Search Results (172)

Background/Objectives: The two major subtypes of inflammatory bowel disease (IBD)—Crohn’s disease (CD) and ulcerative colitis (UC)—are known to increase the likelihood of developing colorectal cancer (CRC). While this relationship has been well studied in Western populations, evidence from East Asia remains limited and inconsistent. Using nationwide cohort data, this study explored the potential connection between IBD and CRC in a large Korean population. Methods: We conducted a retrospective cohort study using data from the Korean National Health Insurance Service–National Sample Cohort from 2005 to 2019. A total of 9920 CRC patients were matched 1:4 with 39,680 controls using propensity scores based on age, sex, income, and region. Overlap weighting and multivariable logistic regression were used to evaluate the association between IBD and CRC. Subgroup analyses were conducted to assess effect modification by demographic and clinical factors. Results: IBD markedly increased the likelihood of developing CRC (adjusted odds ratio (aOR) = 1.38; 95% confidence interval (CI): 1.20–1.58; p < 0.001), with the association primarily driven by UC (aOR = 1.52; 95% CI: 1.27–1.83). CD appeared unrelated to heightened CRC risk overall, though a significant association was observed among low-income CD patients (aOR = 1.58; 95% CI: 1.15–2.16). The UC–CRC association persisted across all subgroups, including patients without comorbidities. Conclusions: Our findings support an independent association between IBD—particularly UC—and increased CRC risk in Korea. These results underscore the need for personalized CRC surveillance strategies that account for disease subtype, comorbidity burden, and socioeconomic status, especially in vulnerable subpopulations. Full article

Background/Objectives: Urban green space has been increasingly recognized as a determinant of maternal and child health. This study investigated the association between prenatal exposure to different types of green space and the risk of congenital anomalies in South Korea. Methods: We analyzed data from the National Health Insurance Service (N = 142,422). Green space exposure was measured at the area level and categorized into grassland and forest; statistical analysis was performed using generalized estimating equations and generalized additive models to analyze the associations. Additionally, subgroup and sensitivity analyses were performed. Results: GEE analysis showed that a 10% increase in the proportion of grassland in a residential district was associated with a reduced risk of nervous system (adjusted odds ratio [aOR]: 0.77, 95% confidence interval [CI]: 0.63–0.94) and genitourinary system anomalies (aOR: 0.83, 95% CI: 0.71–0.97). The subgroup analysis results showed significance only for male infants, but the difference between the sexes was not significant. In the quartile-based analysis, we found a slightly significant p-value for trend for the effect of forests on digestive system anomalies, but the trend was toward increasing risk. In a sensitivity analysis with different exposure classifications, the overall and nervous system anomalies in built green space showed that the risk decreased as green space increased compared to that in the lowest quartile. Conclusions: Our results highlight the importance of spatial environmental factors during pregnancy and suggest that different types of green spaces differentially impact the offspring’s early health outcomes. This study suggests the need for built environment planning as part of preventive maternal and child health strategies. Full article

Background and Objectives: Air pollutants have been shown to affect hypertensive disorders and placental hypoxia due to vasoconstriction, inflammation, and oxidative stress. The objective of this study was to evaluate whether high levels of maternal exposure to heavy metals during the second trimester of pregnancy are associated with an increased risk of preeclampsia and eclampsia, using national health insurance claim data from South Korea. Methods: Data on mothers and their newborns from 2016 to 2020, provided by the National Health Insurance Service, were used (n = 1,274,671). Exposure data for ambient air pollutants (PM2.5, CO, SO₂, NO₂, and O₃) and heavy metals (Pb, Cd, Cr, Cu, Mn, Fe, Ni, and As) during the second trimester of pregnancy were retrieved from the Korea Environment Corporation. Atmospheric condition data based on the mother’s registration area were matched. A logistic regression model was adjusted for maternal age, infant sex, season of conception, and household income. Results: In total, 16,920 cases of preeclampsia and 592 cases of eclampsia were identified. In the multivariate model, copper exposure remained significantly associated with an increased risk of preeclampsia (odds ratio: 1.011; 95% confidence interval: 1.001–1.023), and higher ozone exposure during pregnancy was associated with an elevated risk of eclampsia. Conclusions: Increased copper exposure during the second trimester of pregnancy was associated with a high incidence of preeclampsia. Full article

In postmenopausal women, the prevalence of hypertension increases sharply, emphasizing the importance of its prevention. This increased risk highlights the critical need for effective prevention strategies specifically designed for this population. To address this issue, the present study aimed to identify easily measurable risk factors that contribute to hypertension in postmenopausal women using explainable artificial intelligence (XAI) and machine learning (ML) techniques. This study conducted hypertension classification by analyzing health checkup data from 3289 postmenopausal Korean women aged 55–79 years, extracted from the 2022–2023 Korea National Health Insurance Service (KNHIS) database, using XGBoost, SVM and ANN. XGBoost was the most effective model (AUC: 92.12%, MCC: 0.71) in hypertension classification. Shapley Additive exPlanations-based feature importance identified age and waist circumference (WC) as the most important risk factors for hypertension. In this study, blood pressure increased with variations in WC, a modifiable risk factor. These findings suggest that WC should be managed more strictly to prevent hypertension in postmenopausal women. Full article

