: 1.02-20.5) in female workers when considering age, total household earning per month, working type of daytime, and depression in a dose-response manner. However, for male workers, long workhours were not significantly related to change of marriage status. CONCLUSIONS: Long workhours for more than 60 hours per week had significantly higher risk of divorce or separation in females, but not in males. Further follow-up studies are needed to evaluate long term effects of long workhours on divorce risk.

Comparison of work-related musculoskeletal symptoms between male cameramen and male office workers.

BACKGROUND: Previous studies have classified cameramen's job as physiologically heavy work and identified the risk factors of work-related musculoskeletal disorders (WRMDs) in cameramen. However, those studies limited their research subjects to cameramen. In this study, we compared the frequency and severity of WRMDs between cameramen and office workers. METHODS: A total of 293 subjects working in four broadcasting companies in Korea were recruited. A questionnaire survey was conducted for a month, starting in October 2016. The subjects were divided into cameramen and office workers according to their occupation. We compared the frequency and severity of WRMDs and ergonomic risk assessment results between the two groups. RESULTS: The high-risk WRMD group had a higher proportion of cameramen than office workers. Moreover, the high ergonomic risk group also had a higher proportion of cameramen than office workers for WRMDs in the upper extremities and waist+lower extremities. In the multivariable-adjusted model comparing cameramen and office workers, the odds ratio (OR) with 95% confidence interval (95% CI) for high-risk WRMDs was 3.50 (95% CI: 1.92-7.72) for the upper extremities and 3.18 (95% CI: 1.62-6.21) for the waist and the lower extremities. The ORs by body parts were 3.11 (95% CI: 1.28-7.57) for the neck, 3.90 (95% CI: 1.79-8.47) for the shoulders, and 4.23 (95% CI: 1.04-17.18) for the legs and feet. CONCLUSIONS: Our study suggests that cameramen are at high risk of WRMDs. Workplace improvements and management of the neck, shoulders, and lower extremities, which are susceptible to WRMDs, are necessary to prevent musculoskeletal disorders among cameramen.

Bidirectional Association between Nonalcoholic Fatty Liver Disease and Gallstone Disease: A Cohort Study.

Nonalcoholic fatty liver disease (NAFLD) and gallstone disease (GD) are often found to coexist but the sequential relationship of NAFLD and GD to each other remains controversial. We prospectively evaluated the bidirectional relationship of NAFLD with GD. A cohort study was performed on Korean adults who underwent a health checkup and were followed annually or biennially for a mean of 6.0 years. Fatty liver and gallstones were diagnosed by ultrasound. NAFLD was defined as hepatic steatosis on ultrasonography in the absence of excessive alcohol use or other identifiable causes. The NAFLD severity was determined by non-invasive fibrosis markers. Among 283,446 participants without either gallstones or cholecystectomy at baseline, 6440 participants developed gallstones. Among 219,641 participants without NAFLD at baseline, 49,301 participants developed NAFLD. The multivariable-adjusted hazard ratio (95% confidence interval) for incident gallstone comparing the NAFLD group vs. the non-NAFLD group was 1.26 (1.17⁻1.35). Increased non-invasive fibrosis markers of NAFLD were positively associated with an increased incidence of gallstones in a graded and dose-responsive manner (p-trend < 0.01). The multivariable-adjusted hazard ratios (95% confidence intervals) for incident NAFLD comparing gallstone and cholecystectomy to no GD were 1.14 (1.07⁻1.22) and 1.17 (1.03⁻1.33), respectively. This large-scale cohort study of young and middle-aged individuals demonstrated a bidirectional association between NAFLD and GD. NAFLD and its severity were independently associated with an increased incidence of gallstones, while GD and cholecystectomy were also associated with incident NAFLD. Our findings indicate that the conditions may affect each other, requiring further studies to elucidate the potential mechanisms underlying this association.

Incidence and risk factors for metabolic syndrome in Korean male workers, ages 30 to 39.

PURPOSE: There are few prospective data on the incidence of metabolic syndrome. The goals of this study were to define the incidence of and specific risk factors for metabolic syndrome (MetS) in Korean male workers 30 to 39 years of age. METHODS: A prospective cohort study was undertaken involving 4,779 male workers, 30 to 39 years of age, who did not take medication for dyslipidemia or have a history of any malignancy at study entry. Subjects were reexamined annually at a university hospital in Seoul, Korea, over a 3-year period between 2002 to August 2005. A modified National Cholesterol Education Program definition of MetS with body mass index was used instead of waist circumference. Cox proportional hazards models were used to calculate adjusted hazard ratios in separate models for MetS. RESULTS: At the end of the 3-year follow-up period, MetS developed in 708 individuals. The unadjusted incidence density of MetS was 70.5 (95% CI, 65.3 approximately 75.37), and the age-adjusted incidence density of MetS was 76.9 per 1,000 person-years (95% CI, 67.8 approximately 86.1). Among a variety of candidate risk factors, uric acid, weight change, gamma-glutamyltranspeptidase, and alanine aminotransferase were independent risk predictors for MetS. CONCLUSIONS: The high-incidence density of this MetS in Korea may be an indicator of future increases in diabetes and cardiovascular disease.

