Association between thyroid hormone levels, body composition and insulin resistance in euthyroid subjects with normal thyroid ultrasound: The Kangbuk Samsung Health Study.

OBJECTIVE: Thyroid hormones play crucial roles in the control of energy homoeostasis and can influence body composition. In contrast, the changes in body composition might influence thyroid hormone levels. We evaluated associations between thyroid hormone levels, body composition and insulin resistance in euthyroid subjects with normal thyroid ultrasound (US) findings. DESIGN AND PATIENTS: This retrospective cross-sectional study included 36 655 euthyroid subjects who joined the medical health check-up programme at our institution. Serum thyroid hormone levels were analysed in association with body fat percentage (BFP), skeletal muscle mass index (SMI) and homoeostatic model assessment of insulin resistance (HOMA-IR). Linear regression analyses were performed to evaluate relationships between thyroid hormone levels and anthropometric parameters. RESULTS: Mean age was 36.4 years, and 49% of subjects were female. In multiple linear regression analysis, serum-free triiodothyronine (FT3) levels exhibited positive associations with waist circumference (WC) and HOMA-IR and a negative association with body weight, body mass index (BMI) and SMI among both men and women. The association between serum-free thyroxine (FT4) levels and anthropometric markers showed inconsistent results in men and women. Serum thyroid-stimulating hormone (TSH) levels showed a positive association with HOMA-IR in both men and women. CONCLUSIONS: Lower SMI was significantly associated with higher serum FT3 levels, the active form of thyroid hormone, in both men and women. Higher insulin resistance was positively associated with serum FT3 levels and inversely associated with serum TSH levels in euthyroid subjects with normal thyroid US findings.

Glucocorticoid-Induced Hyperglycemia: A Neglected Problem.

Glucocorticoids provide a potent therapeutic response and are widely used to treat a variety of diseases, including coronavirus disease 2019 (COVID-19) infection. However, the issue of glucocorticoid-induced hyperglycemia (GIH), which is observed in over one-third of patients treated with glucocorticoids, is often neglected. To improve the clinical course and prognosis of diseases that necessitate glucocorticoid therapy, proper management of GIH is essential. The key pathophysiology of GIH includes systemic insulin resistance, which exacerbates hepatic steatosis and visceral obesity, as well as proteolysis and lipolysis of muscle and adipose tissue, coupled with ß-cell dysfunction. For patients on glucocorticoid therapy, risk stratification should be conducted through a detailed baseline evaluation, and frequent glucose monitoring is recommended to detect the onset of GIH, particularly in high-risk individuals. Patients with confirmed GIH who require treatment should follow an insulin-centered regimen that varies depending on whether they are inpatients or outpatients, as well as the type and dosage of glucocorticoid used. The ideal strategy to maintain normoglycemia while preventing hypoglycemia is to combine basal-bolus insulin and correction doses with a continuous glucose monitoring system. This review focuses on the current understanding and latest evidence concerning GIH, incorporating insights gained from the COVID-19 pandemic.

Greater Severity of Steatosis Is Associated with a Higher Risk of Incident Diabetes: A Retrospective Longitudinal Study.

BACKGRUOUND: Fatty liver is associated with increased risk of developing type 2 diabetes. We aimed to evaluate whether the severity of hepatic steatosis is associated with incident diabetes. METHODS: We conducted a longitudinal analysis using data from 1,798 participants who underwent a comprehensive health checkup and abdominal computed tomography (CT). We assessed the association between baseline liver attenuation value on non-contrast CT images and risk of incident diabetes. All the participants were categorized into three groups based on the baseline liver attenuation value on non-contrast CT images: without hepatic steatosis (>57 Hounsfield unit [HU]), mild hepatic steatosis (41-57 HU), and moderate to severe hepatic steatosis (≤40 HU). RESULTS: During a median follow-up period of 5 years, 6.0% of the study participants progressed to diabetes. The incidence of diabetes was 17.3% in the moderate to severe hepatic steatosis group, 9.0% in the mild steatosis group, and 2.9% in those without hepatic steatosis. In a multivariate adjustment model, as compared with participants without hepatic steatosis, those with moderate to severe steatosis had a hazard ratio (HR) of 3.24 (95% confidence interval [CI], 1.64 to 4.2) for the development of diabetes, and those in the mild steatosis group had a HR of 2.33 (95% CI, 1.42 to 3.80). One standard deviation decrease in mean CT attenuation values of the liver was associated with a 40% increase in the development of diabetes (multivariate adjusted HR, 1.40; 95% CI, 1.2 to 1.63). CONCLUSION: We found a positive association between severity of hepatic steatosis and risk of incident diabetes. Greater severity of steatosis was associated with a higher risk of incident diabetes.

