Cancer Risk in Graves Disease with Radioactive 131I Treatment: A Nationwide Cohort Study.

Radioactive 131I (RAI) therapy has potential effects for the treatment of Graves disease (GD). However, whether RAI therapy for GD increases cancer risk remains controversial in medicine and public health. We aimed to investigate whether the risk of cancer increases in patients with GD receiving RAI therapy compared with those who did not. Methods: We used the Korean National Health Insurance Service's National Health Information Database from 2004 to 2020 and defined GD as prescribing antithyroid drugs, RAI, or thyroidectomy as a treatment for GD (International Classification of Diseases, 10th revision, E05 group). We investigated the hazard ratios (HRs) of overall and site-specific cancers associated with RAI in patients with GD. Subsequent cancer was defined as a primary malignancy treated at least 1 y after RAI therapy. Results: In total, 10,737 patients with GD who received RAI therapy (7,193 women, 67.0%; mean age, 43.7 ± 13.4 y) were matched to 53,003 patients with GD who had never received RAI treatment (35,471 women, 66.9%; mean age, 43.8 ± 13.2 y) in a 1:4-5 ratio by age, sex, and health checkup data. The median follow-up duration was 8.7 y (interquartile range, 5.2-12.1 y), and the median cumulative RAI dose was 555 MBq (interquartile range, 370-630 MBq) in the RAI therapy group. During 2004-2020, the overall subsequent cancer rates were 5.66 and 5.84 per 1,000 person-years in the RAI and non-RAI groups, respectively, with an unadjusted HR of 0.97 (95% CI, 0.88-1.06); this remained at 0.96 (95% CI, 0.83-1.10) after adjustment for multiple clinical confounding factors. For cancer subtypes, the risk of leukemia was significantly increased, with an HR of 2.39 (95% CI, 1.17-4.91). However, a loss of statistical significance was observed after adjusting for confounding factors, which may be attributed to the limited number of absolute events. Moreover, cancer-specific mortality was not different between the RAI and the non-RAI groups, with an adjusted HR of 0.99 (95% CI, 0.66-1.47). Conclusion: This study identified that the overall cancer risk in patients with GD who received RAI therapy compared with those who did not was not significant in Korea. Further long-term studies are needed to determine the risks and advantages of RAI therapy in patients with GD.

Increased Risk of Hip Fracture in Patients with Acromegaly: A Nationwide Cohort Study in Korea.

BACKGRUOUND: Acromegaly leads to various skeletal complications, and fragility fractures are emerging as a new concern in patients with acromegaly. Therefore, this study investigated the risk of fractures in Korean patients with acromegaly. METHODS: We used the Korean nationwide claims database from 2009 to 2019. A total of 931 patients with acromegaly who had never used an osteoporosis drug before and were treated with surgery alone were selected as study participants, and a 1:29 ratio of 26,999 age- and sex-matched osteoporosis drug-naïve controls without acromegaly were randomly selected from the database. RESULTS: The mean age was 46.2 years, and 50.0% were male. During a median follow-up of 54.1 months, there was no difference in the risks of all, vertebral, and non-vertebral fractures between the acromegaly and control groups. However, hip fracture risk was significantly higher (hazard ratio [HR], 2.73; 95% confidence interval [CI], 1.32 to 5.65), and non-hip and non-vertebral fractures risk was significantly lower (HR, 0.40; 95% CI, 0.17 to 0.98) in patients with acromegaly than in controls; these results remained robust even after adjustment for socioeconomic status and baseline comorbidities. Age, type 2 diabetes mellitus, cardio-cerebrovascular disease, fracture history, recent use of acid-suppressant medication, psychotropic medication, and opioids were risk factors for all fractures in patients with acromegaly (all P<0.05). CONCLUSION: Compared with controls, patients surgically treated for acromegaly had a higher risk of hip fractures. The risk factors for fracture in patients with acromegaly were consistent with widely accepted risk factors in the general population.

Elevated morbidity and mortality in patients with chronic idiopathic hypophosphatemia: a nationwide cohort study.

