Health Insurance Service-National Sample Cohort Research Articles

Long-term exposure to PM2.5 and mortality in a national cohort in South Korea: effect modification by community deprivation, medical infrastructure, and greenness

BackgroundLong-term exposure to PM2.5 has been linked to increased mortality risk. However, limited studies have examined the potential modifying effect of community-level characteristics on this association, particularly in Asian contexts. This study aimed to estimate the effects of long-term exposure to PM2.5 on mortality in South Korea and to examine whether community-level deprivation, medical infrastructure, and greenness modify these associations.MethodsWe conducted a nationwide cohort study using the National Health Insurance Service-National Sample Cohort. A total of 394,701 participants aged 30 years or older in 2006 were followed until 2019. Based on modelled PM2.5 concentrations, 1 to 3-year and 5-year moving averages of PM2.5 concentrations were assigned to each participant at the district level. Time-varying Cox proportional-hazards models were used to estimate the association between PM2.5 and non-accidental, circulatory, and respiratory mortality. We further conducted stratified analysis by community-level deprivation index, medical index, and normalized difference vegetation index to represent greenness.ResultsPM2.5 exposure, based on 5-year moving averages, was positively associated with non-accidental (Hazard ratio, HR: 1.10, 95% Confidence Interval, CI: 1.01, 1.20, per 10 µg/m3 increase) and circulatory mortality (HR: 1.22, 95% CI: 1.01, 1.47). The 1-year moving average of PM2.5 was associated with respiratory mortality (HR: 1.33, 95% CI: 1.05, 1.67). We observed higher associations between PM2.5 and mortality in communities with higher deprivation and limited medical infrastructure. Communities with higher greenness showed lower risk for circulatory mortality but higher risk for respiratory mortality in association with PM2.5.ConclusionsOur study found mortality effects of long-term PM2.5 exposure and underlined the role of community-level factors in modifying these association. These findings highlight the importance of considering socio-environmental contexts in the design of air quality policies to reduce health disparities and enhance overall public health outcomes.

Appendectomy and the Risk of Parkinson's Disease: A Korean Nationwide Study.

The vermiform appendix is considered a potential reservoir for the abnormal α-synuclein aggregate in Parkinson's disease (PD). Previous epidemiologic evidence on the association between appendectomy and PD risk remains inconclusive, especially outside the Western world. To investigate the association between appendectomy and PD risk in Korea. Among 703,831 eligible adult subjects in the National Health Insurance Service sample cohort, we identified 16,122 patients who underwent appendectomy. The rest formed the control group. PD risk was assessed using time-dependent Cox regression analyses. The appendectomy group did not have altered risk of PD compared with the control group in either unadjusted [hazard ratio (HR) 1.32, 95% confidence interval (CI) 0.97-1.80, P = 0.08] or adjusted model (HR 1.42, CI 0.88-2.30, P = 0.15). No further statistical difference appeared when stratified by sex. Appendectomy is not associated with altered risk of PD in the Korean population.

Risk Factors and Temporal Patterns of Poststroke Epilepsy across Stroke Subtypes: Insights from a Nationwide Cohort Study in Korea.

We aimed to investigate the risk factors associated with poststroke epilepsy (PSE) among patients with different subtypes of stroke, focusing on age-related risk and time-varying effects of stroke subtypes on PSE development. A retrospective, nationwide, population-based cohort study was conducted using Korean National Health Insurance Service-National Sample Cohort data. Patients hospitalized with newly diagnosed stroke from 2005 to 2015 were included and followed up for up to 10 years. The primary outcome was the development of PSE, defined as having a diagnostic code and a prescription for anti-seizure medication. Multivariable Cox proportional hazard models were used to estimate PSE hazard ratios (HRs), and time-varying effects were also assessed. A total of 8,305 patients with ischemic stroke, 1,563 with intracerebral hemorrhage (ICH), and 931 with subarachnoid hemorrhage (SAH) were included. During 10 years of follow-up, 4.6% of patients developed PSE. Among patients with ischemic stroke, significant risk factors for PSE were younger age (HR = 1.47), living in rural areas (HR = 1.35), admission through the emergency room (HR = 1.33), and longer duration of hospital stay (HR = 1.45). Time-varying analysis revealed elevated HRs for ICH and SAH, particularly in the first 2 years following the stroke. The age-specific HRs also showed an increased risk for those under the age of 65, with a noticeable decrease in risk beyond that age. The risk of developing PSE varies according to stroke subtype, age, and other demographic factors. These findings underscore the importance of tailored poststroke monitoring and management strategies to mitigate the risk of PSE.