Dose-Dependent Effect of Smoking on Risk of Diabetes Remains after Smoking Cessation: A Nationwide Population-Based Cohort Study in Korea.

BACKGROUND: This study aimed to evaluate the dose-dependent effects of smoking on risk of diabetes among those quitting smoking. METHODS: We analyzed clinical data from a total of 5,198,792 individuals age 20 years or older who received health care check-up arranged by the national insurance program of Korea between 2009 and 2016 using the Korean National Health Insurance Service database. Cumulative smoking was estimated by pack-years. Smokers were classified into four categories according to the amount of smoking: light smokers (0.025 to 5 smoking pack-years), medium smokers (5 to 14 smoking pack-years), heavy smokers (14 to 26 smoking pack-years), and extreme smokers (more than 26 smoking pack-years). RESULTS: During the study period, 164,335 individuals (3.2% of the total population) developed diabetes. Compared to sustained smokers, the risk of diabetes was significantly reduced in both quitters (hazard ratio [HR], 0.858; 95% confidence interval [CI], 0.838 to 0.878) and nonsmokers (HR, 0.616; 95% CI, 0.606 to 0.625) after adjustment for multiple risk factors. The risk of diabetes gradually increased with amount of smoking in both quitters and current smokers. The risk of diabetes in heavy (HR, 1.119; 95% CI, 1.057 to 1.185) and extreme smokers (HR, 1.348; 95% CI, 1.275 to 1.425) among quitters was much higher compared to light smokers among current smokers. CONCLUSION: Smoking cessation was effective in reducing the risk of diabetes regardless of weight change. However, there was a potential dose-dependent association between smoking amount and the development of diabetes. Diabetes risk still remained in heavy and extreme smokers even after smoking cessation.

Protective effect of smoking cessation on subsequent myocardial infarction and ischemic stroke independent of weight gain: A nationwide cohort study.

Smoking cessation reduces the cardiovascular risk but increases body weight. We investigated the risk of subsequent myocardial infarction and ischemic stroke according to weight gain after smoking cessation, using a nationwide population based cohort. We enrolled 3,797,572 Korean adults aged over 40 years who participated in national health screenings between 2009 and 2010. Subjects who quit smoking were classified into three subgroups according to the weight change between baseline and 4 years prior. Myocardial infarctions and ischemic strokes were followed until the end of 2015. We compared the hazard ratios among smoking cessation subgroups, non-smokers, and current smokers. The mean changes in weight (1.5 ± 3.9 kg) of the smoking cessation group were higher than those of the other groups (p < 0.0001). A total of 31,277 and 46,811 subjects were newly diagnosed with myocardial infarction and ischemic stroke, respectively. Regardless of weight change, all subgroups of smoking cessation had significantly less risk than current smokers. The subgroup of smoking cessation with weight gain over 4kg showed the lowest risk for myocardial infarctions (hazard ratio 0.646, 95% confidence interval 0.583-0.714, p < 0.0001) and ischemic strokes (hazard ratio 0.648, 95% confidence interval 0.591-0.71, p < 0.0001) after multivariable adjustment. In conclusion, weight gain after smoking cessation did not adversely affect the cardiovascular protective effect.

Decreased Vagal Activity and Deviation in Sympathetic Activity Precedes Development of Diabetes.