Background/Objectives: The outbreak of coronavirus disease 2019 (COVID-19) has restricted access to healthcare, increasing the risk of poor disease control among patients with COPD (Chronic Obstructive Pulmonary Disease). This study aimed to compare adherence to inhalers in patients with COPD before and during the COVID-19 lockdown and determine the characteristics of patients who were adherent to inhaler medications. Method: A retrospective analysis was conducted on a cohort of patients with severe COPD aged 40 or older using South Korea’s National Health Insurance Service (NHIS) database, which documents all healthcare utilization covered for insured individuals. Medication adherence, measured by the proportion of days covered (PDC), was compared before and during the COVID-19 lockdown using a paired t-test. A multivariable logistic regression model was conducted to identify the characteristics of the adherent patients (socio-demographic, including age, sex, income level, insurance type, and residential area), health-conditions (disease severity, underlying diseases, and disability), and pharmacotherapy characteristics (prescriber practice setting, polypharmacy, medication treatment duration, and inhaler type). Result: A total of 15,971 COPD patients were identified (79.2% men). During the COVID-19 lockdown in 2020, there was a significant decrease in medication adherence to COPD inhalers compared to 2019 (49.8% in 2020 vs. 56.3% in 2019, respectively; p < 0.001). Moreover, the proportion of those adherent (≥80%) during the COVID-19 lockdown decreased (22.0% → 18.0%). Patients who remained adherent to inhaler therapy during the COVID-19 lockdown were typically aged in their 60s, beneficiaries of Medical Aid, residents of rural areas, clinic users, and patients without cardiovascular disease. Conclusions: Patients with COPD encountered significant challenges in accessing inhalers during the COVID-19 lockdown. Healthcare authorities should develop targeted strategies to ensure continued medication access for patients at increased risk of poor medication adherence, particularly during periods of restricted healthcare access, such as public health emergencies or pandemic lockdowns. Full article

Background/Objectives: Parkinson’s disease (PD) is a major neurodegenerative condition, mainly treated using dopamine-based therapies. However, the side effects and limitations of these therapies hinder their use. This study aimed to analyze the utilization of Korean medicine (KM) by patients with PD in Korea. Methods: Data of the Health Insurance Review and Assessment Service–National Patient Sample were used to investigate the status and trend of KM utilization by patients with PD in Korea from January 2010 to December 2019. Data of 18,562 patients were included, and analyses were performed on the status of KM and Western medicine (WM) utilization, cost of care, prescribed medications, comorbidities, and characteristics of patients with PD. Results: The number of patients who utilized KM services for PD gradually increased over the 10-year period, with 10.6% of all patients with PD using KM services in 2019. In addition, the number of KM users with PD, number of claims, and expenses all showed an increase. The rate of increase in KM service utilization was greater than that of WM. Among KM services, acupuncture had the highest expense (50.6%). Regarding comorbidities in patients with PD, musculoskeletal diseases were the most common (58.6%). Among WM medications prescribed for the KM users, dopa and dopa derivatives (15.5%) and anti-dementia drugs (11.7%) were the most common. Conclusions: This study provides useful information on KM utilization status and trends among patients with PD and the characteristics of these patients. Follow-up research is warranted on the utilization status of more diverse KM services. Full article

Background: Socioeconomic status (SES) disparities impact health outcomes, but their effect on vascular access (VA) in hemodialysis patients in Korea remains underexplored. Methods: This study evaluated the association between SES and VA outcomes using National Health Insurance Service data from 2008 to 2019. Incident hemodialysis patients were categorized by insurance status into the health insurance group (HG) and medical aid group (MG). The primary endpoint was VA patency, and the secondary endpoint was all-cause mortality, adjusted for demographics, comorbidities, and lifestyle factors. Results: Among 86,036 patients, the MG (12.1%) was younger at VA creation (60.4 ± 13.5 vs. 63.1 ± 13.6 years, p < 0.001) and had higher rates of comorbidities (all p < 0.05 except cancer). Mortality rates per 100 person-years were higher in the MG (11.66 vs. 9.24 for AVF; 17.94 vs. 16.92 for AVG), as was the total procedure frequency (2.10 vs. 1.87, p < 0.001), despite similar percutaneous angioplasty counts (1.20 vs. 1.24, p = 0.314). Conclusions: Lower SES patients exhibited poorer VA patency and higher mortality rates despite equitable healthcare access and cost coverage in Korea. These findings suggest that non-medical factors, such as adherence to treatment and timely intervention, play a critical role in mitigating these disparities. Full article