Associations between Peritonsillar Abscess and Deep Neck Infection in Chronic Periodontitis Patients: Two Nested Case-Control Studies Using a National Health Screening Cohort.

Background/Introduction: Odontogenic infection is one of the main etiologies of deep neck infection (DNI). However, the relationship between chronic periodontitis (CP) and the incidence of DNI has not been examined. This study aimed to evaluate the incidence of DNI and peritonsillar abscess (PTA) after CP. Methods: The Korean National Health Insurance Service-National Sample Cohort 2002-2019 was used. In Study I, 4585 PTA patients were matched with 19,340 control I participants. A previous history of CP for 1 year was collected, and the odds ratios (ORs) of CP for PTA were analyzed using conditional logistic regression. In Study II, 46,293 DNI patients and 185,172 control II participants were matched. A previous history of CP for 1 year was collected, and conditional logistic regression was conducted for the ORs of CP for DNI. Secondary analyses were conducted in demographic, socioeconomic, and comorbidity subgroups. Results: In Study I, a history of CP was not related to the incidence of PTA (adjusted OR = 1.28, 95% confidence interval [CI] = 0.91-1.81). In Study II, the incidence of DNI was greater in participants with a history of CP (adjusted OR = 1.55, 95% CI = 1.41-1.71). The relationship between CP history and DNI was greater in groups with young, male, low-income, and rural residents. Conclusions: A prior history of CP was associated with a high incidence of DNI in the general population of Korea. Patients with CP need to be managed for the potential risk of DNI.

What is the relationship between the local population change and cancer incidence in patients with dyslipidemia: Evidence of the impact of local extinction in Korea.

Changes in the local population are intricately linked to healthcare infrastructure, which subsequently impacts the healthcare sector. A decreasing local population can result in lagging health infrastructure, potentially leading to adverse health outcomes as patients may be at risk of not receiving optimal care and treatment. While some studies have explored the relationship between chronic diseases and local population decline, evidence regarding cancer is insufficient. In this study, we focused on how deteriorating management of chronic diseases such as dyslipidemia could influence the risk of cancer. We investigated the relationship between changes in the local population and cancer incidence among patients with dyslipidemia. This cohort study was conducted using claims data. Data from adult patients with dyslipidemia from the National Health Insurance Service-National Sample Cohort conducted between 2002 and 2015 were included. Population changes in each region were obtained from the Korean Statistical Information Service and were used to link each individual's regional code. Cancer risk was the dependent variable, and Cox proportional hazards regression was used to estimate the target associations. Data from 336,883 patients with dyslipidemia were analyzed. Individuals who resided in areas with a decreasing population had a higher risk of cancer than those living in areas with an increasing population (decrease: hazard ratio (HR) = 1.06, 95% CI = 1.03-1.10; normal: HR = 1.05, 95% CI = 1.02-1.09). Participants living in regions with a low number of hospitals had a higher risk of cancer than those in regions with a higher number of hospitals (HR = 1.20, 95% CI = 1.12-1.29). Patients in regions where the population has declined are at a higher risk of cancer, highlighting the importance of managing medical problems caused by regional extinction. This could provide evidence for and useful insights into official policies on population decline and cancer risk.