OBJECTIVE: The objective of this study was to examine whether altered heart rate variability (HRV) could predict the risk of diabetes in Asians. RESEARCH DESIGN AND METHODS: A cohort study was conducted in 54,075 adults without diabetes who underwent 3-min HRV measurement during health checkups between 2011 and 2014 at Kangbuk Samsung Hospital. We analyzed the time domain (SD of the normal-to-normal interval [SDNN] and root mean square differences of successive normal-to-normal intervals [RMSSD]) and the frequency domain (total power, normalized low-frequency power [LF], and normalized high-frequency power [HF] and LF/HF ratio). We compared the risk of diabetes until 2017 according to tertiles of heart rate and HRV variables, with tertile 1 serving as the reference group. RESULTS: During 243,758.2 person-years, 1,369 subjects were diagnosed with diabetes. Both time and frequency domain variables were lower in the group with diabetes, with the exception of those with normalized LF and LF/HF ratio. In Cox analysis, as SDNN, RMSSD, and normalized HF tertiles increased, the risk of diabetes decreased (hazard ratios [95% CIs] of tertile 3: 0.81 [0.70-0.95], 0.76 [0.65-0.90], and 0.78 [0.67-0.91], respectively), whereas the risk of diabetes increased in the case of heart rate, normalized LF, and LF/HF ratio (hazard ratios [95% CIs] of tertile 3: 1.41 [1.21-1.65], 1.32 [1.13-1.53], and 1.31 [1.13-1.53), respectively) after adjusting for age, sex, BMI, smoking, drinking, systolic blood pressure, lipid level, CRP, and HOMA of insulin resistance. CONCLUSIONS: Abnormal HRV, especially decreased vagal activity and deviation in sympathovagal imbalance to sympathetic activity, might precede incident diabetes.

Relation between Baseline Height and New Diabetes Development: A Nationwide Population-Based Study.

BACKGROUND: Short stature and leg length are associated with risk of diabetes and obesity. However, it remains unclear whether this association is observed in Asians. We evaluated the association between short stature and increased risk for diabetes using the Korean National Health Screening (KNHS) dataset. METHODS: We assessed diabetes development in 2015 in 21,122,422 non-diabetic Koreans (mean age 43 years) enrolled in KNHS from 2009 to 2012 using International Classification of Diseases 10th (ICD-10) code and anti-diabetic medication prescription. Risk was measured in age- and sex-dependent quintile groups of baseline height (20 to 39, 40 to 59, ≥60 years). RESULTS: During median 5.6-year follow-up, 532,918 cases (2.5%) of diabetes occurred. The hazard ratio (HR) for diabetes development gradually increased from the 5th (reference) to 1st quintile group of baseline height after adjustment for confounding factors (1.000, 1.076 [1.067 to 1.085], 1.097 [1.088 to 1.107], 1.141 [1.132 to 1.151], 1.234 [1.224 to 1.244]), with similar results in analysis by sex. The HR per 5 cm height increase was lower than 1.00 only in those with fasting blood glucose (FBG) below 100 mg/dL (0.979 [0.975 to 0.983]), and in lean individuals (body mass index [BMI] 18.5 to 23 kg/m²: 0.993 [0.988 to 0.998]; BMI <18.5 kg/m²: 0.918 [0.9 to 0.935]). CONCLUSION: Height was inversely associated with diabetes risk in this nationwide study of Korean adults. This association did not differ by sex, and was significant in lean individuals and those with normal FBG levels.

Maintenance of body weight is an important determinant for the risk of ischemic stroke: A nationwide population-based cohort study.

BACKGROUND: Overweight is known as a risk factor for ischemic stroke. However, the effect of weight change on the development of ischemic stroke remains controversial. We investigated the relationship between weight change and the risk of ischemic stroke using a nationwide population-based cohort. METHODS: Our study enrolled 11,084,683 participants (Mean age 49.7±13.5 years, range 20-114 years) in the Korean National Health Screening Program from 2009 to 2012. Weight change was calculated using the difference between the baseline weight and the weight at health screening four years prior to the baseline. The occurrence of newly-diagnosed ischemic stroke was observed until the end of 2015. We categorized the study population according to weight change and performed multivariable analysis to compare the risk. RESULTS: Ischemic stroke was newly diagnosed in 113,591 subjects. The crude incidence rates of ischemic stroke per 1000 person-years according to the change in body weight were 3.059, 1.906, and 1.491 in the <-5%, ±5%, and ≥+5% groups, respectively. After adjusting all variables, the hazard ratio (HR) of ischemic stroke was higher in subjects who underwent weight loss (HR 1.152) or weight gain (HR 1.087) than in those who maintained their weight. When analyzed by eight groups of 5% intervals, the risk showed a U-shaped curve with those who maintained their weight showing the lowest risk. CONCLUSIONS: The risk of ischemic stroke was gradually increased in those who lost or gained more than 5% of their weight over four years, after adjusting for confounders. We should be aware of the increased risk of ischemic stroke in people who undergo weight change and should identify and manage the cause of weight change.

