Nam Hoon Kim

@korea.ac.kr

Endocrinology, Internal Medicine
Korea University College of Medicine

RESEARCH INTERESTS

Diabetes, Obesity, Lipid metabolism

94

Scopus Publications

Scopus Publications

  • A Novel Anthropometric Parameter, Weight-Adjusted Waist Index Represents Sarcopenic Obesity in Newly Diagnosed Type 2 Diabetes Mellitus
    Min Jeong Park, Soon Young Hwang, Nam Hoon Kim, Sin Gon Kim, Kyung Mook Choi, Sei Hyun Baik, and Hye Jin Yoo

    Korean Society for the Study of Obesity
    Background As the metabolic significance of sarcopenic obesity (SO) is revealed, finding an appropriate index to detect SO is important, especially for type 2 diabetes mellitus (T2DM) patients with accompanying metabolic dysfunction. Methods Participants (n=515) from the Korea Guro Diabetes Program were included to compare how well waist circumference (WC), waist hip ratio (WHR), waist height ratio (WHtR), and the weight-adjusted waist index (WWI) predict SO in newly diagnosed T2DM patients. Sarcopenia was defined based on guidelines from the 2019 Asian Working Group for Sarcopenia as both low muscle mass (appendicular skeletal muscle [ASM]/height2 <7.0 kg/m2 for men, <5.4 kg/m2 for women) and strength (handgrip strength <28.0 kg for men, <18.0 kg for women) and/or reduced physical performance (gait speed <1.0 m/sec). Obesity was defined as a WC ≥90 cm in men and ≥85 cm in women. The WHR, WHtR, and WWI were calculated by dividing the WC by the hip circumference, height, and √ weight, respectively. Results The WC, WHR, and WHtR correlated positively with the fat and muscle mass represented by truncal fat amount (TFA) and ASM, whereas the WWI was proportional to the TFA and inversely related to ASM. Of the four indices, the WWI showed the highest area under the receiver operative characteristic curve for SO. The WWI also exhibited a positive correlation with albuminuria and the mean brachial-ankle pulse wave velocity, especially in patients aged ≥65 years. Conclusion The WWI is the preferable anthropometric index for predicting SO in T2DM patients, and it might be a proper index for predicting cardiometabolic risk factors in elderly people.

  • Linear association between radioactive iodine dose and second primary malignancy risk in thyroid cancer
    Kyeong Jin Kim, Kyoung Jin Kim, Jimi Choi, Nam Hoon Kim, and Sin Gon Kim

    Oxford University Press (OUP)
    Abstract Background We aimed to investigate whether the risk of second primary malignancy (SPM) in patients with thyroid cancer (TC) receiving radioactive iodine (RAI) therapy rises in a cumulative, dose-dependent manner compared with those not undergoing RAI. Methods Using the Korean National Health Insurance Service National Health Information Database (2002-2019), we investigated hazard ratios of SPM associated with RAI in TC. SPM was defined as a second primary malignancy diagnosed at least 1 year after TC diagnosis. Results Of 217 777 patients with TC (177 385 women and 40 392 men; mean [SD] age, 47.2 [11.6] years), 100 448 (46.1%) received RAI therapy. The median (IQR) follow-up duration was 7.7 (5.5-10.3) years, and the median (IQR) cumulative RAI dose was 3.7 (1.9-5.6) GBq. From 2004 to 2019, SPM incidence rates were 7.30 and 6.56 per 1000 person-years in the RAI and non-RAI groups, respectively, with an unadjusted hazard ratio of 1.09 (95% confidence interval = 1.05 to 1.13); this rate remained at 1.08 (95% confidence interval = 1.04 to 1.13) after adjustment for multiple clinical confounding factors. Notably, SPM risk increased significantly, from 3.7 GBq with full adjustments, and a strong linear association between cumulative RAI dose and SPM was observed in the restricted cubic spline analysis. Regarding cancer subtypes, myeloid leukemia and salivary gland, trachea, lung and bronchus, uterus, and prostate cancers were the most significantly elevated risks in patients who underwent RAI therapy. Conclusions This study identified that SPM risk increased linearly in a dose-dependent manner in patients with TC undergoing RAI therapy compared with those not undergoing RAI therapy.


  • Association of long-term hyperglycaemia and insulin resistance with brain atrophy and cognitive decline: A longitudinal cohort study
    Ji Hee Yu, Regina E. Y. Kim, So Young Park, Da Young Lee, Hyun Joo Cho, Nam Hoon Kim, Hye Jin Yoo, Ji A Seo, Sin Gon Kim, Kyung Mook Choi,et al.

    Wiley
    To investigate the longitudinal changes in brain volume and cognitive function associated with diabetes at midlife, and to examine whether long‐term hyperglycaemia, insulin resistance or secretory function is associated with brain atrophy and cognitive decline.