Tuberculosis and Nontuberculous Mycobacterial Infections in Patients with Spondyloarthritis: A Population-Based Study.

Background and Objectives: Tuberculosis is caused by Mycobacterium tuberculosis (MTB), while nontuberculous mycobacteria (NTM) encompass a group of mycobacterial species that are distinct from the MTB complex and leprae. Spondyloarthritis (SpA) is a group of chronic inflammatory diseases with shared clinical characteristics and is treated with biological agents; however, their use may elevate the risk of MTB and NTM infections. This study aimed to compare the incidence and risk of MTB and NTM infections in patients with SpA, including ankylosing spondylitis (AS) and psoriatic arthritis (PsA), using a population-based approach. Materials and Methods: This study included 2333 patients with SpA and 9332 age- and sex-matched controls from the Korea National Health Insurance Service-National Sample Cohort database from 2002 to 2019. The patients were identified using the International Classification of Diseases-10 codes for AS, PsA, MTB, and NTM. Results: The results showed that a negligible percentage of patients with SpA developed NTM (0.002%) and MTB (0.016%), with no significant difference in the incidence rate ratio (IRR) compared to controls. Among patients with SpA treated with biologics, the IRRs for NTM and MTB were 5.66 and 3.069, respectively; however, these were not statistically significant. No cases of NTM or MTB infection were reported in female patients with SpA treated with biologics. In both the SpA patient group and the control group, the incidence of MTB was higher in individuals over 60 years old compared to those under 60 years old. Cox proportional hazard analysis revealed a significant adjusted hazard ratio of 1.479 for MTB in patients with SpA after adjusting for age, sex, smoking history, insurance level, and comorbidities. However, this significance was not maintained when biological therapy was further adjusted. Conclusions: Our study indicated that the risks of NTM and MTB infection are not elevated in patients with SpA. Although biological use may potentially increase the risk of MTB infection, it does not lead to a significant increase in incidence rates. Proactive screening for latent tuberculosis and adequate prophylaxis using biologics can effectively manage the risk of NTM and MTB infections.

Increased bronchiectasis risk and related risk factors in inflammatory bowel disease: A 10-year Korean national cohort study

BackgroundThe association between inflammatory bowel disease (IBD) and an increased risk of bronchiectasis, as well as contributing factors, remains unclear. Additionally, whether bronchiectasis increases disease burden in IBD remains unknown. Therefore, this study aimed to 1) assess whether IBD increases the risk of incident bronchiectasis; 2) compare the risk of bronchiectasis between individuals with Crohn's disease (CD) and those with ulcerative colitis (UC); 3) identify risk factors for bronchiectasis in individuals with IBD; and 4) examine the disease burden in individuals with IBD and bronchiectasisversusthose without.MethodsWe conducted a population-based matched cohort study involving adults aged ≥20 years with IBD, using data acquired from the National Health Insurance Service-National Sample Cohort database in Korea between 2002 and 2012.ResultsDuring the mean follow-up of 9.6 years, the incidence rate of bronchiectasis was 419.63/100 000 and 309.65/100 000 person-years (PY) in the IBD and matched cohorts (adjusted hazard ratio [aHR]=1.21, 95% confidence interval [CI]=1.05–1.39), respectively. UC was associated with increased bronchiectasis risk (aHR=1.42, 95% CI=1.19–1.69), while CD was not. Multivariate Cox regression analyses showed that age, male sex, medical aid, underweight status, chronic obstructive pulmonary disease, and diabetes mellitus were associated with an increased risk of bronchiectasis in the IBD cohort (p<0.05). The mortality, emergency department visit, and hospitalisation rates were significantly higher for individuals with IBD and bronchiectasis compared to those without bronchiectasis (p<0.05).ConclusionIBD is associated with increased risk of bronchiectasis, which results in a greater disease burden in individuals with IBD.

Osteoporosis Is Associated with an Increased Risk of Colorectal Neoplasms Regardless of Sex: Nationwide Population-Based Cohort Study.