The Risk of Myocardial Infarction and Ischemic Stroke According to Waist Circumference in 21,749,261 Korean Adults: A Nationwide Population-Based Study.

BACKGROUND: Waist circumference (WC) is a well-known obesity index that predicts cardiovascular disease (CVD). We studied the relationship between baseline WC and development of incident myocardial infarction (MI) and ischemic stroke (IS) using a nationwide population-based cohort, and evaluated if its predictability is better than body mass index (BMI). METHODS: Our study included 21,749,261 Koreans over 20 years of age who underwent the Korean National Health Screening between 2009 and 2012. The occurrence of MI or IS was investigated until the end of 2015 using National Health Insurance Service data. RESULTS: A total of 127,289 and 181,637 subjects were newly diagnosed with MI and IS. The incidence rate and hazard ratio of MI and IS increased linearly as the WC level increased, regardless of adjustment for BMI. When the analyses were performed according to 11 groups of WC, the lowest risk of MI was found in subjects with WC of 70 to 74.9 and 65 to 69.9 cm in male and female, and the lowest risk of IS in subjects with WC of 65 to 69.9 and 60 to 64.9 cm in male and female, respectively. WC showed a better ability to predict CVD than BMI with smaller Akaike information criterion. The optimal WC cutoffs were 84/78 cm for male/female for predicting MI, and 85/78 cm for male/female for predicting IS. CONCLUSION: WC had a significant linear relationship with the risk of MI and IS and the risk began to increase from a WC that was lower than expected.

Prevalence and Annual Incidence of Thyroid Disease in Korea from 2006 to 2015: A Nationwide Population-Based Cohort Study.

BACKGROUND: The incidence of thyroid nodules has increased worldwide in recent years. Thyroid dysfunction is a potential risk factor for hypercholesterolemia, cardiovascular disease, osteoporosis, arrhythmia, and neuropsychiatric disease. This study investigated the prevalence and annual incidence of thyroid nodules, hypothyroidism, and hyperthyroidism in Koreans. METHODS: In this nationwide population-based cohort study, 51,834,660 subjects were included using the National Health Information database from 2006 to 2015, after the exclusion of subjects with thyroid cancer. RESULTS: The prevalence in Korea in 2015 of thyroid nodules, hypothyroidism in patients taking thyroid hormone, and hyperthyroidism in patients undergoing treatment was 15.82/1,000 population, 15.94/1,000 population, and 2.76/1,000 population, respectively. All these diseases were more prevalent among women than among men. The number of incident cases of these three thyroid diseases steadily increased from 2006 to 2012, and then decreased through 2015. The incidence of thyroid nodules, hypothyroidism treated with thyroid hormone, and treated hyperthyroidism was 6.79/1,000 population, 1.76/1,000 population, and 0.55/1,000 population, respectively, in Korea in 2015. The use of methimazole continuously increased, from 33% of total antithyroid drug prescriptions in 2006 to 74.4% in 2015, and it became the most frequently prescribed antithyroid drug in Korea. In contrast, the use of propylthiouracil continuously decreased. CONCLUSION: This was the first nationwide study of the prevalence and annual incidence of thyroid nodules, hypothyroidism, and hyperthyroidism to take into account recent changes and to include the current status of patients receiving treatment.

Increased risk of diabetes development in individuals with weight cycling over 4 years: The Kangbuk Samsung Health study.