  • Weight-adjusted waist as an integrated index for fat, muscle and bone health in adults
    Kyoung Jin Kim, Serhim Son, Kyeong Jin Kim, Sin Gon Kim, and Nam Hoon Kim

    Wiley
    AbstractBackgroundUnhealthy body composition, including high fat mass, low muscle mass and low bone mass, is a critical health issue in adults. The weight‐adjusted waist index (WWI) estimates fat and muscle mass and may have implications for bone health. We examined its association with body composition outcomes in a large Korean adult cohort.MethodsThis study used data from the Korean National Health and Nutrition Examination Survey (2008–2011). WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). Dual‐energy X‐ray absorptiometry was used to measure bone mineral density (BMD), appendicular lean mass (ALM) and total body fat percentage. Unhealthy body composition was defined as combined presence of high fat mass, low bone mass and low muscle mass.ResultsA total of 5983 individuals (3034 men [50.7%] and 2949 women [49.3%]; mean age: 63.5 ± 8.7 years) were included. WWI was positively correlated with total body fat percentage (r = 0.478, P &lt; 0.001) and inversely with ALM/weight (r = −0.485, P &lt; 0.001) and BMD at the lumbar spine (r = −0.187, P &lt; 0.001), femoral neck (r = −0.269, P &lt; 0.001) and total hip (r = −0.255, P &lt; 0.001). Higher WWI quartiles correlated with lower BMD, T‐scores and ALM/weight, along with increased total body fat, evident in both genders and more pronounced in women, even after adjusting for confounders. This trend remained statistically significant across WWI quartiles for all analyses (P &lt; 0.001). Higher WWI quartiles were also significantly associated with higher odds of unhealthy body composition, with adjusted odds ratio in the highest WWI group of 18.08 (95% CI, 4.32–75.61) in men and 6.36 (95% CI, 3.65–11.07) in women. The optimal cutoff values of WWI for unhealthy body composition were 10.4 cm/√kg in men and 10.5 cm/√kg in women.ConclusionsIn community‐dwelling adults, high WWI values are associated with unfavourable body composition outcomes, indicating high fat mass, low muscle mass and low bone mass. WWI can potentially serve as an integrated index of body composition, underscoring the need for further research to validate its use in clinical settings.

  • Effect of a Wearable Device-Based Physical Activity Intervention in North Korean Refugees: Pilot Randomized Controlled Trial
    Ji Yoon Kim, Kyoung Jin Kim, Kyeong Jin Kim, Jimi Choi, Jinhee Seo, Jung-Been Lee, Jae Hyun Bae, Nam Hoon Kim, Hee Young Kim, Soo-Kyung Lee,et al.

    JMIR Publications Inc.
    Background Effective health interventions for North Korean refugees vulnerable to metabolic disorders are currently unelucidated. Objective This study aimed to evaluate the effects of digital health interventions in North Korean refugees using a wearable activity tracker (Fitbit device). Methods We conducted a prospective, randomized, open-label study on North Korean refugees aged 19-59 years between June 2020 and October 2021 with a 12-week follow-up period. The participants were randomly assigned to either an intervention group or a control group in a 1:1 ratio. The intervention group received individualized health counseling based on Fitbit data every 4 weeks, whereas the control group wore the Fitbit device but did not receive individualized counseling. The primary and secondary outcomes were the change in the mean daily step count and changes in the metabolic parameters, respectively. Results The trial was completed by 52 North Korean refugees, of whom 27 and 25 were in the intervention and control groups, respectively. The mean age was 43 (SD 10) years, and 41 (78.8%) participants were women. Most participants (44/52, 95.7%) had a low socioeconomic status. After the intervention, the daily step count in the intervention group increased, whereas that in the control group decreased. However, there were no significant differences between the 2 groups (+83 and –521 steps in the intervention and control groups, respectively; P=.500). The effects of the intervention were more prominent in the participants with a lower-than-average daily step count at baseline (&lt;11,667 steps/day). After the 12-week study period, 85.7% (12/14) and 46.7% (7/15) of the participants in the intervention and control groups, respectively, had an increased daily step count (P=.05). The intervention prevented the worsening of the metabolic parameters, including BMI, waist circumference, fasting blood glucose level, and glycated hemoglobin level, during the study period. Conclusions The wearable device–based physical activity intervention did not significantly increase the average daily step count in the North Korean refugees in this study. However, the intervention was effective among the North Korean refugees with a lower-than-average daily step count; therefore, a large-scale, long-term study of this intervention type in an underserved population is warranted. Trial Registration Clinical Research Information Service KCT0007999; https://cris.nih.go.kr/cris/search/detailSearch.do/23622

  • Sleep Duration and the Risk of Type 2 Diabetes: A Community-Based Cohort Study with a 16-Year Follow-up
    Da Young Lee, Inha Jung, So Young Park, Ji Hee Yu, Ji A Seo, Kyeong Jin Kim, Nam Hoon Kim, Hye Jin Yoo, Sin Gon Kim, Kyung Mook Choi,et al.

