Background There is a growing body of evidence that epigenetic changes including DNA methylation influence the risk of type 2 diabetes (T2D) and its microvascular complications. We conducted a methylome-wide association study (MWAS) to identify differentially methylated sites (DMSs) of T2D and diabetic kidney disease (DKD) in a Korean population. Methods We performed an MWAS in 232 participants with T2D and 197 non-diabetic controls with Illumina EPIC bead chip using peripheral blood leukocytes. T2D group was subdivided into 87 DKD cases and 80 non-DKD controls. Additional 819 individuals from two population-based cohorts were used to investigate the association of identified DMSs with quantitative metabolic phenotypes. Mendelian randomization (MR) approach was applied to evaluate the causal effect of metabolic phenotypes on identified DMSs. Results We identified eight DMSs (each at BMP8A, NBPF20, STX18, ZNF365, CPT1A, and TRIM37, and two at TXNIP) which were significantly associated with the risk of T2D (P < 9.0×10 -8), including three that were previously known (DMSs in TXNIP and CPT1A). We also identified three DMSs (in COMMD1, TMOD1, and FHOD1) associated with DKD. With our limited sample size, we were not able to observe a significant overlap between DMSs of T2D and DKD. DMSs in TXNIP and CTP1A were associated with fasting glucose and HbA1c. In MR analysis, fasting glucose was causally associated with DMS in CPT1A. Conclusions In an East Asian population, we identified eight DMSs, including five novel CpG loci, associated with T2D and three DMSs associated with DKD at methylome-wide statistical significance.

The purpose of this longitudinal follow-up study was to investigate the risk of ischemic stroke nationwide in patients with seropositive rheumatoid arthritis (RA) and controls who were matched in age and sex. Patient data were collected from the National Health Insurance Service (NHIS) Health Screening (HEALS) cohort. Using the International Classification of Diseases code M05 (seropositive RA), with a prescription of any disease-modifying anti-rheumatic drug (DMARD), RA was identified. A total of 2,765 patients and 13,825 control subjects were included in our study. The 12-year incidence of ischemic stroke in each group was calculated using the Kaplan–Meier method. The risk ratio of ischemic stroke was estimated using Cox proportional hazards regression. Sixty-four patients (2.31%) in the seropositive RA group and 512 (3.70%) in the control group experienced ischemic stroke (P < 0.001) during the follow-up period. The hazard ratio of ischemic stroke in the seropositive RA group was 1.32 (95% confidence interval (CI), 1.02–1.73) after adjusting for age and sex. The adjusted hazard ratio of ischemic stroke in the seropositive RA group was 1.40 (95% CI, 1.07–1.82) after adjusting for demographics and comorbid medical disorders. According to the subgroup analysis, the hazard ratios of ischemic stroke risks in the female and hypertensive subgroups were 1.44 (95% CI, 1.05–1.97) and 1.66 (95% CI, 1.16–2.38), respectively. In the non-diabetes and non-dyslipidemia subgroups, the corresponding hazard ratios of ischemic stroke were 1.47 (95% CI, 1.11–1.95) and 1.43 (95% CI, 1.07–1.91). Seropositive RA patients have an increased risk of ischemic stroke. In female, hypertension, non-diabetes, and non-dyslipidemia RA subgroups, even without the traditional risk factors for stroke (except for hypertension), increased the risk, which could be potentially attributed to RA.

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Objective : The goal of the following statewide age and gender-coordinated cohort study in Korea is to find out if there is a link between acute myocardial infarction (AMI) and Parkinson's disease (PD). Methods : Utilizing the National Health Insurance Sharing Service cohort, patient data were collected. Six thousand four hundred seventy-five individuals with PD were distinguished by utilizing the International Classification of Diseases 10 code G20 and have enrolled in the PD group. The number of participants decreased to 5259 after excluding 1039 patients who were hospitalized less than one time or who visited an outpatient clinic less than twice. Then, 26295 individuals were selected as part of the control group after case control matching was conducted through 1 : 5 age-and gender-coordinated matching. The Cox proportional hazard regression analysis and Kaplan-Meier method were utilized to analyze the likelihood of AMI in PD. Results : After controlling for age and gender, the hazard ratio of AMI in the PD group was 3.603 (95% confidence interval [CI], 2.837-4.577). After that, the following hazard ratio of AMI in the PD group was modified against for co-morbid medical disorders, resulting in 3.551 (95% CI, 2.795-4.511). According to a subgroup analysis, in males and females aged <65 and aged ≥65 and in the non-diabetes and diabetes, hypertension and non-hypertension, dyslipidemia and non-dyslipidemia subgroups, the AMI incidence rates were dramatically higher in the PD group compared to that of the control. Conclusion : Individuals with PD have a greater chance of AMI, according to this cross-national study.

