Eunju Sung

Nonalcoholic fatty liver disease predicts chronic kidney disease in nonhypertensive and nondiabetic Korean men.

In the absence of significant research, we performed a prospective study to examine the association between nonalcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). The study cohort comprised a total of 8329 healthy men, with normal baseline kidney functions and no proteinuria, working in a semiconductor manufacturing company and its 13 affiliates. Alcohol intake was assessed with a self-reported questionnaire. Biochemical tests for liver and metabolic function and abdominal ultrasonography were done. Chronic kidney disease was defined as either the presence of proteinuria or a glomerular filtration rate (GFR) of <60 mL/min per 1.73 m(2). Cox proportional hazards model was used to estimate hazard ratios in the model for CKD. During 26717.1 person-years of follow-up, 324 men developed CKD. Nonalcoholic fatty liver disease was associated with the development of CKD (crude relative risk, 2.18; 95% confidence interval [CI], 1.75-2.71); and this relationship remained significant even after adjustment for age, GFR, triglyceride, and high-density lipoprotein cholesterol (adjusted relative risk [aRR], 1.55; 95% CI, 1.23-1.95). The association between NAFLD and incident CKD was evident in the NAFLD group with elevated serum gamma-glutamyltransferase (GGT) (aRR, 2.31; 95% CI, 1.53-3.50), even after adjustment for age, GFR, triglyceride, and high-density lipoprotein cholesterol, but not in the NAFLD group without elevated GGT (aRR, 1.09; 95% CI, 0.79-1.50) (P = .008 for interaction). To summarize, NAFLD with elevated GGT concentration was associated with an increased CKD risk among nondiabetic, nonhypertensive Korean men, irrespective of metabolic syndrome.

Weight gain within the normal weight range predicts ultrasonographically detected fatty liver in healthy Korean men

Objectives: We performed a prospective study to determine whether weight gain predicts future ultrasonographically detected fatty liver (USFL) in a lean adult population. Methods: Among 15 347 Korean male workers, aged 30–59 years, who participated in a health check-up programme in 2002, a USFL-free cohort of 4246 non-diabetic men was followed until September 2007. Alcohol consumption was assessed by a questionnaire. Weight change for each subject was calculated as the difference between baseline and subsequent measurements. Biochemical tests for liver and metabolic function were done. The primary outcome was ultrasound-diagnosed fatty liver. A standard Cox proportional hazards model and time-dependent Cox model were performed. Results: During 16 829.7 person-years of follow-up, 622 participants developed USFL. After adjusting for age, the period from visit 1 to visit 2, BMI, HDL-C, triglyceride, uric acid, alanine aminotransferase, and HOMA-IR, the risk for USFL increased with increasing quartiles of weight change (p for trend <0.001). This association remained significant when weight change and covariates, except age and the period from visit 1 to visit 2, were modelled as time-dependent variables. Subjects in the fourth quartile (weight gain ⩾2.3 kg) were at significantly elevated risk for USFL (adjusted hazard ratio (aHR), 1.26; 95% CI, 1.01 to 1.58). These associations did not change, even in normal weight men with a baseline BMI between 18.5 and 22.9 kg/m2 (n = 2186). Conclusion: Weight gain per se appears to increase the risk for developing USFL. Thus, avoiding weight gain, even among lean adult individuals, can be helpful in preventing this disease.

Relationship between insulin resistance and serum alanine aminotransferase as a surrogate of NAFLD (nonalcoholic fatty liver disease) in obese Korean children.