    Korean Endocrine Society
    Background: We aimed to investigate the moderating effects of obesity, age, and sex on the association between sleep duration and the development of diabetes in Asians.Methods: We analyzed data from a cohort of the Korean Genome and Epidemiology Study conducted from 2001 to 2020. After excluding shift workers and those with diabetes at baseline, 7,407 participants were stratified into three groups according to sleep duration: ≤5 hours/night, &gt;5 to 7 hours/night (reference), and &gt;7 hours/night. The Cox proportional hazards analyses were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident type 2 diabetes mellitus (T2DM). Subgroup analyses were performed according to obesity, age, and sex.Results: During 16 years of follow-up, 2,024 cases of T2DM were identified. Individuals who slept ≤5 h/night had a higher risk of incident diabetes than the reference group (HR, 1.17; 95% CI, 1.02 to 1.33). The subgroup analysis observed a valid interaction with sleep duration only for obesity. A higher risk of T2DM was observed in the ≤5 hours/night group in non-obese individuals, men, and those aged &lt;60 years, and in the &gt;7 hours/night group in obese individuals (HRs were 1.34 [95% CI, 1.11 to 1.61], 1.22 [95% CI, 1 to 1.49], and 1.18 [95% CI, 1.01 to 1.39], respectively).Conclusion: This study confirmed the effect of sleep deprivation on the risk of T2DM throughout the 16-year follow-up period. This impact was confined to non-obese or young individuals and men. We observed a significant interaction between sleep duration and obesity.

  • New Therapeutic Approaches to the Treatment of Dyslipidemia 1: ApoC-III and ANGPTL3
    Ji Yoon Kim and Nam Hoon Kim

    Korean Society of Lipidology and Atherosclerosis
    Low-density lipoprotein cholesterol (LDL-C)-lowering therapy that increases LDL receptor expression in several ways robustly reduces the risk of atherosclerotic cardiovascular disease (CVD). However, a substantial risk of CVD still remains after intensive LDL-C reduction, which requires new treatment modalities for dyslipidemia and cardiovascular risk management. Triglycerides (TGs) and triglyceride-rich lipoproteins (TRLs) have received attention as indicators of residual cardiovascular risk and as direct causal factors for atherosclerosis and CVDs. Advances in understanding TG and TRL metabolism and their association with clinically evident CVDs have led to the development of novel therapeutic targets, including apolipoprotein C-III (apoC-III) and angiopoietin-like protein 3 (ANGPTL3). Genetic association studies have indicated that both apoC-III and ANGPTL3 play a causal role in the development of atherosclerotic CVD. Both molecules contribute to lipid dysregulation and atherosclerosis primarily by inhibiting lipoprotein lipase; however, recent evidence has shown that novel pathways exist in relation to their lipid-modifying activities. Notably, recent progress in therapeutic approaches, such as monoclonal antibodies or antisense oligonucleotides, has led to several novel therapeutics targeting apoC-III and ANGPTL3. This review summarized the recent updates and discussions related to apoC-III and ANGPTL3 expression.

  • Optimal Low-Density Lipoprotein Cholesterol Level for Primary Prevention in Koreans with Type 2 Diabetes Mellitus
    Ji Yoon Kim and Nam Hoon Kim

    Korean Diabetes Association
    Corresponding author: Nam Hoon Kim https://orcid.org/0000-0002-9926-1344 Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine, 73 Inchon-ro, Seongbuk-gu, Seoul 02841, Korea E-mail: pourlife@korea.ac.kr Diabetes mellitus (DM) is one of the most important risk factors for cardiovascular disease (CVD) [1], requiring intensive strategies for cardiovascular risk management in affected patients. A linear relationship between low-density lipoprotein cholesterol (LDL-C) level and incident CVD has been observed in patients with DM, as well as in individuals without DM [2,3]. Lowering LDL-C levels with statin therapy is currently a mainstay of dyslipidemia management in people with DM [4-8]. Previous randomized controlled trials of statins such as the Collaborative Atorvastatin Diabetes Study (CARDS) have shown that use of statins reduced the risk of adverse cardiovascular events in patients with type 2 diabetes mellitus (T2DM) [9]. In the 2013 American College of Cardiology/ American Heart Association guidelines, individuals with DM aged 40 to 75 years are included in four statin benefit groups, in which the cardiovascular benefits of statins clearly exceed the possible harms [10]. However, the level to which LDL-C should be lowered remains controversial, largely due to the limited number of treatto-target trials for statin and nonstatin therapies. Nonetheless, the concept of “the lower, the better” for LDL-C level is widely accepted based on clinical trials of high-intensity statins [11,12], ezetimibe [13], and proprotein convertase subtilisin/ kexin 9 (PCSK9) inhibitors [14,15]. These trials demonstrated that an LDL-C level less than 70 mg/dL was achievable with intensive management, resulting in a lower incidence of adverse cardiovascular events than that with higher levels of LDL-C using lowto moderate-intensity statins. Accordingly, the 2023 American Diabetes Association guideline recommends using high-intensity statins to reduce LDL-C levels by ≥50% of the baseline and to <70 mg/dL in patients with DM aged 40 to 75 years at high cardiovascular risk [4]. Similarly, the 2021 European Society of Cardiology recommends LDL-C level less than 70 mg/dL for patients with T2DM [5]. However, there is little evidence whether the same LDL-C target could be applied to Asians or Koreans. Most randomized controlled trials of statin or nonstatin therapies included a small number and proportion of Asians. In addition, some differences in the response to statin therapy have been observed between Europeans and Asians [16,17]. In this issue of Diabetes & Metabolism Journal, Moon et al. [18] provided important evidence of appropriate LDL-C level for cardiovascular health in Korean patients with T2DM. This study evaluated the incidence of CVD according to LDL-C level, type of comorbidity, and number of cardiovascular risk factors in patients with T2DM. This retrospective cohort study was conducted using the Korean National Health Insurance Service database and included 248,002 patients with T2DM without CVD. As a result, the risk of incident CVD increased linearly from an LDL-C level ≥70 mg/dL in most patients with T2DM, regardless of the type of comorbidities. The appropriate target LDL-C level could be considered <70 mg/dL when comorbidities are present and <100 mg/dL when the duration of DM is less than 5 years or if hypertension is absent. If paEditorial