A case of generalized argyria presenting with muscle weakness.

BACKGROUND: Argyria is a rare irreversible cutaneous pigmentation disorder caused by prolonged exposure to silver. Herein, we report a case of generalized argyria that developed after chronic ingestion of soluble silver-nano particles and presented with muscle weakness. CASE PRESENTATION: A 74-year-old woman visited our emergency room, complaining of fever and mental deterioration. She was diagnosed with acute pyelonephritis and recovered after antibiotic therapy. At presentation, diffuse slate gray-bluish pigmented patches were noticed on her face and nails. Two months prior to visiting our hospital, she was diagnosed with inflammatory myopathy and given steroid therapy at another hospital. We performed a nerve conduction study that revealed polyneuropathy. In skin biopsies from pigmented areas of the forehead and nose, the histopathologic results showed brown-black granules in basement membranes of sweat gland epithelia, which are diagnostic findings of argyria. We reviewed pathology slides obtained from the left thigh muscles and found markedly degenerated myofibers with disorganization of myofibrils without inflammatory reactions, consistent with unspecified myopathy, rather than inflammatory myopathy. The patient was diagnosed with generalized argyria with polyneuropathy and myopathy and transferred to a rehabilitation institution after being tapered off of steroids. CONCLUSIONS: Clinicians should be aware of clinical manifestations of argyria and consider it in differential diagnosis when they examine patients who present with skin pigmentation and muscle weakness.

Comparison of sleep quality based on direction of shift rotation in electronics workers.

BACKGROUND: Previous studies have reported the effects of direction of shift rotation on sleep, however, the findings are inconsistent. In this study, we investigated sleep quality related to direction of shift rotation using large-scale data from shiftwork-specific health examinations of electronics workers. METHODS: This study included 4750 electronics workers working in a rotating 3-shift system who completed a medical examination for shift workers survey from January 1 to December 31, 2014, at a general hospital. The subjects were categorized into one of two groups according to direction of shift rotation. We compared sleep quality index between the subjects who worked in forward rotation and backward rotation systems. RESULTS: Backward rotation was positively associated with prevalence of poor sleep quality. In the multivariable-adjusted model, when comparing backward rotation to forward rotation, the odds ratio (OR) with 95 % confidence interval (95 % CI) for poor sleep quality was 1.95 (1.58-2.41). After stratifying by gender, the ORs (95 % CIs) for poor sleep quality in male and female was 1.92 (1.47-2.49) and 2.13 (1.47-3.08), respectively. In subgroup analyses, backward rotation was significantly associated with poor sleep quality in workers ≥30 years of age compared with workers <30 years of age (adjusted OR 2.60 vs. 1.89, respectively; P for interaction <0.001). CONCLUSIONS: Our study supports that a backward rotation system is associated with poor sleep quality. Forward rotation systems should be considered to reduce sleep problems.

Age at Menarche and Gallstone Disease in Middle-Aged Women.

The goal of this study was to explore the association between age at menarche and gallstone disease (GSD) in Korean women and to determine whether any of the observed associations were mediated by adult adiposity. A cross-sectional study was performed on 83 275 Korean women, aged 30 years or older, who underwent a health checkup examination between March 2011 and April 2013. Information regarding age at menarche was collected using standardized, self-administered questionnaires. Gallstone disease was defined as either having gallstones or having had a cholecystectomy based on ultrasound. Logistic regression models were used to evaluate the association between age at menarche and GSD. Of the 83 275 women evaluated in this study, 3341 had GSD. Age at menarche was negatively associated with the prevalence of GSD. In a multivariable-adjusted model adjusting for potential confounders including reproductive factors and body weight at age 20, the odds ratios (95% confidence intervals) for GSD comparing menarche at <12, 12, 14, 15, and 16 to 18 years to menarche at 13 years were 1.46 (1.23-1.75), 1.19 (1.04-1.35), 0.97 (0.87-1.09), 0.92 (0.82-1.03), and 0.89 (0.78-1.02), respectively (P for trend <.001). Adjusting for adult body mass index or percentage fat mass (%) partially reduced these associations; however, they remained statistically significant. Early menarche was associated with increasing prevalence of GSD in a large sample of middle-aged women. The findings of this study extend the range of adverse health outcomes associated with early menarche and suggest that obesity prevention strategies could be useful for reducing the risk of GSD in women who experience early menarche.