Background: Chronic idiopathic hypophosphatemia (CIH) induced by X-linked hypophosphatemic rickets or tumor-induced osteomalacia is a rare inherited or acquired disorder. However, due to its rarity, little is known about the epidemiology and natural course of CIH. Therefore, we aimed to identify the prevalence and long-term health outcomes of CIH patients. Methods: Using the Korean Health Insurance Review and Assessment claims database, we evaluated the incidence of hypophosphatemia initially diagnosed from 2003 to 2018. After excluding secondary conditions that could change serum phosphorus levels, we identified 154 patients (76 men and 78 women) with non-secondary and non-renal hypophosphatemia. These hypophosphatemic patients were compared at a ratio of 1:10 with age-, sex-, and index-year-matched controls (n = 1,540). Results: In the distribution of age at diagnosis, a large peak was observed in patients aged 1-4 years and small peaks were observed in ages from 40-70 years. The age-standardized incidence rate showed non-statistically significant trend from 0.24 per 1,000,000 persons in 2003 to 0.30 in 2018. Hypophosphatemic patients had a higher risk of any complication (adjusted hazard ratio [aHR], 2.17; 95% confidence interval [CI], 1.67-2.69) including cardiovascular outcomes, chronic kidney disease, hyperparathyroidism, osteoporotic fractures, periodontitis, and depression. Hypophosphatemic patients also had higher risks of mortality and hospitalization than the controls (aHR, 3.26; 95% CI, 1.83-5.81; and aHR, 2.49; 95% CI, 1.97-3.16, respectively). Conclusion: This first nationwide study of CIH in South Korea found a bimodal age distribution and no sex differences among patients. Hypophosphatemic patients had higher risks of complications, mortality, and hospitalization compared to age- and sex-matched controls.

Sex differences in mortality in patients with acromegaly: a nationwide cohort study in Korea.

OBJECTIVE: The results of previous studies on sex differences in mortality and comorbidities among patients with acromegaly are diverse. We assessed sex differences in mortality and the risk of complications in patients with acromegaly. METHODS: We included 1884 patients with acromegaly with 1:50 age- and sex-matched 94 200 controls using the Korean nationwide claims database from 2009 to 2019. RESULTS: During the median 5.51 years of follow-up, the acromegaly group had higher all-cause mortality than the control group (hazard ratio [HR] 1.74, 95% confidence interval [CI] 1.38-2.19), with higher risk in women than men (HR 2.17 vs 1.36). The most common cause of death was malignancy. Women with acromegaly aged ≥50 years exhibited significantly higher mortality than men with acromegaly aged ≥50 years (HR 1.74 vs 0.96). In a treatment subgroup other than surgery alone, women had a higher risk of mortality than men (HR 2.82 vs 1.58). Sex differences in mortality among patients with acromegaly remained equal after adjustment for the Charlson Comorbidity Index (CCI), socioeconomic status (SES), body mass index (BMI), alcohol consumption, smoking, fasting plasma glucose, creatinine, and total cholesterol. Patients with acromegaly had elevated risks of developing major adverse cardiovascular events (MACE), atrial fibrillation, obstructive sleep apnea (OSA), diabetes mellitus (DM), end-stage renal disease (ESRD), Parkinson's disease (PD), depression, and malignancy than age- and sex-matched controls, with a higher risk of OSA and DM in women than men. CONCLUSIONS: The risk of mortality and complications in patients with acromegaly compared to age- and sex-matched controls was higher in women than in men.

Weight-adjusted waist as an integrated index for fat, muscle and bone health in adults.

BACKGROUND: Unhealthy 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. METHODS: This 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. RESULTS: A 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 < 0.001) and inversely with ALM/weight (r = -0.485, P < 0.001) and BMD at the lumbar spine (r = -0.187, P < 0.001), femoral neck (r = -0.269, P < 0.001) and total hip (r = -0.255, P < 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 < 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. CONCLUSIONS: In 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.

All-cause and cause-specific mortality risks associated with calcium supplementation with or without vitamin D: A nationwide population-based study.