Vitamin D may have anticancer effects against colorectal cancer (CRC). Bone mineral density (BMD) reflects the long-term vitamin D status. This study investigated the association between osteoporosis and colorectal neoplasms (CRN). The data were obtained from the National Health Insurance Service sample cohort, which included 60,386 osteoporosis patients and 8224 controls who underwent BMD in 2002-2019. The logistic regression models included age, sex, income level, and comorbidity. Sensitivity tests were performed using the data from the National Health Screening Program. In total, 7706 (11.2%) patients were diagnosed with CRN, and the proportion was significantly higher in osteoporosis patients than in controls (11.7% vs. 8.1%). In the multivariate analysis, osteoporosis was associated with an increased risk of CRN (odds ratio (OR) = 1.91, 95% confidence interval = 1.75-2.09, p < 0.0001), which was significant for both colorectal adenomas and CRC (OR = 1.88 and 1.83, respectively). A subgroup analysis by sex revealed a significant association between osteoporosis and CRN in both women and men (OR = 2.06 and 1.66, respectively). The sensitivity tests revealed results similar to those of the original dataset. In conclusion, osteoporosis is significantly associated with CRN risk in both sexes. In high-risk patients with low BMD, appropriate screening for CRN and vitamin D supplementation are required, regardless of sex.

Association of decreased estimated glomerular filtration rate with lung cancer risk in the Korean population.

Inconsistent results are available regarding the association between low estimated glomerular filtration rate (eGFR) and lung cancer risk. We aimed to explore the risk of lung cancer according to eGFR category in the Korean population. We included 358,293 adults who underwent health checkups between 2009 and 2010, utilizing data from the National Health Insurance Service-National Sample Cohort. Participants were categorized into 3 groups based on their baseline eGFR, as determined using the Chronic Kidney Disease Epidemiology Collaboration equation: group 1 (eGFR ≥90 mL/min/1.73m2), group 2 (eGFR ≥60 to <90mL/min/1.73m2), and group 3 (eGFR <60 mL/min/1.73m2). Incidences of lung cancer were identified using the corresponding codes from the International Classification of Diseases, 10th Revision. Multivariate Cox proportional hazard models were employed to calculate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer incidence up to 2019. In multivariate analysis, group 2 exhibited a 26.5% higher risk of developing lung cancer than group 1 (HR, 1.265; 95% CI, 1.189 to 1.346). Furthermore, group 3 demonstrated a 72.5% elevated risk of lung cancer relative to group 1 (HR, 1.725; 95% CI, 1.577 to 1.887). Among participants with dipstick proteinuria of 2+ or greater, group 3 faced a significantly higher risk of lung cancer than group 1 (HR, 2.928; 95% CI, 1.375 to 6.237). Low eGFR was significantly associated with increased lung cancer risk within the Korean population. A particularly robust association was observed in individuals with severe proteinuria, emphasizing the need for further investigation.

Association between Gout and Gastric Cancer: A Nested Case-Control Study Using a National Health Sample Cohort.

Given the global significance of gout and gastric cancer (GC) as major health problems with interrelated impacts, we examined the development of GC in Korean patients with gout. We conducted a nested case-control study using data from 10,174 GC patients and 40,696 control patients from the Korean National Health Insurance Service-National Sample Cohort database. Propensity score matching (1:4) with propensity score overlap-weighted adjustment was used to reduce selection bias and estimate the odds ratio (OR) and 95% confidence intervals (CIs) for the association between gout and GC. An adjusted OR for GC was not significantly higher in patients with gout than in control patients (1.02; 95% CI, 0.93-1.12; p = 0.652). Additionally, no association between gout and GC was observed in subgroup analyses such as sex, age, level of income, region of residence, or Charlson Comorbidity Index score. In conclusion, these results suggest that gout is not a significant independent risk factor for GC among the Korean population. Additional investigation is required to establish a causal association between gout and GC, and to generalize these results to general populations.