There has been increasing number of obese children who accompany obesity-related comorbidities. It has been known that nonalcoholic fatty liver disease (NAFLD) as one of obesity-related comorbidities is related with insulin resistance. So, we investigated the relation between insulin resistance and NAFLD, using serum alanine aminotransferase (ALT) as a surrogate of NAFLD among obese children in Korea. The study subjects were 909 obese children aged 9-12 years (boys 613, girls 296). Body mass index (BMI), waist circumference (WC), blood pressure, fasting blood glucose, fasting insulin, lipid profile were measured. ALT, liver enzyme was used as a surrogate of NAFLD and homeostasis model assessment of insulin resistance (HOMA-IR) was used as the index of insulin resistance. The prevalence of elevated serum ALT (>or=40 mg/dl) was 33.4% in boys, and 19.6% in girls respectively. In boys, ALT was correlated with BMI, waist circumference, total cholesterol, triglyceride, HDL-cholesterol, systolic and diastolic blood pressure, HOMA-IR, fasting serum insulin. Odds ratio for HOMA-IR against the elevated ALT (>or=40 mg/dl) was 1.061 (95% confidence interval, 1.020-1.103, P=0.003). In girls, ALT was correlated with BMI, waist circumference, total cholesterol, triglyceride, glucose, systolic and diastolic blood pressure, HOMA-IR, fasting serum insulin. Odds ratio for HOMA-IR against the elevated ALT (>or=40 mg/dl) was 1.042 (95% confidence interval, 0.998-1.088, P=0.063). Among obese Korean children, insulin resistance and ALT, lipid profile, BMI, WC, blood pressure showed significant correlation. Especially, in boys, higher ALT is founded to be independently associated with insulin resistance.

A1C and Coronary Artery Calcification in Nondiabetic Men and Women

Objective—This study aimed to examine the association between glycohemoglobin (A1C) and coronary artery calcification (CAC) in nondiabetic men and women without overt cardiovascular disease or diabetes mellitus after accounting for fasting glucose and traditional cardiovascular disease risk factors. Approach and Results—A cross-sectional study was performed in 25 564 Korean adults (41.4±7.0 years) with no diabetes mellitus (fasting glucose, ≥7.0 mmol/L or a history of diabetes mellitus) and no clinically evident cardiovascular disease, who underwent a health checkup, including a cardiac computed tomography estimation of CAC scores and measurements of cardiovascular risk factors. The presence of CAC was defined as a CAC score >0; CAC was observed in 12.0% of men and 4.9% of women. Age-adjusted odds ratios (95% confidence interval) for CAC comparing A1C of 5.5% to 5.6%, 5.7% to 5.9%, and 6.0% to 6.4% with A1C <5.5% were 1.12 (0.99–1.28), 1.44 (1.27–1.63), and 1.63 (1.39–1.90) in men and 1.76 (0.96–3.25), 1.86 (1.05–3.29), and 3.09 (1.68–5.70) in women, respectively. After adjusting for potential confounders, the odds ratios (95% confidence interval) comparing A1C of 5.5% to 5.6%, 5.7% to 5.9%, and 6.0% to 6.4% with A1C of <5.5% were 1.04 (0.91–1.19), 1.21 (1.07–1.38), and 1.25 (1.05–1.48) in men and 1.75 (0.94–3.29), 1.59 (0.88–2.87), and 2.48 (1.29–4.74) in women, respectively. These associations persisted in subjects without any metabolic abnormalities, including fasting glucose ≥100 mg/dL. Conclusions—A higher A1C level was found to have a modest and independent association with the subclinical coronary atherosclerosis, even in metabolically healthy individuals.

Obesity in Korean pre-adolescent school children: comparison of various anthropometric measurements based on bioelectrical impedance analysis

Objectives:To examine the relationships between body mass index (BMI), percentage-weight-for-height (PWH) and percentage body fat (PBF), and to compare their validity based on PBF with the BMI criteria of International Obesity Task Force (IOTF) for childhood obesity in Korean pre-adolescent school children.Design:Statistical comparative analysis for anthropometric measures.Subjects:Korean pre-adolescent children (438 boys and 454 girls, aged 8–12 years, mean BMI 19.5±3.4 kg/m2).Measurements:Body mass index and PWH were calculated as body size indices from height and weight. Hand-to-foot bioelectrical impedance analysis (BIA) was performed to obtain PBF values, with obese children defined as PBF above 35%. Sensitivity and specificity were displayed with the gold standard of PBF, and receiver operating characteristic (ROC) curves were used to assess the performance of BMI and PWH in detecting obesity.Results:The prevalence of obesity varied by the criteria: 18.8% by Korean BMI standards for 95 percentile, 11% by the IOTF-BMI 30 kg/m2 and 29.4% by Korean PWH cutoffs. Body mass index and PWH were significantly correlated with PBF after adjusting for age, 0.910 (P<0.01) and 0.915 (P<0.01), respectively. The sensitivity and specificity of the PWH cutoffs were 0.909 and 0.882, respectively. The local BMI 95 percentiles had lower sensitivity (0.714) and specificity (0.790). The IOTF-BMI definition showed much lower sensitivity (0.457) and higher specificity (0.990). The BMI cutoffs corresponding with the highest accuracy were smaller than IOTF-BMI 30 kg/m2 for all age groups in both boys and girls.Conclusion:The prevalence of obesity among Korean pre-adolescent children widely varied according to the diagnostic criteria applied. Universally recommended cutoffs for children by IOTF showed the lowest sensitivity among the criteria used, and may therefore underestimate obesity in this population.