BACKGROUND: Current evidence regarding the mortality outcomes associated with calcium supplementation with or without low-dose vitamin D is conflicting. OBJECTIVES: To investigate the effects of calcium supplementation with or without vitamin D on all-cause and cause-specific mortalities in a large-scale cohort. METHODS: This study used data from the Korean National Health Insurance System database and National Death Registry. A total of 27,846 participants aged >55 years who had taken calcium supplements with or without vitamin D for at least 90 days (calcium supplementation only [CaO], n = 6256; calcium supplementation in combination with vitamin D [CaD], n = 21,590) were matched in a 1:1 ratio to those who did not take calcium or vitamin D supplements (control group) using propensity scores. RESULTS: No difference in all-cause mortality risk was found between the CaO and control groups: (adjusted hazard ratio [HR] = 1.00; 95% confidence interval [CI]: 0.92-1.10). However, all-cause mortality was lower in the CaD group (HR = 0.85; 95% CI: 0.80-0.89) compared with that in the control group. Mortality risk associated with cardiovascular disease (CVD) was decreased in the CaD group when the daily vitamin D dose received was less than 1000 IU (HR = 0.72; 95% CI: 0.64-0.81). Subgroup analysis showed significant effect of vitamin D with calcium in individuals who were female, aged ≥65 years or had previous history of cancer or CVD. CONCLUSION: In combination with calcium, vitamin D supplementation provides better outcomes for all-cause mortality, particularly CVD-associated mortality, in a duration-dependent manner.

Linear association between radioactive iodine dose and second primary malignancy risk in thyroid cancer.

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.

Bone mineral density and osteoporosis risk in young adults with atopic dermatitis.

Atopic 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 < 50 years, premenopausal women aged 19 ≤ and < 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.

Long Working Hours and Risk of Nonalcoholic Fatty Liver Disease: Korea National Health and Nutrition Examination Survey VII.

Background: The global incidence of NAFLD is rising sharply due to various risk factors. As previous studies reported adverse health impact of long working hours on metabolic diseases, such as diabetes mellitus and obesity, it is plausible that NAFLD is also associated with working excessive hours. However, data regarding this issue is limited. Methods: In this cross-sectional study based on Korea National Health and Nutrition Examination Survey VII, 5,661 working adults without previous liver disease or heavy alcohol drinking habits were included. The subjects were categorized into three groups according to working hours: 36-42, 43-52, and 53-83 hours/week. NAFLD was defined using the hepatic steatosis index (HSI), which is a validated prediction model for determining NAFLD. Results: The prevalence of NAFLD (HSI ≥36) increased with longer working hours: 23.0%, 25.6%, and 30.6% in the 36-42, 43-52, and 53-83 hours/week group, respectively (p <0.001). Subjects who worked 53-83 hours/week had higher odds for NAFLD than those who worked the standard 36-42 hours/week (OR 1.23, 95% CI 1.02-1.50, p = 0.033) after adjusting for age, sex, body mass index, smoking, alcohol, exercise, diabetes mellitus, hypertension, serum triglyceride, and total cholesterol. This association was consistent across subgroups according to working schedule (daytime vs. shift workers) or occupation type (office vs. manual workers). In particular, the relationship between long working hours and NAFLD was pronounced in workers aged <60 years and in female workers. Conclusions: Long working hours was significantly associated with NAFLD. Further prospective studies are required to validate this finding with causal relationship.

Effect of Metabolic Health and Obesity Phenotype on the Risk of Pancreatic Cancer: A Nationwide Population-Based Cohort Study.

BACKGROUND: Recently, a few studies have reported different results regarding the relationship between metabolic health and obesity phenotype and several cancers. We examined the effects of metabolic health and obesity phenotype on pancreatic cancer using a nationwide population-based cohort database. METHODS: Using the Korean National Health Insurance Service-Health Screening Cohort, we enrolled 347,434 Korean adults who underwent a health examination between 2009 and 2010 and were followed until 2015. This population was divided into four groups based on metabolically healthy status and body mass index (BMI): metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). RESULTS: Over a median follow-up of 6.1 (5.5-6.5) years, 886 individuals were diagnosed with pancreatic cancer. The adjusted HRs for incident pancreatic cancer were 1.52 [95% confidence interval (CI) 1.27-1.81] and 1.34 (95% CI, 1.12-1.61) for the MUNW and MUO phenotypes (compared with the MHNW phenotype) after adjusting for various confounding factors. However, compared with the MHNW phenotype, the MHO phenotype did not show an elevated risk of pancreatic cancer. Moreover, the HR for pancreatic cancer gradually increased with an increase in number of metabolically unhealthy components, even after adjusting for BMI (P trend < 0.001). CONCLUSIONS: Regardless of BMI, metabolically unhealthy phenotype demonstrated significantly increased risk of pancreatic cancer, whereas obese individuals with metabolically healthy phenotype did not. IMPACT: These findings suggest that metabolically unhealthy phenotype might represent a potential risk factor for pancreatic cancer occurrence independent of obesity.