Association Between Eight Autoimmune Diseases and Thyroid Cancer: A Nationwide Cohort Study.

Background: It has often been reported that thyroid-specific autoimmune diseases (ADs), such as Hashimoto's thyroiditis and Graves' disease, could increase the risk of thyroid cancer, but the association between other ADs beyond thyroid and thyroid cancer has not been well investigated. This study aimed to examine the risk of thyroid cancer in patients with eight ADs compared with those without ADs. Methods: This nationwide retrospective matched cohort study was conducted to investigate the relationship of eight ADs (Hashimoto's thyroiditis, Graves' disease, type 1 diabetes mellitus, Sjogren's disease, inflammatory bowel disease [IBD], vitiligo, systemic lupus erythematosus, and rheumatoid arthritis [RA]) with the risk of incident thyroid cancer using the National Health Insurance Service-National Sample Cohort. The Cox-proportional hazard model was used to estimate the adjusted hazard ratio (HR) and confidence intervals (CI) for thyroid cancer in relation to each of AD compared with control group without AD. Results: During the average follow-up of 9.49 years, 138 thyroid cancer cases were newly developed in control group and 268 cases were occurred in group with 8 ADs. For all of study participants, the risk of thyroid cancer was significantly increased in patients with Hashimoto's thyroiditis (HR = 2.10 [1.57-2.81]), Graves' disease (HR = 2.67 [1.99-3.62]), IBD (HR = 2.06 [1.50-2.83]), vitiligo (HR = 1.71 [1.13-2.59]), RA (HR = 1.76 [1.07-2.90]), and total of 8 ADs (HR = 1.97 [1.60-2.42]) compared with control group without ADs. When ADs were divided into three types, thyroid-specific ADs (HR = 2.37 [1.85-3.03]) showed the strongest and significant association with thyroid cancer, followed by local ADs (HR = 1.83 [1.41-2.38]), and systemic ADs (HR = 1.77 [1.14-2.74]). Conclusions: Specific ADs-especially for thyroid-specific AD, vitiligo, IBD, and RA-were associated with increased risk for thyroid cancer.

Screening patients requiring secondary lumbar surgery for degenerative lumbar spine diseases: a nationwide sample cohort study

This study aims to identify healthcare costs indicators predicting secondary surgery for degenerative lumbar spine disease (DLSD), which significantly impacts healthcare budgets. Analyzing data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database of Republic of Korea (ROK), the study included 3881 patients who had surgery for lumbar disc herniation (LDH), lumbar spinal stenosis without spondylolisthesis (LSS without SPL), lumbar spinal stenosis with spondylolisthesis (LSS with SPL), and spondylolysis (SP) from 2006 to 2008. Patients were categorized into two groups: those undergoing secondary surgery (S-group) and those not (NS-group). Surgical and interim costs were compared, with S-group having higher secondary surgery costs ($1829.59 vs $1618.40 in NS-group, P = 0.002) and higher interim costs ($30.03; 1.86% of initial surgery costs vs $16.09; 0.99% of initial surgery costs in NS-group, P < 0.0001). The same trend was observed in LDH, LSS without SPL, and LSS with SPL (P < 0.0001). Monitoring interim costs trends post-initial surgery can effectively identify patients requiring secondary surgery.

Is arthritis an associated risk factor for trigger finger occurrence after carpal tunnel release? A nationwide, population-based study in Korea.