  • Relative contributions of statin intensity, achieved low-density lipoprotein cholesterol level, and statin therapy duration to cardiovascular risk reduction in patients with type 2 diabetes: population based cohort study
    Ji Yoon Kim, Jimi Choi, Sin Gon Kim, and Nam Hoon Kim

    Springer Science and Business Media LLC
    Abstract Background Current guidelines recommend life-long use of statin for patients with type 2 diabetes (T2D), however, a number of patients discontinue statin therapy in clinical practice. We aimed to estimate the optimal statin therapy including statin therapy duration, statin intensity, and low-density lipoprotein cholesterol (LDL-C) level among patients with T2D in a real-world setting. Methods From Korean National Health Insurance Service Cohort (2007–2015), 8937 patients with T2D (≥ 40 years of age) who received statin therapy for at least 90 days were included. Risk of major adverse cardiovascular event (MACE) including ischemic heart disease, ischemic stroke, and cardiovascular death was estimated according to statin intensity, achieved serum LDL-C level, and statin therapy duration, respectively. The relative contributions of these factors to MACE risk were quantified by calculating the proportion of log-likelihood explained by each factor. Results The hazard ratio (HR) of MACE was lower in patients receiving moderate- or high-intensity statins than in those receiving low-intensity statins (HR, 0.72; p = 0.027). Among patients who received moderate- or high-intensity statins, lower achieved LDL-C level was associated with lower cardiovascular risk. Notably, the longer the patients received statins, the lower was the risk of MACE; the HR of MACE was significantly reduced after at least 18 months (adjusted HR, 0.70; p = 0.009) as a reference to 3–6 months of therapy. The proportion of explainable log-likelihood for MACE was greatest for statin duration (2.55), followed by achieved LDL-C level (2.18), and statin intensity (0.95). Conclusions Statin therapy duration is as important as or more crucial than statin intensity or achieved LDL-C level for the reduction of cardiovascular risk in T2D patients. The concept of “longer is better” regarding statin therapy should be considered in clinical practice.

  • Implications of fasting plasma glucose variability on the risk of incident peripheral artery disease in a population without diabetes: a nationwide population-based cohort study
    Hye Soo Chung, Soon Young Hwang, Jung A. Kim, Eun Roh, Hye Jin Yoo, Sei Hyun Baik, Nan Hee Kim, Ji A. Seo, Sin Gon Kim, Nam Hoon Kim,et al.

    Springer Science and Business Media LLC
    Abstract Background Diabetes have been known as a traditional risk factor of developing peripheral artery disease (PAD). However, the study evaluating the impact of long-term glycemic variability on the risk of developing PAD is limited, especially in a general population without diabetes. Methods We included 152,931 individuals without diabetes from the Korean National Health Insurance Service–Health Screening Cohort. Fasting plasma glucose (FPG) variability was measured using coefficient variance (FPG-CV), standard deviation (FPG-SD), and variability independent of the mean (FPG-VIM). Results A total of 16,863 (11.0%) incident cases of PAD were identified during a median follow-up of 8.3 years. Kaplan–Meier curves showed a progressively increasing risk of PAD in the higher quartile group of FPG variability than in the lowest quartile group (log rank P &lt; 0.001). Multivariable Cox proportional hazard analysis showed the hazard ratio for PAD prevalence as 1.11 (95% CI 1.07–1.16, P &lt; 0.001) in the highest FPG-CV quartile than in the lowest FPG-CV quartile after adjusting for confounding variables, including mean FPG. Similar degree of association was shown in the FPG-SD and FPG-VIM. In sensitivity analysis, the association between FPG variability and the risk of developing PAD persisted even after the participants were excluded based on previously diagnosed diseases, including stroke, coronary artery disease, congestive heart failure, chronic kidney disease, or current smokers or drinkers. Subgroup analysis demonstrated that the effects of FPG variability on the risk of PAD were more powerful in subgroups of younger age, regular exercisers, and those with higher income. Conclusions Increased long-term glycemic variability may have a significant prognostic effect for incident PAD in individuals without diabetes. Graphical Abstract

  • Fasting Glucose Variability and the Risk of Dementia in Individuals with Diabetes: A Nationwide Cohort Study
    Da Young Lee, Jaeyoung Kim, Sanghyun Park, So Young Park, Ji Hee Yu, Ji A Seo, Nam Hoon Kim, Hye Jin Yoo, Sin Gon Kim, Kyung Mook Choi,et al.