Trends in Pediatric Thyroid Cancer Incidence, Treatment, and Clinical Course in Korea During 2004-2016: A Nationwide Population-Based Study.

Background: The incidence of thyroid cancer has increased worldwide. We investigated nationwide trends in the incidence and treatment course of pediatric thyroid cancer in South Korea. Methods: Using the National Health Information Database, we analyzed 1580 patients (324 males) <20 years of age diagnosed with thyroid cancer during 2004-2016 in South Korea. The annual percentage change (APC) in the age-standardized incidence rate (ASR) was calculated by joinpoint regression analysis. The initial treatment modality was categorized as either surgery only or surgery with radioactive-iodine treatment (surgery+RAIT), and we defined new treatment events as reoperations or additional RAITs among 1464 patients followed up for ≥12 months. Results: During 2004-2016, the mean ASR per 100,000 person-years increased from 0.6 [confidence interval; CI 0.5-0.8] to 0.9 [CI 0.8-1.1], with a mean APC of 4.0% [CI 1.8-6.2]. The ASRs (APCs) among 0-9-, 10-14-, 15-17-, and 18-19-year olds were 0.07 (9.9% [CI 0.08-20.7]), 0.6 (4.6% [CI 0.2-9.2]), 2.2 (3.9 [CI 1.7-6.0]), and 4.2 (3.5% [CI 0.9-6.2]), respectively. The lobectomy and lymph-node-dissection rates increased (from 18.5% to 33.6%, p = 0.0014; and from 29.6% to 84.5%, p < 0.001; respectively), but the RAIT rate decreased (67.9-39.7%, p < 0.001) during the study period. During a median 6.3-year follow-up, two patients died. New treatment events occurred in 56 (10.7%) of patients in the initial surgery-only group (n = 523). In the initial surgery+RAIT group (n = 941), 316 patients received two or more RAITs within 2 years, and 80 (12.8%) of the remaining 625 patients underwent new treatment events. In the surgery+RAIT subgroup, the event-free survival rate was lower in 0-14-year olds than in 18-19-year olds (hazard ratio 2.5 [CI 1.4-4.4]). Conclusions: The pediatric thyroid cancer incidence increased from 2004 to 2012 in South Korea. The lobectomy and lymph-node-dissection rates increased, but the RAIT rate decreased. The higher risk for new treatment events in patients younger than 15 years requiring initial RAIT may be linked to advanced stage at diagnosis, and it needs to be further evaluated.

Effects of radioactive iodine treatment on cardiovascular disease in thyroid cancer patients: a nationwide cohort study.

BACKGROUND: Radioactive iodine (RAI) treatment is a standard treatment in differentiated thyroid cancer (TC). However, its adverse effects on cardiovascular diseases (CVDs) have not been clearly elucidated. METHODS: In this retrospective cohort study based on the Korean National Health Insurance Service-National Health Screening Cohort (2002-2015), we analyzed 4,845 patients with TC with a median follow-up of 66 months. We evaluated and compared the risk of CVD between patients treated with and without RAI therapy. The primary CVD outcome was defined as a composite of ischemic stroke (IS), ischemic heart disease (IHD), hemorrhagic stroke (HS), or heart failure (HF). RESULTS: Overall, 2,533 patients (52.3%) received RAI treatment with a median cumulative dosage of 103 mCi [interquartile range (IQR), 40-162 mCi]. The incidence of the primary CVD outcome in patients who did not receive RAI therapy and those who did was 17.32 [95% confidence interval (CI), 15.07-19.90] and 13.96 (95% CI, 12.17-16.01) per 1,000 person-years, respectively, indicating an adjusted hazard ratio (HR) of 0.87 (95% CI, 0.71-1.07) after multivariate adjustments for variable confounding factors. The risks of IS (HR, 0.83; 95% CI, 0.51-1.34), IHD (HR, 0.90; 95% CI, 0.71-1.13), HS (HR 1.01; 95% CI, 0.49-2.09), and HF (HR 0.89; 95% CI, 0.49-1.63) were comparable between the patients who received RAI therapy and those who did not. There was no cumulative dose-dependent risk for CVD in TC patients who received RAI treatment. CONCLUSIONS: RAI treatment is a prevalent and crucial treatment for TC, and has been used in more than half of TC patients in Korea from 2004 to 2015. This study found no significant between-group difference for the CVD risk in patients with TC who received RAI treatment and those who did not, giving further evidence to allay concerns related to the adverse effects of RAI.