We hypothesized that increased friction between the flexor tendon and surrounding structures due to hand arthritis is an important risk factor for trigger finger (TF) after carpal tunnel release (CTR). Therefore, we compared TF development according to the presence or absence of arthritis in carpal tunnel syndrome (CTS) patients treated with CTR. This retrospective study was based on data collected from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) in the Republic of Korea between January 1, 2002, and December 31, 2015. Patients diagnosed with TF between one month and one year after the CTR date or with a history of surgery were included in the study. During subsequent follow-up, the patients were divided into subgroups of those (1) with TF and (2) without TF. Sex, age, arthritis, and TF-related comorbidities were compared between the subgroups. The subgroup with TF had a higher proportion of women (9.43% vs 90.57%), the highest age range between 50 and 59 years, more cases of arthritis (32.55% vs 16.79%), and a higher proportion of patients with hypothyroidism (10.85% vs 4.60%) than the group without TF. The association between arthritis and TF after CTR was examined using a multivariate logistic regression model, showing arthritis to be a significant risk factor for TF after CTR (odds ratio, 1.35; P = 0.049). We identified arthritis as an important risk factor for the development of TF after CTR.

Trends in Incidence and Drug Prescriptions for Croup in Children Under 5 Years of Age: A 2002-2019 Population-Based Study.

Tracking national croup trends can provide important insights for childhood health management. This study aimed to analyze the incidence and drug prescription trends in Korean children over a two-decade period. This population-based study encompassed 479,783 children aged < 5 years from 2002-2019, utilizing the National Health Insurance Service-National Sample Cohort. We identified participants with a primary croup diagnosis who were admitted to or visited the emergency room. Age-specific and age-adjusted incidence rates/10,000 person-years were calculated. We assessed using orthogonal polynomial contrasts and stratified by various factors (sex, age, residential area, economic status, comorbidities, and healthcare facility types). We observed changes in the use of five medications: inhaled steroids, systemic steroids, inhaled epinephrine, antibiotics, and short-acting bronchodilators. Generalized binomial logistic regression was used to analyze factors influencing prescription strategies. In 2002, the croup-related visits were 16.1/10,000 person-years, increasing to 98.3 in 2019 (P for trend < 0.001). This trend persisted, regardless of age, sex, region, and economic status. Children with comorbid atopic dermatitis or asthma maintained consistent croup rates, while those without comorbidities increased. Treatment trends showed decreasing antibiotic (73-47%) and oxygen use (21.3-3.4%), with increasing nebulized epinephrine (9.3-41.5%) and multiple drug prescriptions (67.8-80.3%). Primary care centers exhibited a greater increase in prescription usage and hospitalization duration than did tertiary healthcare institutions. Over the past two decades, croup incidence has risen, accompanied by increased epinephrine use and decreased antibiotic prescriptions. Longer hospitalization and higher medication use were mainly observed in primary care facilities.

Limaprost and the Risk of Bleeding: A Self-Controlled Case Series Study.

To investigate the association between the use of limaprost and the risk of bleeding. A self-controlled case series analysis was conducted using the National Health Insurance Service-National Sample Cohort database in South Korea. We identified patients aged 18 years or older who had at least one prescription of limaprost and were diagnosed with at least one case of bleeding between 2003 and 2019. The incidence rate ratio (IRR) of bleeding was calculated by dividing the incidence rate in the exposed period to limaprost by that in the unexposed period and adjusted for age using conditional Poisson regression model. Among 72,860 patients with limaprost prescriptions and bleeding diagnoses, there were 184,732 events of bleeding. After adjusting for age, the IRR was 1.47 (95% confidence interval [CI], 1.43-1.50), wherein the IRR was the highest during the 0-7 days after limaprost initiation (IRR, 2.11; 95% CI, 2.03-2.18). Risk of bleeding was higher when limaprost was concomitantly used with antithrombotics or other drugs for spinal stenosis treatment, and when higher daily doses of limaprost were administered. Our findings suggest that the risk of bleeding increased by 1.5-fold in periods of limaprost exposure compared to unexposed periods, with particularly higher risks observed during the first week after limaprost initiation, with concomitant drugs related to bleeding, and with a higher daily dose. A careful risk-benefit assessment is warranted when initiating limaprost, especially when administered with other medications or in higher daily doses.