AIMS: Weight cycling is defined as cyclical loss and gain of weight and recent studies suggest deleterious effects of weight cycling on cardiometabolic health. We aimed to analyze the risk for diabetes development in association with weight cycling over 4 years of follow-up. METHODS: A retrospective study performed in 4,818 non-diabetic participants (mean age 43 years, 78.3% men) in a health screening program in whom serial health examinations were performed in 5 consecutive years from 2010 to 2014. Average successive variability of weight (ASVW) was defined by the amount of body weight change in absolute value between the successive years over 5 years summed and divided by four. The subjects were divided into two groups according to body mass index (BMI), normal weight (<23 kg/m2) and overweight (≥23 kg/m2). RESULTS: Over 4 years, 3.2% developed diabetes. When the subjects were divided into 3 groups according to tertile groups of ASVW, those in the highest tertile showed significantly increased risk for diabetes development compared to those with the lowest tertile {odds ratio (OR) 1.860; 95% CI 1.130-3.063}. When similar analyses were performed according to the 4 groups divided by baseline body weight and ASVW over four years, those who were more than overweight at baseline with high ASVW showed significantly increased risk of diabetes development compared to those had normal weight and low ASVW (OR 2.266; 95% 1.123-4.572). When the subjects were divided into six group according to weight change and ASVW, those with increased weight over 4 years and high ASVW showed the highest risk for diabetes development among the groups compared to those with stable weight and low ASVW over four years (OR 3.660; 95% CI 1.402-9.553). CONCLUSIONS: Those with high ASVW showed significantly increased risk for diabetes development over four years compared with those who had low ASVW. Weight cycling was significantly associated with increased risk for diabetes.

Appropriate Amount of Regular Exercise Is Associated with a Reduced Mortality Risk.

PURPOSE: This study aimed at investigating whether there is a continuous dose-response relationship between the amount of physical activity (PA) and longevity benefit. METHODS: We evaluated the records of 23,257,723 Koreans age ≥20 yr who had undergone one biennial medical evaluation by the National Health Insurance Corporation. Participants with ≥20 min of vigorous or ≥30 min of moderate PA or walking were stratified into four groups: 0 d·wk; 1-3 d·wk; 4 to 5 d·wk; and 6-7 d·wk. After calculating total metabolic equivalent task-hours per week (MET·h·wk), we created eight categories of MET-hours per week (0, 0.1-4.9, 5.0-9.9, 10.0-14.9, 15.0-19.9, 20.0-24.9, 25.0-29.9, and ≥30.0). Multivariate Cox proportional hazard analyses were performed. RESULTS: A reverse J-shaped risk curve was observed, with the lowest mortality risk in the participants exercising 4 to 5 d·wk (reference). Participants who did not exercise at all and those who exercised with a PA frequency of 1 to 3 d·wk or 6 to 7 d·wk showed a significantly increased mortality risk compared with the reference group. When we repeated the Cox analysis among the 8 MET·h·wk categories with the participants reporting 20.0 to 24.9 MET·h·wk of PA as the reference group, we found that those with physical inactivity and 25.0-29.9 or ≥30.0 MET·h·wk of PA showed a higher mortality risk than the reference group. These relationships were persistently observed after adjustment for confounders. CONCLUSIONS: An appropriate amount of regular exercise in each specific type of PA was associated with the lowest risk of mortality. The inactive participants showed an increased mortality risk, and daily PA did not show any additional benefit in the mortality risk.

Pioglitazone Attenuates Palmitate-Induced Inflammation and Endoplasmic Reticulum Stress in Pancreatic ß-Cells.

BACKGROUND: The nuclear receptor peroxisome proliferator-activator gamma (PPARγ) is a useful therapeutic target for obesity and diabetes, but its role in protecting ß-cell function and viability is unclear. METHODS: To identify the potential functions of PPARγ in ß-cells, we treated mouse insulinoma 6 (MIN6) cells with the PPARγ agonist pioglitazone in conditions of lipotoxicity, endoplasmic reticulum (ER) stress, and inflammation. RESULTS: Palmitate-treated cells incubated with pioglitazone exhibited significant improvements in glucose-stimulated insulin secretion and the repression of apoptosis, as shown by decreased caspase-3 cleavage and poly (adenosine diphosphate [ADP]-ribose) polymerase activity. Pioglitazone also reversed the palmitate-induced expression of inflammatory cytokines (tumor necrosis factor α, interleukin 6 [IL-6], and IL-1ß) and ER stress markers (phosphor-eukaryotic translation initiation factor 2α, glucose-regulated protein 78 [GRP78], cleaved-activating transcription factor 6 [ATF6], and C/EBP homologous protein [CHOP]), and pioglitazone significantly attenuated inflammation and ER stress in lipopolysaccharide- or tunicamycin-treated MIN6 cells. The protective effect of pioglitazone was also tested in pancreatic islets from high-fat-fed KK-Ay mice administered 0.02% (wt/wt) pioglitazone or vehicle for 6 weeks. Pioglitazone remarkably reduced the expression of ATF6α, GRP78, and monocyte chemoattractant protein-1, prevented α-cell infiltration into the pancreatic islets, and upregulated glucose transporter 2 (Glut2) expression in ß-cells. Moreover, the preservation of ß-cells by pioglitazone was accompanied by a significant reduction of blood glucose levels. CONCLUSION: Altogether, these results support the proposal that PPARγ agonists not only suppress insulin resistance, but also prevent ß-cell impairment via protection against ER stress and inflammation. The activation of PPARγ might be a new therapeutic approach for improving ß-cell survival and insulin secretion in patients with diabetes mellitus.