    Korean Diabetes Association
    Background: We investigated whether fasting glucose (FG) variability could predict the risk of dementia.Methods: This cohort study analyzed data from Koreans with diabetes after at least three health examinations by the Korean National Health Insurance Corporation between 2005 and 2010, which included at least one examination between 2009 and 2010. A total of 769,554 individuals were included, excluding those aged &lt;40 years and those with dementia. FG variability was measured using the variability independent of the mean (FG-VIM). The incidence of dementia was defined by the International Classification of Diseases 10th Revision codes and prescription of anti-dementia medication and was subdivided into Alzheimer’s disease (AD) and vascular dementia (VD).Results: During the 6.9-year follow-up, 54,837, 41,032, and 6,892 cases of all-cause dementia, AD, and VD, respectively, were identified. Cox proportional regression analyses showed that as the FG-VIM quartile increased, the risk of dementia serially increased after adjustment for metabolic factors, income status, and diabetes-related characteristics, including the mean FG. Participants in FG-VIM quartile 4 showed a 18%, 19%, and 17% higher risk for all-cause dementia, AD, and VD, respectively, than those in quartile 1; this particularly included non-obese patients with a longer duration of diabetes, high FG levels, dyslipidemia, and those taking glucose-lowering medications. Conversely, the baseline FG status and dementia showed a U-shaped association.Conclusion: Increased FG variability over 5 years can predict the risk of dementia in individuals with diabetes in Korea. This finding was more pronounced in patients with less favorable metabolic profiles.

  • Night blood pressure variability, brain atrophy, and cognitive decline
    Ji Hee Yu, Regina E. Y. Kim, So Young Park, Da Young Lee, Hyun Joo Cho, Nam Hoon Kim, Hye Jin Yoo, Ji A Seo, Seong Hwan Kim, Sin Gon Kim,et al.

    Frontiers Media SA
    BackgroundAlthough blood pressure variability (BPV) has emerged as a novel risk factor for Alzheimer's disease, few studies have examined the effects of night BPV on brain structure and function. This study investigated the association of night BPV with brain atrophy and cognitive function changes.MethodsThe analysis included 1,398 participants with valid ambulatory blood pressure (BP) monitoring at baseline and both baseline and 4-year follow-up brain magnetic resonance images who were recruited from the Korean Genome and Epidemiology Study. Participants underwent a comprehensive neuropsychological test battery. BPV was derived from ambulatory BP monitoring and calculated as a standard deviation (SD) of 24-h and daytime and nighttime BP.ResultsDuring the median follow-up of 4.3 years, increased SD of night systolic or diastolic BP was an indicator of total brain volume reduction, while daytime BPV or night average BP was not associated with total brain volume changes. High SD of night systolic BP was associated with reduced gray matter (GM) volume, independent of average night BP, and use of antihypertensive drugs. It also was associated with a reduction of temporal GM volume, mostly driven by atrophy in the left entorhinal cortex and the right fusiform gyrus. In cognitive performance, high variability of night systolic BP was associated with a decrease in visual delayed recall memory and verbal fluency for the category.ConclusionIncreased night BPV, rather than night mean BP, was associated with reduced brain volume and cognitive decline. High night BPV could be an independent predictor for rapid brain aging in a middle-aged population.

  • Associations between Weight-Adjusted Waist Index and Abdominal Fat and Muscle Mass: Multi-Ethnic Study of Atherosclerosis
    Ji Yoon Kim, Jimi Choi, Chantal A. Vella, Michael H. Criqui, Matthew A. Allison, and Nam Hoon Kim

    Korean Diabetes Association
    Background: The weight-adjusted waist index (WWI) reflected body compositional changes with aging. This study was to investigate the association of WWI with abdominal fat and muscle mass in a diverse race/ethnic population.Methods: Computed tomography (CT) data from 1,946 participants for abdominal fat and muscle areas from the Multi-Ethnic Study of Atherosclerosis (785 Whites, 252 Asians, 406 African American, and 503 Hispanics) were used. Among them, 595 participants underwent repeated CT. The WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). The associations of WWI with abdominal fat and muscle measures were examined, and longitudinal changes in abdominal composition measures were compared.Results: In all race/ethnic groups, WWI was positively correlated with total abdominal fat area (TFA), subcutaneous fat area, and visceral fat area, but negatively correlated with total abdominal muscle area (TMA) and abdominal muscle radiodensity (&lt;i&gt;P&lt;/i&gt;&lt;0.001 for all). WWI showed a linear increase with aging regardless of race and there were no significant differences in the WWI distribution between Whites, Asians, and African Americans. In longitudinal analyses, over 38.6 months of follow-up, all abdominal fat measures increased but muscle measures decreased, along with increase in WWI. The more the WWI increased, the more the TFA increased and the more the TMA decreased.Conclusion: WWI showed positive associations with abdominal fat mass and negative associations with abdominal muscle mass, which likely reflects the abdominal compositional changes with aging in a multi-ethnic population.