Association between subconjunctival hemorrhage and hemorrhagic disorders: a nationwide population-based study

Subconjunctival hemorrhage (SCH) is a benign eye condition that is often noticeable and leads to medical attention. Despite previous studies investigating the relationship between SCH and cardiovascular diseases, the relationship between SCH and bleeding disorders remains controversial. In order to gain further insight into this association, a nationwide cohort study was conducted using data from the National Health Insurance Service-National Sample Cohort version 2.0 from 2006 to 2015. The study defined SCH using a diagnostic code and compared the incidence and risk factors of intracerebral hemorrhage (ICH) and gastrointestinal (GI) bleeding in 36,772 SCH individuals and 147,088 propensity score (PS)-matched controls without SCH. The results showed that SCH was associated with a lower risk of ICH (HR = 0.76, 95% CI = 0.622–0.894, p = 0.002) and GI bleeding (HR = 0.816, 95% CI = 0.690–0.965, p = 0.018) when compared to the PS-matched control group. This reduced risk was more pronounced in females and in the older age group (≥ 50 years), but not observed in males or younger age groups. In conclusion, SCH dose not increase the risk of ICH and major GI bleeding and is associated with a decreased incidence in females and individuals aged ≥ 50 years.

Trend of incidence rate of age-related diseases: results from the National Health Insurance Service–National Sample Cohort (NHIS-NSC) database in Korea: a cross- sectional study

BackgroundThis study aimed to identify and select age-related diseases (ARDs) in Korea, which is about to have a super-aged society, and to elucidate patterns in their incidence rates.MethodsThe National Health Insurance Service–National Sample Cohort, comprising 1 million health insurance and medical benefit beneficiaries in Korea from 2002 to 2019, was utilized. We selected 14 diseases with high disease burden and prevalence among Koreans from the 92 diseases defined in the Global Burden of Diseases, Injuries, and Risk Factors Study as ARDs. The annual incidence rate represented the number of patients newly diagnosed with an ARD each year from 2006 to 2019, excluding those with a history of ARD diagnosis from 2002 to 2005. The incidence rate by age was categorized into 10-year units based on age as of 2019. The number of patients with ARDs in each age group was used as the numerator, and the incidence rate for each age group was calculated with the age group as the denominator.ResultsRegarding the annual incidence rates of ARDs from 2006 to 2019, chronic obstructive pulmonary disease, congestive heart failure, and ischemic heart disease decreased annually, whereas dyslipidemia, chronic kidney disease, cataracts, hearing loss, and Parkinson's disease showed a significant increase. Hypertension, diabetes, cerebrovascular disease, osteoporosis, osteoarthritis, and age-related macular degeneration initially displayed a gradual decrease in incidence but exhibited a tendency to increase after 2015. Concerning age-specific incidence rates of ARDs, two types of curves emerged. The first type, characterized by an exponential increase with age, was exemplified by congestive heart failure. The second type, marked by an exponential increase peaking between ages 60 and 80, followed by stability or decrease, was observed in 13 ARDs, excluding congestive heart failure. However, hypertension, ischemic heart disease, cerebrovascular disease, chronic obstructive pulmonary disease, and hearing loss in men belonged to the first type.ConclusionsFrom an epidemiological perspective, there are similar characteristics in age-specific ARDs that increase with age, reaching a peak followed by a plateau or decrease in Koreans.

Cancer risks in patients with ankylosing spondylitis and the effects of biologic agents: a population-based study