Association between abdominal obesity and increased risk for the development of hypertension regardless of physical activity: A nationwide population-based study.

The presence of abdominal obesity and lack of physical activity are both risk factors for the development of hypertension. The aim of this study was to analyze the risk of developing hypertension according to baseline waist circumference (WC). In total, 16 312 476 non-hypertensive participants who were covered by the National Health Insurance Service (NHIS) from 2009 to 2012 in Korea were included in the study. The participants were divided into six groups according to the level of baseline WC with a 5-cm interval starting from 80 cm in men and 75 cm in women. The risk for the future development of hypertension was assessed in 2015 using the claims data on the diagnosis of hypertension and prescription of anti-hypertensive medications. Approximately 7.8% of the participants developed hypertension over a median follow-up of 5.48 years. The proportion of participants who developed hypertension significantly increased from 4.2% in the WC level 1% to 17.5% in the WC level 6. After adjusting for confounding factors, level 6 of the baseline WC had a higher hazard ratio (HR) for the development of hypertension among the 6 levels of baseline with level 3 as the reference (1736; 95% confidence interval [95% CI]: 1.72-1.753). The participants with abdominal obesity had a significantly higher HR than those without abdominal obesity regardless of whether they engage in high- or moderate-intensity physical intensity (1.741; 95% CI: 1.718-1.764). WC had a linear association with the development of hypertension based on this large nationwide population-based cohort study, which was not influenced by physical activity.

The persistence of fatty liver has a differential impact on the development of diabetes: The Kangbuk Samsung Health Study.

AIMS: To evaluate whether variable fatty liver status over time influence the risk of type 2 diabetes differently. METHODS: We analyzed the data from 7849 subjects without type 2 diabetes who underwent comprehensive health check-ups annually for 5 years. All subjects had an abdominal ultrasonography annually. The risk of incident diabetes was assessed in individuals with sustained non-alcoholic fatty liver disease (NAFLD), individuals with changed fatty liver status (intermittent NAFLD group), and individuals who did not have NAFLD (never NAFLD group) during the study period. A subgroup analysis was done in subjects of the intermittent NAFLD group. Incident diabetes was compared according to the number of time diagnosed as NAFLD by annual ultrasonography. RESULTS: During the mean follow-up of 4 years, subjects in the sustained NAFLD group had a HR of 1.50 (95% CI 1.13-1.98) for the development of diabetes compared with those in the never NAFLD group, whereas the risk was not higher in the intermittent NAFLD group (HR 0.99, 95% CI 0.76-1.31). When compared with the intermittent NAFLD group, multivariable adjusted HR for incident diabetes was 1.50 (95% CI 1.20-1.89) in the sustained NAFLD group. As the number of times diagnosed as NAFLD increased, the proportion of subjects who developed diabetes also increased (p = .002). CONCLUSIONS: The presence of fatty liver was differentially associated with incident diabetes based on its duration. The persistence of fatty liver status is an important factor for an independent association between NAFLD and incident diabetes.

The Association between Persistent Hypertriglyceridemia and the Risk of Diabetes Development: The Kangbuk Samsung Health Study.