  • Impact of urinary iodine concentration on blood glucose levels and blood pressure: a nationwide population-based study
    Eyun Song, Min Jeong Park, Jung A Kim, Eun Roh, Ji Hee Yu, Nam Hoon Kim, Hye Jin Yoo, Ji A Seo, Sin Gon Kim, Nan Hee Kim,et al.

    Springer Science and Business Media LLC

  • Renoprotective Mechanism of Sodium-Glucose Cotransporter 2 Inhibitors: Focusing on Renal Hemodynamics
    Nam Hoon Kim and Nan Hee Kim

    Korean Diabetes Association
    Diabetic kidney disease (DKD) is a prevalent renal complication of diabetes mellitus that ultimately develops into end-stage kidney disease (ESKD) when not managed appropriately. Substantial risk of ESKD remains even with intensive management of hyperglycemia and risk factors of DKD and timely use of renin-angiotensin-aldosterone inhibitors. Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce hyperglycemia primarily by inhibiting glucose and sodium reabsorption in the renal proximal tubule. Currently, their effects expand to prevent or delay cardiovascular and renal adverse events, even in those without diabetes. In dedicated renal outcome trials, SGLT2 inhibitors significantly reduced the risk of composite renal adverse events, including the development of ESKD or renal replacement therapy, which led to the positioning of SGLT2 inhibitors as the mainstay of chronic kidney disease management. Multiple mechanisms of action of SGLT2 inhibitors, including hemodynamic, metabolic, and anti-inflammatory effects, have been proposed. Restoration of tubuloglomerular feedback is a plausible explanation for the alteration in renal hemodynamics induced by SGLT2 inhibition and for the associated renal benefit. This review discusses the clinical rationale and mechanism related to the protection SGLT2 inhibitors exert on the kidney, focusing on renal hemodynamic effects.

  • Identification of Healthy and Unhealthy Lifestyles by a Wearable Activity Tracker in Type 2 Diabetes: A Machine Learning-Based Analysis
    Kyoung Jin Kim, Jung-Been Lee, Jimi Choi, Ju Yeon Seo, Ji Won Yeom, Chul-Hyun Cho, Jae Hyun Bae, Sin Gon Kim, Heon-Jeong Lee, and Nam Hoon Kim

    Korean Endocrine Society
    Lifestyle is a critical aspect of diabetes management. We aimed to define a healthy lifestyle using objectively measured parameters obtained from a wearable activity tracker (Fitbit) in patients with type 2 diabetes. This prospective observational study included 24 patients (mean age, 46.8 years) with type 2 diabetes. Expectation–maximization clustering analysis produced two groups: A (&lt;i&gt;n&lt;/i&gt;=9) and B (&lt;i&gt;n&lt;/i&gt;=15). Group A had a higher daily step count, lower resting heart rate, longer sleep duration, and lower mean time differences in going to sleep and waking up than group B. A Shapley additive explanation summary analysis indicated that sleep-related factors were key elements for clustering. The mean hemoglobin A1c level was 0.3 percentage points lower at the end of follow-up in group A than in group B. Factors related to regular sleep patterns could be possible determinants of lifestyle clustering in patients with type 2 diabetes.


  • Remission of type 2 diabetes after gastrectomy for gastric cancer: diabetes prediction score
    Yeongkeun Kwon, Jin-Won Kwon, Jane Ha, Dohyang Kim, Jaehyeong Cho, Soo Min Jeon, Shin-Hoo Park, Jinseub Hwang, Nam Hoon Kim, and Sungsoo Park

    Springer Science and Business Media LLC

  • Fasting glucose variability as a risk indicator for end‐stage kidney disease in patients with diabetes: A nationwide population‐based study
    Da Young Lee, Jaeyoung Kim, Sanghyun Park, So Young Park, Ji Hee Yu, Ji A. Seo, Nam Hoon Kim, Hye Jin Yoo, Sin Gon Kim, Kyung Mook Choi,et al.

    MDPI AG
    Given the fact that diabetes remains a leading cause of end-stage kidney disease (ESKD), multi-aspect approaches anticipating the risk for ESKD and timely correction are crucial. We investigated whether fasting glucose variability (FGV) could anticipate the development of ESKD and identify the population prone to the harmful effects of GV. We included 777,192 Koreans with diabetes who had undergone health examinations more than three times in 2005–2010. We evaluated the risk of the first diagnosis of ESKD until 2017, according to the quartile of variability independent of the mean (VIM) of FG using multivariate-adjusted Cox proportional hazards analyses. During the 8-year follow-up, a total of 7290 incidents of ESKD were found. Subjects in the FG VIM quartile 4 had a 27% higher risk for ESKD compared to quartile 1, with adjustment for cardiovascular risk factors and the characteristics of diabetes. This effect was more distinct in patients aged &lt; 65 years; those with a long duration of diabetes; the presence of hypertension or dyslipidemia; and prescribed angiotensin-converting enzyme inhibitors, metformin, sulfonylurea, α-glucosidase inhibitors, and insulin. In contrast, the relationship between baseline FG status and ESKD risk showed a U-shaped association. FGV is an independent risk factor for kidney failure regardless of FG.