Abstract Objective The objective of this study was to conduct a population-based analysis of the malignancy risks of patients with AS. Methods A total of 1796 patients with AS and 7184 age- and sex-matched controls (1:4 ratio) were selected from the Korea National Health Insurance Service–National Sample Cohort database. Data of patients diagnosed with AS (code M45) according to the International Classification of Diseases (ICD) 10th edition, between 2002 and 2019, were reviewed. These data were extracted based on the ICD codes assigned to cancer patients. Results Cancer developed in 168/1796 patients (9.3%) after the AS diagnosis. After adjusting for confounders, the cancer risk of patients with AS was not significantly increased compared with that of controls [adjusted hazard ratio (HR): 1.1; 95% CI: 0.93–1.31]. However, the risks for upper gastrointestinal (GI) cancer (adjusted HR: 1.51; 95% CI: 1.07–2.12) and haematologic malignancy (adjusted HR: 2.36; 95% CI: 1.2–4.65) were significantly higher in patients with AS than in controls. There were no significant differences in the risks for other major cancers between patients with AS and controls. Regarding medication for AS, the HR of upper GI cancer was higher in patients with AS compared with controls (adjusted HR: 1.51; 95% CI: 1.00–2.29). Conclusion The overall cancer risk in patients with AS was not significantly different compared with that in the controls. However, while the effect of NSAIDs on upper GI cancer cannot be ruled out, patients with AS exhibited a significant increase in the risk of both upper GI cancer and haematologic malignancy.

Association between long-term PM2.5 exposure and risk of Kawasaki disease in children: A nationwide longitudinal cohort study

BackgroundBased on previous studies suggesting air pollution as a potential risk factor for Kawasaki Disease (KD), we examined the association of long-term exposure to childhood fine particulate matter (PM2.5) with the risk of KD. MethodsWe used National Health Insurance Service–National Sample Cohort data from 2002 to 2019, which included beneficiaries aged 0 years at enrollment and followed-up until the onset of KD or age 5 years. The onset of KD was defined as the first hospital visit record with a primary diagnostic code of M30.3, based on the 10th revision of the International Classification of Diseases, and with an intravenous immunoglobulin (IVIG) prescription. We assigned PM2.5 concentrations to 226 districts, based on mean annual predictions from a machine learning-based ensemble prediction model. We performed Cox proportional-hazards modeling with time-varying exposures and confounders. ResultsWe identified 134,634 individuals aged five or less at enrollment and, of these, 1220 individuals who had a KD onset and an IVIG prescription during study period. The average annual concentration of PM2.5 exposed to the entire cohort was 28.2 μg/m³ (Standard Deviation 2.9). For each 5 μg/m³ increase in annual PM2.5 concentration, the hazard ratio of KD was 1.21 (95% CI 1.05–1.39). ConclusionsIn this nationwide, population-based, cohort study, long-term childhood exposure to PM2.5 was associated with an increased incidence of KD in children. The study highlights plausible mechanisms for the association between PM2.5 and KD, but further studies are needed to confirm our findings.

Association Between Acid-Suppressive Drugs and Risk of Rosacea: Retrospective Study Using the Korean National Health Insurance Service-National Sample Cohort.

Rosacea is a common inflammatory skin disease with multiple etiologies. Proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RA) are acid suppressive drugs widely used for gastrointestinal (GI) diseases, and long-term use has been reported to be associated with dysbiosis which is a potential risk for development of rosacea. This study aimed to study the association between rosacea and acid suppressants in the Korean national cohort. We used Korean National Health Insurance Service-National Sample Cohort data of 749,166 patients with upper GI diseases between 2001 and 2013. Duration of acid suppressants was compared between patients with and without rosacea together with other sociodemographic characteristics and hazard ratios were estimated. Longer use of acid suppressants was significantly associated with increased risk of rosacea. After adjustment for possible confounders, increased cumulative defined daily dose was significantly associated with risk of rosacea (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.20-2.00; P = 0.001). Other factors significantly associated with risk of rosacea include residing in the rural area (OR, 2.58; 95% CI, 2.18-3.06; P < 0.001), greater Charlson Comorbidity Index score (OR, 1.45; 95% CI, 1.15-1.83; P = 0.002), and comorbidities (malignancy, thyroid disease, and depression). Results from our study indicate that H2RA or PPI is associated with the occurrence of rosacea among patients with GI diseases in the Korean population. The risk was increased in dose-dependent manner, even after adjusting for confounding variables. Clinicians should be aware of risks associated with prolonged use of acid suppressive drugs.