Insulin Resistance is Associated with Gallstones Even in Non-obese, Non-diabetic Korean Men

It remains unclear as to whether insulin resistance alone or in the presence of well-known risk factors, such as diabetes or obesity, is associated with gallstones in men. The aim of this study was to determine whether insulin resistance is associated independently with gallstone disease in non-diabetic men, regardless of obesity. Study subjects were 19,503 Korean men, aged 30-69 yr, with fasting blood glucose level <126 mg/dL and without a documented history of diabetes. Gallbladder status was assessed via abdominal ultrasonography after overnight fast. Body mass index and waist circumference were measured. Insulin resistance was estimated by the Homeostasis Model Assessment of insulin resistance (HOMA-IR). The prevalence of obesity, abdominal obesity, and metabolic syndrome in the subjects with gallstones were higher than in those without. The prevalence of elevated HOMA (>75 percentile) in subjects with gallstones was significantly higher than in those without, and this association remained even after the obesity stratification was applied. In multiple logistic regression analyses, only age and HOMA proved to be independent predictors of gallstones. Insulin resistance was positively associated with gallstones in non-diabetic Korean men, and this occurred regardless of obesity. Gallstones appear to be a marker for insulin resistance, even in non-diabetic, non-obese men.

Abdominal obesity, systolic blood pressure, and microalbuminuria in normotensive and euglycemic Korean men.

Objectives:To evaluate the relationship between abdominal obesity and microalbuminuria (MA) in normotensive, euglycemic Korean men.Design:A cross-sectional study at a health screening center.Subjects:A total of 1321 healthy, normotensive Korean men, aged 20–78 years, with a fasting plasma glucose level <100 mg/dl.Measurements:Height, weight, and waist; systolic blood pressure (SBP); diastolic blood pressures (DBP); urinary albumin to creatinine ratio (ACR); fasting glucose, insulin, lipids, C-reactive protein (CRP), and white blood cell count. Waist circumference (WC) was used to indicate abdominal obesity and a single measurement of ACR was used to estimate MA. We also calculated body mass index (BMI) based on weight and height.Results:Mean BMI, WC, and SBP were significantly higher in subjects with MA than in those without (24.8±4.1 vs 23.8±2.7 kg/m2, 86±9 vs 83±8 cm, and 115±5 vs 112±7 mmHg, respectively). Multiple logistic regression analyses showed that only WC and SBP were independent predictors of MA.Conclusion:WC and SBP were positively associated with MA in normotensive and euglycemic Korean men.

Sleep Duration, Sleep Quality, and Markers of Subclinical Arterial Disease in Healthy Men and Women