  • Bone mineral density and osteoporosis risk in young adults with atopic dermatitis
    Sooyoung Kim, Jimi Choi, Moon Kyun Cho, Nam Hoon Kim, Sin Gon Kim, and Kyeong Jin Kim

    Springer Science and Business Media LLC
    AbstractAtopic dermatitis (AD) has been increasing worldwide over the past few decades. AD has been reported to be associated with an increased risk of osteoporosis and fractures in adult AD patients. The aim of this study was to investigate the bone mineral density (BMD) to evaluate osteoporosis risk in young adults with AD by sex. This was a case–control cohort study using a national dataset from the Korea National Health and Nutrition Examination Survey 2007–2009. We included young adult AD patients (men aged 19 ≤ and &lt; 50 years, premenopausal women aged 19 ≤ and &lt; 50 years) and 1:5 propensity score weighting controls by age, sex, body mass index (BMI), vitamin D level, and alcohol/smoking status. BMD was measured by double energy X-ray absorptiometry at the lumbar spine, femur neck, and total femur. The prevalence of low BMD, defined by a Z-score ≤  − 2.0, was compared between AD and without AD. We analyzed 311 (weighted n = 817,014) AD patients and 8,972 (weighted n = 20,880,643) controls. BMD at the lumbar spine was significantly lower in the male AD group than in the male control group (mean ± SE, 0.954 ± 0.016 vs. 0.989 ± 0.002, P = 0.03). The prevalence of low BMD (Z-score) did not significantly differ between AD and non-AD subjects in both men (3.8% vs. 2.7%, P = 0.56) and women (6.4% vs. 3.3%, P = 0.40). Among AD patients, early age at diagnosis of AD, longer duration of AD, lower BMI, rural residence (for men), less education, low vitamin D level, late menarche, and more pregnancies (for women) were associated with low BMD. In conclusion, low BMD did not occur more frequently in young adults with AD than in non-AD controls. However, early-onset/longer AD duration and lower BMI were associated with low BMD among young adult patients with AD.

  • Implication of thyroid function in periodontitis: a nationwide population-based study
    Eyun Song, Min Jeong Park, Jung A. Kim, Eun Roh, Ji Hee Yu, Nam Hoon Kim, Hye Jin Yoo, Ji A. Seo, Sin Gon Kim, Nan Hee Kim,et al.

    Springer Science and Business Media LLC
    AbstractPossible links between periodontitis and various cardiometabolic and autoimmune diseases have been advocated on the basis of chronic inflammation or oxidative stress. However, the association between periodontitis and thyroid dysfunction is under-researched. Participants without previous thyroid disease or ongoing thyroid-related medication were included from a nationwide population-level survey. Participants were categorized into tertiles of thyroid stimulating hormone (TSH) levels (first tertile &lt; 1.76 mIU/L; second tertile 1.76–2.83 mIU/L; third tertile &gt; 2.83 mIU/L), and periodontal condition was assessed using the Community Periodontal Index. Of the total of 5468 participants, 1423 had periodontitis (26%). A significant difference in the weighted prevalence of periodontitis according to TSH tertiles was observed, with the highest prevalence in the first tertile (26.5%) and the lowest prevalence in the third tertile (20.9%, p = 0.003). Subjects in the first TSH tertile had higher odds for periodontitis than those in the third tertile (OR 1.36, 95% CI 1.10–1.68; p for trend = 0.005) after adjusting for covariates. This association was consistent across subgroups and within sensitivity analyses among subjects without specific factors affecting thyroid function or diseases reported to be related to periodontitis. The present study demonstrated that low TSH levels were associated with significantly higher odds for periodontitis.

  • Sarcopenia is associated with decreased gray matter volume in the parietal lobe: a longitudinal cohort study
    Ji Hee Yu, Regina E. Y. Kim, Jin-Man Jung, So Young Park, Da Young Lee, Hyun Joo Cho, Nam Hoon Kim, Hye Jin Yoo, Ji A Seo, Sin Gon Kim,et al.