Trends in the Diagnosis and Treatment of Patients with Medullary Thyroid Carcinoma in Korea.

BACKGROUND: Thyroid cancer is becoming increasingly common worldwide, but little is known about the epidemiology of medullary thyroid carcinoma (MTC). This study investigated the current status of the incidence and treatment of MTC using Korean National Health Insurance Service (NHIS) data for the entire Korean population from 2004 to 2016. METHODS: This study included 1,790 MTC patients identified from the NHIS database. RESULTS: The age-standardized incidence rate showed a slightly decreasing or stationary trend during the period, from 0.25 per 100,000 persons in 2004 to 0.19 in 2016. The average proportion of MTC among all thyroid cancers was 0.5%. For initial surgical treatment, 65.4% of patients underwent total thyroidectomy. After surgery, external-beam radiation therapy (EBRT) was performed in 10% of patients, a proportion that increased from 6.7% in 2004 to 11.0% in 2016. Reoperations were performed in 2.7% of patients (n=49) at a median of 1.9 years of follow-up (interquartile range, 1.2 to 3.4). Since November 2015, 25 (1.4%) patients with MTC were prescribed vandetanib by December 2016. CONCLUSION: The incidence of MTC decreased slightly with time, and the proportion of patients who underwent total thyroidectomy was about 65%. EBRT, reoperation, and tyrosine kinase inhibitor therapy are additional treatments after initial surgery for advanced MTC in Korea.

Epidemiology and Prognosis of Pheochromocytoma/Paraganglioma in Korea: A Nationwide Study Based on the National Health Insurance Service.

BACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) are rare endocrine tumors originating from chromaffin cells. PPGLs are associated with a high mortality rate and several complications. To date, no epidemiological studies have been conducted on PPGLs in Asia. This study aimed to investigate the epidemiology and prognosis of PPGLs in Korea using nationwide data. METHODS: Using the National Health Insurance Service Database, subjects with a principal diagnosis of PPGLs on two or more occasions between 2003 and 2014 who satisfied the operational definition of PPGLs were included. Incidence, prevalence, complications, metastasis, and mortality were investigated. RESULTS: In total, 1048 subjects with a mean age of 47.6±16.1 years were included. There was no sex preponderance. The overall prevalence of PPGLs was 2.13 per 100,000 persons, and the overall age-standardized incidence rate was 0.18 per 100,000 person-years. Malignant PPGLs accounted for 17.7% (185 of 1,048) of cases, and 94 subjects exhibited metastasis at the time of diagnosis. Among initially non-metastatic PPGLs, 9.5% (nine of 954) eventually metastasized after a mean duration of 78.1±41.4 months. The 5-year survival rates for non-metastatic and metastatic PPGLs at diagnosis were 97% and 84%, respectively. Multivariable Cox regression models adjusted for covariates showed that metastatic PPGLs were associated with a 2.40-fold higher risk of mortality than non-metastatic PPGLs (95% confidence interval, 1.38 to 4.17; P=0.002). CONCLUSION: PPGLs are rare in Korea, and the prognosis of these endocrine tumors varies depending on whether they are benign or malignant. This epidemiological study paves the way for further research on PPGLs.

Comparison of anthropometric indices for the screening of nonalcoholic fatty liver disease in pre- and postmenopausal women.

OBJECTIVES: Although it has been well-established that menopause causes a shift in body fat, there has been no study conducted yet to examine the best obesity parameters to predict the risk of nonalcoholic fatty liver disease (NAFLD) in this population. Thus, the aim of this study was to clarify the superiority among various obesity indices such as body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) for predicting NAFLD in pre- and postmenopausal women. METHODS: This cross-sectional analysis included 620 healthy women (318 premenopausal and 302 postmenopausal women) between 20 and 80 years of age recruited from the Health Promotion Center of Korea University Guro Hospital. NAFLD was diagnosed by abdominal ultrasonography. RESULTS: In premenopausal women, there were no statistical differences in the area under the curve values among the three obesity indices, whereas, in postmenopausal women, the area under the curve value of WHR was significantly larger than those of either BMI (difference between area: 0.102, 95% confidence interval: 0.031, 0.173) or WC (difference between area: 0.064, 95% confidence interval: 0.018-0.109). Furthermore, in postmenopausal women, the combination of WHR with BMI or WC significantly increased predictive power of NAFLD when compared to using BMI or WC alone. The optimal cutoff values for BMI, WC, and WHR for detecting NAFLD were 23.9 kg/m, 69 cm, and 0.81 in premenopausal women and 22.9 kg/m, 74 cm, and 0.86 in postmenopausal women, respectively. CONCLUSIONS: In premenopausal women, BMI, WC, and WHR hold similar potential in predicting the risk of NAFLD, whereas, in postmenopausal women, WHR is the most useful discriminative indicator for NAFLD. Women's optimal cutoff values for NAFLD were different according to menopausal status.