Objective—Short and long sleep duration are associated with increased risk of clinical cardiovascular events, but the association between sleep duration and subclinical cardiovascular disease is not well established. We examined the association between sleep duration and sleep quality with coronary artery calcification (CAC) and with brachial–ankle pulse wave velocity (PWV) in a large sample of young and middle-aged asymptomatic adults. Approach and Results—We conducted a cross-sectional study of adult men and women who underwent a health checkup examination, including assessment of sleep duration and quality and coupled with either CAC (n=29 203) or brachial–ankle PWV (n=18 106). The multivariate-adjusted CAC score ratios (95% confidence interval) comparing sleep durations of ⩽5, 6, 8, and ≥9 hours with 7 hours of sleep were 1.50 (1.17–1.93), 1.34 (1.10–1.63), 1.37 (0.99–1.89), and 1.72 (0.90–3.28), respectively (P for quadratic trend=0.002). The corresponding average differences in brachial–ankle PWV were 6.7 (0.75–12.6), 2.9 (−1.7 to 7.4), 10.5 (4.5–16.5), and 9.6 (−0.7 to 19.8) cm/s, respectively (P for quadratic trend=0.019). Poor subjective sleep quality was associated with CAC in women but not in men, whereas the association between poor subjective sleep quality and brachial–ankle PWV was stronger in men than in women. Conclusions—In this large study of apparently healthy men and women, extreme sleep duration and poor subjective sleep quality were associated with increased prevalence of CAC and higher PWV. Our results underscore the importance of an adequate quantity and quality of sleep to maintain cardiovascular health.

Association of nephrolithiasis with metabolic syndrome and its components

OBJECTIVE Both metabolic syndrome (MetS) and nephrolithiasis (NL) are common and clinically important disorders. Therefore, we conducted this study to assess the association of MetS and NL. MATERIALS/METHODS Data were obtained from 116,536 individuals who underwent health screening tests between January 2010 and December 2010 at a health promotion center in Seoul, Korea. All subjects were asked to respond to a questionnaire including medical history of each subject. Anthropometric and biochemical measurements were applied to each subject. Presence of NL was evaluated by an abdominal ultrasonography. The subjects were classified into MetS and non-MetS group according to the criteria for MetS (National Cholesterol Education Program Adult Treatment Panel III). Compared to the non-MetS group, we estimated the Odds Ratios (ORs) and 95% Confidence Intervals (CIs) of the presence of NL in the MetS group adjusting for age, serum levels of creatinine and uric acid, and past medical history of NL based on the multivariate logistic regression analysis. RESULTS The prevalence of MetS was 15.9% (N=1129/7107) in the NL group, and 11.2% (N=12,287/109,429) in the non-NL group, respectively. After adjusting for the potential confounding factors, male MetS patients had a higher presence of NL than non-MetS subjects (OR 1.11; 95% CI 1.02-1.20; p=0.01). Of MetS components, only high blood pressure (BP) was a significantly related factor to the presence of NL (male; OR 1.08; 95% CI 1.01-1.15; p=0.043, female; OR 1.24; 95% CI 1.08-1.42; p=0.002). As the number MetS components increased, the presence of NL was significantly higher in male subjects (P for trend<0.001), but not in female subjects (P for trend=0.961). CONCLUSIONS We found that NL was associated with MetS and high BP.

Dietary sodium and potassium intake in relation to non-alcoholic fatty liver disease.

A few epidemiological data are available assessing the associations of intakes of sodium (Na) and potassium (K) with non-alcoholic fatty liver disease (NAFLD). We aimed to examine the associations of dietary intake of Na and K with the prevalence of ultrasound-diagnosed NAFLD. We performed a cross-sectional study of 100 177 participants (46 596 men and 53 581 women) who underwent a health screening examination and completed a FFQ at the Kangbuk Samsung Hospital Total Healthcare Centers, South Korea, between 2011 and 2013. NAFLD was defined by ultrasonographic detection of fatty liver in the absence of excessive alcohol intake or other known causes of liver disease. The proportion of NAFLD was 35·6 % for men and 9·8 % for women. Increasing prevalence of NAFLD was observed with increasing Na intake. The multivariable-adjusted prevalence ratios (PR) of NAFLD comparing the highest with the lowest quintile of energy-adjusted Na intake were 1·25 (95 % CI 1·18, 1·32; P trend<0·001) in men and 1·32 (95 % CI 1·18, 1·47; P trend <0·001) in women. However, when we additionally adjusted for body fat percentage, the association became attenuated; the corresponding PR of NAFLD were 1·15 (95 % CI 1·09, 1·21) in men and 1·06 (95 % CI 0·95, 1·17) in women. No inverse association was observed for energy-adjusted K intake. Our findings suggest that higher Na intake is associated with a greater prevalence of NAFLD in young and middle-aged asymptomatic adults, which might be partly mediated by adiposity.