    Springer Science and Business Media LLC
    Abstract Background Substantial evidence supports an association between physical activity and cognitive function. However, the role of muscle mass and function in brain structural changes is not well known. This study investigated whether sarcopenia, defined as low muscle mass and strength, accelerates brain volume atrophy. Methods A total of 1284 participants with sarcopenic measurements and baseline and 4-year follow-up brain magnetic resonance images were recruited from the Korean Genome and Epidemiology Study. Muscle mass was represented as appendicular skeletal muscle mass divided by the body mass index. Muscle function was measured by handgrip strength. The low mass and strength groups were defined as being in the lowest quintile of each variable for one’s sex. Sarcopenia was defined as being in the lowest quintile for both muscle mass and handgrip strength. Results Of the 1284 participants, 12·6%, 10·8%, and 5·4% were classified as the low mass, low strength, and sarcopenia groups, respectively. The adjusted mean changes of gray matter (GM) volume during 4-year follow-up period were − 9·6 mL in the control group, whereas − 11·6 mL in the other three groups (P &lt; 0·001). The significantly greater atrophy in parietal GM was observed in the sarcopenia group compared with the control group. In a joint regression model, low muscle mass, but not muscle strength, was an independent factor associated with a decrease of GM volume. Conclusions Sarcopenia is associated with parietal GM volume atrophy, in a middle-aged population. Maintaining good levels of muscle mass could be important for brain health in later adulthood.

  • Association of the triglyceride and glucose index with low muscle mass: KNHANES 2008–2011
    Jung A. Kim, Soon Young Hwang, Ji Hee Yu, Eun Roh, So-hyeon Hong, You-Bin Lee, Nam Hoon Kim, Hye Jin Yoo, Ji A. Seo, Nan Hee Kim,et al.

    Springer Science and Business Media LLC
    AbstractThe triglyceride-glucose (TyG) index is a simple surrogate marker of insulin resistance. We evaluated the association of the TyG index with low muscle mass using a nationwide population-based representative data. This is a cross-sectional study that included 9477 participants aged ≥ 40 years from the Korea National Health and Nutrition Examination Survey between 2008 and 2011. The TyG index was calculated as ln[triglyceride (mg/dL) × fasting plasma glucose (mg/dL)/2]. Dual-energy X-ray absorptiometry was used to measure appendicular lean mass (ALM). Low muscle mass was defined an ALM/weight of 2 standard deviations (SD) below of young participants. The overall prevalence of low muscle mass was 4.7%. The prevalence of low muscle mass increased linearly with the quartiles of the TyG index, 2.5%, 4.2%, 5.6%, and 6.7% in Q1–Q4, respectively. The TyG index was negatively associated with ALM/weight both in men (r = − 0.302) and women (r = − 0.230). The odds ratio (OR) for low muscle mass was 2.08 in the highest quartile compared to the lowest quartile. High TyG index was associated with an increased risk of low muscle mass (OR for 1SD increase: 1.13). Increased TyG index was associated with the risk of low muscle mass independent of confounding factors.

  • Treatment Modality and Risk of Heart Failure in Patients With Long-Standing Graves’ Disease: A Nationwide Population-Based Cohort Study
    Eyun Song, Mina Kim, Sojeong Park, Min Jeong Park, Jung A. Kim, Eun Roh, Ji Hee Yu, Nam Hoon Kim, Ji A. Seo, Sin Gon Kim,et al.

    Frontiers Media SA
    BackgroundOptimal treatment for persistent Graves’ disease following 12–18 months of treatment with anti-thyroid drugs (ATDs) is unclear. Given the increased risk of cardiovascular morbidity and mortality with hyperthyroidism, assessing the risk of cardiovascular events associated with different treatment modalities after the conventional ATD course would be valuable in determining the appropriate next-line therapy.MethodsThis retrospective cohort study included data from the Korean National Health Insurance database of 16,882 patients with newly diagnosed hyperthyroidism who received primary ATD treatment for 24 months. Patients were categorized based on the treatment they received after receiving ATD for 24 months: continued ATD for at least 12 more months (ATD group), radioiodine ablation (RIA) with remission (RIA group 1), and RIA without remission (RIA group 2). The incidence and risk of heart failure (HF), the leading cause of cardiovascular mortality in hyperthyroidism, were compared between patients and age-and sex-matched controls.ResultsThere were 16,516 (97.8%) patients in the ATD group, 230 (1.4%) in RIA group 1, and 136 (0.8%) in RIA group 2. Compared to that of controls, a significant difference in the cumulative incidence of HF was observed according to second-line treatment modality after adjusting for covariates; the risk was highest in patients in RIA group 2, with a hazard ratio (HR) of 2.54 (95% confidence interval (CI) 1.60–4.03), followed by those in the ATD group, with an HR of 1.23 (95% CI 1.20–1.36). Patients in RIA group 1 were not at an increased risk of HF compared to their matched controls (HR 0.77; 95% CI 0.38–1.54). When patients in the ATD group were further classified by the duration of ATD treatment at one-year intervals, the risk of HF was higher in patients with longer ATD use (p for linear trend &amp;lt; 0.001).ConclusionsIn patients with long-standing hyperthyroidism treated with conventional duration of ATD therapy, the risk of HF was attenuated by RIA with remission of hyperthyroidism and increased as ATD was required for longer duration. To reduce the risk of HF, resolution of hyperthyroidism with RIA should be considered in patients with long-standing Graves’ disease.