BACKGROUND: Previous observational studies reported that a lower serum 25-hydroxyvitamin D [25(OH)D] concentration is associated with a higher burden of cerebral small vessel disease (cSVD). The causality of this association is uncertain, but it would be clinically important, given that 25(OH)D can be a target for intervention. We tried to examine the causal effect of 25(OH)D concentration on cSVD-related phenotypes using a Mendelian randomization approach. METHODS: Genetic instruments for each serum 25(OH)D concentration and cSVD-related phenotypes (lacunar stroke, white matter hyperintensity, cerebral microbleeds, and perivascular spaces) were derived from large-scale genome-wide association studies. We performed 2-sample Mendelian randomization analyses with multiple post hoc sensitivity analyses. A bidirectional Mendelian randomization approach was also used to explore the possibility of reverse causation. RESULTS: We failed to find any significant causal effect of 25(OH)D concentration on cSVD-related phenotypes (odds ratio [95% CI], 1.00 [0.87–1.16], 1.01 [0.96–1.07], 1.06 [0.85–1.33], 1.00 [0.97–1.03], 1.02 [0.99–1.04], 1.01 [0.99–1.04] for lacunar stroke, white matter hyperintensity, cerebral microbleeds, and white matter, basal ganglia, hippocampal perivascular spaces, respectively). These results were reproduced in the sensitivity analyses accounting for genetic pleiotropy. Conversely, when we examined the effects of cSVD phenotypes on 25(OH)D concentration, cerebral microbleeds were negatively associated with 25(OH)D concentration (0.94 [0.92–0.96]). CONCLUSIONS: Given the adequate statistical power (>0.8) of the analyses, our findings suggest that the previously reported association between 25(OH)D concentration and cSVD phenotypes might not be causal and partly attributed to reverse causation.

Objective: The purpose of this nationwide age-and sex-matched longitudinal study was to determine the pyogenic spondylitis (PS) increases the incidence of ischemic stroke (IS) in Korea.Methods: From the National Health Insurance Service (NHIS), we collected the patient data for the period from January 1, 2004 to December 31, 2015. PS was classified according to the International Classification of Disease codes M46.2-M46.8, M49.2, and M49.3. By using a 1:5 age-and sex-stratified matching, a total of 628 patients and 3140 control subjects were included in the study. The IS incidence rates in PS and control group was calculated by using the Kaplan-Meier method. The outcome of hazard ratio of IS was estimated by Cox proportional hazards regression analyses. This study did not exclude PS as a result of postoperative complications.Results: According to the study, 51 patients (8.12%) in the PS group and 201 patients (6.4%) in the control group experienced IS. The adjusted hazard ratio of IS in the PS group was 3.419 (95% CI: 2.473-4.729) after adjusting individual medical condition and demographics. Following the results of subgroup analysis, the risk ratio of IS was greater in most of the subgroup categories (male, female, age <65, age >65, non-diabetic, hypertensive, non-hypertensive, dyslipidemic and non-dyslipidemic subgroup). However, the risk of IS did not differ significantly in diabetic subgroup (95% CI: 0.953-4.360). Conclusions:The risk rate of IS increased in patient with pyogenic spondylitis.

Objective: The aim of this nationwide age- and sex- matched longitudinal follow up study is to determine the risk of Parkinson’s disease (PD) associated with ischemic stroke in Korea.Methods: Patient data were collected from the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS). PD was identified using the International Classification of Diseases (ICD) 10-CM code G 20. In total, 6,475 patients were enrolled in the PD group from the NHISS. After subtracting 1,039 patients who underwent hospitalization less than once or those who visited an outpatient clinic less than two times, 5,259 patients who were diagnosed after January 1, 2004 ultimately participated in this study. After case-control match was done through 1:5 age- and sex- stratified matching, 26,295 individuals were chosen as control. Kaplan-Meier method and Cox proportional hazard regression analysis were performed to evaluate the risk of ischemic stroke in PD.Results: The hazard ratio of ischemic stroke in the PD group was 3.848 (95% confidence interval (confidence interval [CI]): 3.14-4.70) after adjusting for age and sex. The adjusted hazard ratio of ischemic stroke in PD group was 3.885 (95% CI: 3.17-4.75) after adjusting for comorbidities. According to subgroup analysis, in male and female and non-diabetes and diabetes and non-hypertension and hypertension and dyslipidemia and non-dyslipidemia subgroups, ischemic stroke incidence rates were significantly higher in the PD group than those in the control group.Conclusions: This nationwide longitudinal study suggests an increased risk of ischemic stroke in PD patients.

This nationally matched longitudinal study aimed to investigate the relationship between acute myocardial infarction (AMI) and ossification of the posterior longitudinal ligament (OPLL) in Korea.