BACKGROUND: Hypertriglyceridemia is known to have an association with increased risks of insulin resistance and diabetes. The aim of this study was to investigate the risk of diabetes mellitus, according to changes in the concentrations of triglycerides, over time. METHODS: A total of 15,932 non-diabetic participants (mean age 43.2 years, 68% men) who attended five consecutive annual health check-ups at Kangbuk Samsung Hospital, between January 2010 and December 2014, were recruited. Participants were classified according to their triglyceride concentrations; normal (<150 mg/dL) and abnormal (≥150 mg/dL). According to the triglyceride levels in 2010 and 2012, subjects were divided into four groups: normal-normal, normal-abnormal, abnormal-normal, and abnormal-abnormal. The risk for incident diabetes was assessed in 2014. RESULTS: Among the total subjects, 67.5% belonged to the normal-normal group, 8.6% to the normal-abnormal group, 9.4% to the abnormal-normal group, and 14.5% to the abnormal-abnormal group. A total of 234 subjects (1.5%) were newly diagnosed with diabetes, between 2010 and 2014. Over 4 years, 1%, 1.5%, 2.1%, and 3.0% of the subjects developed diabetes in the normal-normal, normal-abnormal, abnormal-normal, and abnormal-abnormal groups, respectively. When the risk for incident diabetes was analyzed in the groups, after adjusting the confounding variables, a 1.58-fold increase in the risk of diabetes (95% confidence interval [CI], 1.10 to 2.26) was observed in the participants with persistent hypertriglyceridemia (abnormal-abnormal group). This was attenuated by further adjustments for body mass index (BMI) (hazard ratio, 1.25; 95% CI, 0.86 to 1.80). CONCLUSION: In this large study population, persistent hypertriglyceridemia, over a period of 2 years, was significantly associated with the risk of incident diabetes, which was attenuated after adjustment for BMI.

Insulin resistance contributes more to the increased risk for diabetes development in subjects with low lipoprotein(a) level than insulin secretion.

BACKGROUND: Recent studies suggest an association between Lipoprotein(a) [Lp(a)] and the development of diabetes mellitus. We analyzed the association between baseline Lp(a) levels and diabetes development after 4 years of follow-up, in a population of apparently healthy Korean subjects. METHODS: A total of 2,536 non-diabetic participants (mean age: 41 years, men: 92%) of a health checkup program were included in the study. Diabetes development was defined by fasting blood glucose ≥126 mg/dL, HbA1c ≥6.5%, and self-reported treatment of diabetes. Homeostasis model assessment (HOMA) indices were used to assess insulin resistance (IR) and insulin secretion (IS). Presence of IR and impaired IS was defined by being in the highest quartile of HOMA-IR and in the lowest quartile HOMA-IS. RESULTS: After four years, 3.4% of the participants developed diabetes. The odds ratio (OR) of developing diabetes was lowest in the 4th quartile group of baseline Lp(a) (0.323 [95% CI 0.153-0.685])with the 1st quartile group as the reference. The subjects with both IR & impaired IS plus baseline Lp(a)<50 mg/dL showed the higher OR for diabetes development compared with those without IR and normal IS as the reference (67.277 [20.218-223.871], and those with IR plus Lp(a)<50 mg/dL showed higher OR for diabetes than in those with impaired IS and Lp(a)<50 mg/dL (3.811 [1.938-7.495] vs. 3.452 [1.620-7.353]). CONCLUSIONS: The subjects with low baseline Lp(a) level showed higher risk for development of diabetes compared with high baseline Lp(a) level, and this was prominent in those with IR than in those with impaired IS.

Association Between Coronary Artery Calcification and the Hemoglobin Glycation Index: The Kangbuk Samsung Health Study.

Context: The hemoglobin glycation index (HGI) is known to be correlated with the risk for cardiovascular disease. Objective: To analyze the association between incident coronary artery calcification (CAC) and the changes in HGI among participants without diabetes, over 4 years. Design, Setting, Participants, and Outcome Measures: A retrospective study of 2052 nondiabetic participants in whom the coronary artery calcium score was measured repeatedly over 4 years, as part of a health checkup program in Kangbuk Samsung Hospital in Korea, and who had no CAC at baseline. The HGI was defined as the difference between the measured and predicted hemoglobin A1c (HbA1c) levels. Results: A total of 201 participants developed CAC after 4 years, and the mean baseline HGI was significantly higher in those patients. The incidence of CAC gradually increased from the first to the fourth quartile groups of baseline HGI. The odds ratio (OR) for incident CAC was the highest among the four groups divided by the quartiles of the baseline HGI and was significant after adjustment for confounding variables (vs first quartile group: OR, 1.632; 95% confidence interval, 1.024 to 2.601). The incidence of and risk for CAC development were significantly higher than in other groups compared with the low-to-low group after adjustment for confounding factors; however, when baseline HbA1c level was included in the model, only participants with a low-to-high HGI over 4 years showed a significantly increased OR for CAC development compared with the low-to-low group (OR, 1.722; 95% confidence interval, 1.046 to 2.833). Conclusions: The participants with a high baseline HGI and consistently high HGI showed a higher risk for incident CAC than those with a low baseline HGI. An increased HGI over 4 years significantly increased the risk for CAC regardless of the baseline HbA1c levels.