Actual causes of death in thyroid cancer patients in Korea: A Nationwide Case Control Cohort Study.

OBJECTIVE: Thyroid cancer (TC) incidence has increased robustly in Korea. However, the actual cause of death, overall mortality risk, and cause-specific mortality risk in TC patients have not been clearly elucidated. DESIGN: Retrospective cohort study. METHODS: We analyzed 4082 TC patients from the Korean National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS, 2002-2013) with a median of 48-month follow-up. We compared these patients with 12 246 controls matched for age, sex, and histories of major cardiovascular disease (CVD) to investigate the cause of death and risks of overall and cause-specific mortality. RESULTS: Overall, 61 deaths (1.5%) occurred in the TC group. The most common cause of death was TC-specific mortality (32.8%), followed by other malignancy-related mortality (31.1%) and CVD mortality (13.1%). The overall mortality risk was comparable between the TC and control groups (unadjusted hazard ratio (HR): 1.17; 95% confidence interval (CI): 0.87-1.58); the adjusted HR remained at 1.25 (95% CI: 0.90-1.74) after multivariate adjustment for body mass index (BMI), socioeconomic status (SES), smoking, alcohol consumption, and histories of hypertension, diabetes mellitus, and dyslipidemia. In addition, there was not enough evidence against the surmise that the CVD mortality risk was similar between the TC and control groups, with an HR of 0.50 (95% CI: 0.22-1.16) after adjustment for CVD risk factors. CONCLUSIONS: Excellent overall survival was observed in TC patients. The most common cause of death was TC-specific mortality, suggesting the importance of thyroid cancer treatment. The overall and cause-specific mortality risks, particularly CVD mortality risk, did not differ between TC patients and the general population.

Incidence and Risk Factors for Dementia in Type 2 Diabetes Mellitus: A Nationwide Population-Based Study in Korea.

BACKGROUND: Diabetes mellitus is associated with an increased risk of dementia. We aimed to comprehensively analyze the incidence and risk factors for dementia and young-onset dementia (YOD) in diabetic patients in Korea using the National Health Insurance Service data. METHODS: Between January 1, 2009 and December 31, 2012, a total of 1,917,702 participants with diabetes were included and followed until the date of dementia diagnosis or until December 31, 2015. We evaluated the incidence and risk factors for all dementia, Alzheimer's disease (AD), and vascular dementia (VaD) by Cox proportional hazards analyses. We also compared the impact of risk factors on the occurrence of YOD and late-onset dementia (LOD). RESULTS: During an average of 5.1 years of follow-up, the incidence of all types of dementia, AD, or VaD was 9.5, 6.8, and 1.3/1,000 person-years, respectively, in participants with diabetes. YOD comprised 4.8% of all dementia occurrence, and the ratio of AD/VaD was 2.1 for YOD compared with 5.5 for LOD. Current smokers and subjects with lower income, plasma glucose levels, body mass index (BMI), and subjects with hypertension, dyslipidemia, vascular complications, depression, and insulin treatment developed dementia more frequently. Vascular risk factors such as smoking, hypertension, and previous cardiovascular diseases were more strongly associated with the development of VaD than AD. Low BMI and a history of stroke or depression had a stronger influence on the development of YOD than LOD. CONCLUSION: The optimal management of modifiable risk factors may be important for preventing dementia in subjects with diabetes mellitus.

Knockdown of Sestrin2 Increases Lipopolysaccharide-Induced Oxidative Stress, Apoptosis, and Fibrotic Reactions in H9c2 Cells and Heart Tissues of Mice via an AMPK-Dependent Mechanism.