Changes in Body Composition According to Age and Sex among Young Non-Diabetic Korean Adults: The Kangbuk Samsung Health Study.

BACKGROUND: Age-related decreases in lean mass represent a serious health problem. We aimed to analyze the risks of rapid decreases in lean mass by age and sex in relatively young Korean adults during a 4-year follow-up study. METHODS: A total of 65,856 non-diabetic participants (59.5% men, mean age 39.1 years) in a health screening program were subjected to bioimpedance body composition analyses and metabolic parameter analyses at baseline and after 4 years. The participants were sub-divided according to age, and additionally to six groups by age and the degree of body weight change over the 4-year period. The actual changes in body weight, lean mass, and fat mass and the percent changes over the 4-year period were assessed. RESULTS: The percent change in lean mass decreased and the percent change of fat mass increased with increasing age in every age and sex group. However, the annual percent decrease in lean mass and percent increase in fat mass were significantly higher among women than among men (-0.26% vs. -0.15% and 0.34% vs. 0.42%, respectively; P<0.01). Participants who were older than 50 years and had a weight loss <-5% during the 4 years had significantly greater decreases in lean mass and smaller decreases in fat mass, compared to those who were younger than 50 years. An odds ratio analysis to determine the lowest quartile of the percent change in lean mass according to age group revealed that participants older than 60 years had a significantly increased risk of a rapid decrease in the lean mass percentage (2.081; 95% confidence interval, 1.678 to 2.581). CONCLUSION: Even in this relatively young study population, the lean mass decreased significantly with age, and the risk of a rapid decrease in lean mass was higher among women than among men. Furthermore, the elderly exhibited a significantly more rapid decrease in lean mass, compared with younger participants.

A fluorescent immunosensor for high-sensitivity cardiac troponin I using a spatially-controlled polymeric, nano-scale tracer to prevent quenching.

For detection of high-sensitivity cardiac troponin I (hs-cTnI<0.01ng/mL), signal amplification was attained using a rapid immunosensor with a fluorescently-labeled, polymeric detection antibody. As fluorescent molecules tend to quench when they are less than 10nm apart, a synthetic scheme for the labeled antibody was devised to control the molecular distance and so minimize the quenching effect in a single conjugate unit. To this end, we first performed novel polymerization of fluorophore-coupled streptavidin (FL-SA) with biotinylated detection antibody (b-Ab) in a stepwise manner by adding FL-SA to b-Ab five times sequentially. Relative spatial positions of the fluorophore molecules in the polymer were then distally fixed using di-biotinylated oligonucleotides and passed through a 0.45µm filter to obtain a polymer of uniform size (i.e., ~400nm in diameter). We produced polymeric tracers using two different inexpensive fluorophores, Dylight 650 and Alexa 647, and applied it to the detection of hs-cTnI spiked in human serum using a two-dimensional chromatography-based immunosensor. The tracers showed a limit of detection of 0.002ng/mL for Dylight 650 and 0.007ng/mL for Alexa 647. The standard curves linearized via log-logit transformation exhibited regression lines with correlation coefficients (R(2))>0.97. The total coefficient of variation for the overall standard curve was 3.4±3.3% for the Dylight fluorophore and 5.9±1.5% for the Alexa dye. Such performances were comparable to those of the reference systems employing sophisticated technologies, Pathfast (Mitsubishi, Japan) and i-STAT (Abbott, US), with a strong correlation (R(2)>0.91) for the concentration range <100pg/mL.