Sestrin2 (sesn2) is an endogenous antioxidant protein that has recently gained attention for its potential to treat various inflammatory diseases. However, the relationship of sesn2 with cardiomyopathy is still unclear. In H9c2 cells, sesn2 knockdown reduced the level of 5' adenosine monophosphate-activated protein kinase (AMPK) phosphorylation, downregulated antioxidant genes including catalase and superoxide dismutase (SOD2), and increased reactive oxygen species (ROS) production upon lipopolysaccharide (LPS) treatment. LPS-mediated cell death and the expression of matrix metalloproteinase (MMP) 2 and MMP9 were significantly increased by sesn2 knockdown. However, these increases were prevented by treatment with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK activator. Consistent with the in vitro results, AMPK phosphorylation was decreased in heart tissue from sesn2 knockdown mice compared to heart tissue from control C57BL/6 mice, which was associated with decreased expression of antioxidant genes and increased LPS-mediated cell death signaling. Furthermore, the decrease in AMPK phosphorylation caused by sesn2 knockdown increased LPS-mediated expression of cardiac fibrotic factors, including collagen type I and type III, in addition to MMP2 and MMP9, in heart tissue from C57BL/6 mice. These results suggest that sesn2 is a novel potential therapeutic target for cardiomyopathy under inflammatory conditions.

The Status and Distinct Characteristics of Endocrine Diseases in North Korean Articles Published between 2006 and 2015.

BACKGROUND: Past decades of division have led to substantial differences in medical environments between South and North Korea. However, little is known about North Korea's medical status and research field, especially regarding endocrinology. In this study, we report the characteristics of North Korea's articles regarding endocrine-related diseases. METHODS: Among the nine medical journals, articles published in Internal Medicine between 2006 and 2015 were reviewed. A total of 2,092 articles were included; among them, 96 articles were associated with endocrinology. We analyzed these articles according to the disease categories they focused on and evaluated their features. RESULTS: Articles related to diabetes mellitus accounted for 55.2% (n=53) and those to thyroid disease accounted for 28.1% (n=27). Other disease categories, including adrenal gland (n=1), pituitary gland (n=1), and osteoporosis (n=3), comprised minor portions. Regarding diabetes mellitus, more than half the articles (n=33) focused on treatment and complications. Experimental studies were conducted with old hypoglycemic drugs or natural substances for the treatment of hyperglycemia. Regarding thyroid disease, articles related to hyperthyroidism were the most common (51.9%, n=14), followed by thyroid nodule/cancer (18.5%, n=5). Unique article features were short length, no figures, and less than five references. CONCLUSION: North Korea's endocrinology articles mainly focused on diabetes mellitus and thyroid disease. Persistent studies have been carried out in North Korea with dedication despite the poor medical environment. We hope that this study will be the beginning of mutual medical exchange and collaboration between North and South Korea.

Melatonin improves insulin resistance and hepatic steatosis through attenuation of alpha-2-HS-glycoprotein.

Melatonin plays an important role in regulating circadian rhythms. It also acts as a potent antioxidant and regulates glucose and lipid metabolism, although the exact action mechanism is not clear. The α2-HS-glycoprotein gene (AHSG) and its protein, fetuin-A (FETUA), are one of the hepatokines and are known to be associated with insulin resistance and type 2 diabetes. The aim of this study was to determine whether melatonin improves hepatic insulin resistance and hepatic steatosis in a FETUA-dependent manner. In HepG2 cells treated with 300 µmol/L of palmitic acid, phosphorylated AKT expression decreased, and FETUA expression increased, but this effect was inhibited by treatment with 10 µmol/L of melatonin. However, melatonin did not improve insulin resistance in FETUA-overexpressing cells, indicating that improvement in insulin resistance by melatonin was dependent on downregulation of FETUA. Moreover, melatonin decreased palmitic acid-induced ER stress markers, CHOP, Bip, ATF-6, XBP-1, ATF-4, and PERK. In addition, in the high-fat diet (HFD) mice, oral treatment with 100 mg/kg/day melatonin for 10 weeks reduced body weight gain to one-third of that of the HFD group and hepatic steatosis. Insulin sensitivity and glucose intolerance improved with the upregulation of muscle p-AKT protein expression. FETUA expression and ER stress markers in the liver and serum of HFD mice were decreased by melatonin treatment. In conclusion, melatonin can improve hepatic insulin resistance and hepatic steatosis through reduction in ER stress and the resultant AHSG expression.