Background: Assessing recent changes in mortality among patients undergoing hemodialysis (HD) can help both to identify the causes of death most closely associated with these changes and to develop prevention strategies. This study explored trends in all-cause and cause-specific mortality among patients undergoing HD in South Korea using an analysis of national data. Methods: We used national death certificate and claims data from 2003 to 2021 provided by the National Health Insurance Service. Age-standardized mortality rates (ASRs) were calculated by standardizing to the 2011 population of patients undergoing HD. Joinpoint regression analysis was performed to calculate the annual percentage change (APC) in mortality. All-cause and cause-specific ASRs and APCs were evaluated for the study period. Results: The proportion of male and older adult patients increased over time. In particular, the proportion of patients aged ≥ 80 years in the 2018–2021 period was more than 4 times higher than in the 2003–2007 period. From 2003 to 2021, there were a total of 136,302 deaths among patients undergoing HD in South Korea. Cardiovascular causes accounted for 13.6% of deaths, and the majority (86.4%) were attributed to noncardiovascular causes. In 2003, the all-cause ASR was 174.1 per 1000 person-years, which steadily decreased to 114.5 per 1000 person-years in 2021. The ASR from cardiovascular disease remained unchanged from 2003 to 2013 but increased by 3.9% (95% confidence interval: 1.3 to 14.0) per year from 2013 to 2021. In contrast, the ASR from noncardiovascular disease decreased during the study period. Conclusions: Nationally representative data showed a declining trend in the ASR among patients undergoing HD from 2003 to 2021. Noncardiovascular disease mortality decreased during the study period, while cardiovascular disease mortality increased. Full article

Background and Objectives: Low back pain (LBP) is a highly prevalent musculoskeletal condition that frequently recurs, leading to increased healthcare utilization and socioeconomic burden. While short-term management strategies are well-documented, long-term recurrence patterns remain insufficiently studied. This study aims to describe the long-term recurrence patterns and healthcare utilization associated with LBP in a nationwide cohort over a 17-year period. Materials and Methods: This descriptive, retrospective longitudinal cohort study utilized data from the Korean National Health Insurance Service (NHIS) database (2002–2018). We included 3,086,665 patients who sought medical care for LBP (ICD-10 code M54.5) at least once in 2010. Patients with a history of disability rating assessments were excluded. The primary outcomes included the number of LBP episodes, episode duration, recurrence patterns, and changes in healthcare utilization. We assessed the number of healthcare visits per episode and the interval between episodes over time. Results: Among the study population, 79.4% experienced recurrent LBP, with an average of 5.0 ± 4.9 episodes per patient. Recurrence rates increased with each episode. In addition, episode duration lengthened, and intervals between episodes shortened. Healthcare utilization also increased, with patients requiring more visits per episode over time. The demographic and socioeconomic characteristics of the LBP patients in our sample were also described. Conclusions: In this population-based sample, LBP follows a progressive course, with increasing episode frequency, prolonged duration, and escalating healthcare utilization over time. These findings highlight the need for early intensive management and long-term follow-up strategies to mitigate the growing burden of recurrent LBP on individuals and healthcare systems. Full article

Objective: The association between periodontitis and benign prostatic hyperplasia (BPH) has been controversial. This study aimed to estimate the association between recurrent periodontitis episodes and the occurrence of BPH in an adult male population in Korea. Methods: This study analyzed data from 79,497 matched cases and controls to examine the relationship between periodontitis and BPH, using Korean National Health Insurance Service-Health Screening Cohort data. Conditional logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs), adjusting for confounding factors. Results: The odds of BPH were significantly higher for participants with periodontitis ≥ 1 within 1 year (OR = 1.34, 95% CI = 1.31–1.37), particularly in low-income individuals (OR = 1.43, 95% CI = 1.38–1.48). Increased periodontitis frequency (≥2 or ≥3 within 1 year) and a CCI score ≥ 2 were associated with progressively higher odds of BPH, indicating that periodontitis may be a significant risk factor for BPH, with variations depending on socioeconomic and health status. Conclusions: The occurrence of BPH was higher in participants with a history of recurrent periodontitis episodes, with stronger associations observed in those with low income or multiple comorbidities. Clinicians should be aware of the potential risk of BPH in patients with recurrent periodontitis episodes. This study’s retrospective design, reliance on ICD-10 codes without details on disease severity, and focus on Korean citizens over 40 limit its ability to establish causality and generalizability to other populations and age groups, which should be considered when interpreting the findings. Full article

Background/Objectives: The triglyceride/high-density lipoprotein (TG/HDL) ratio serves as a simple marker for insulin resistance. We investigated whether the TG/HDL ratio would be associated with the incidence risk of heart failure (HF). Methods: The study utilized data from the National Health Insurance Service-Health Screening Cohort database of South Korea from 2002 to 2019. The TG/HDL ratio was utilized as a time-dependent covariate or average value of at least three times throughout the follow-up period. The outcome of interest was incident heart failure (HF) corresponding with the International Classification of Disease, Tenth Revision code of I50. Results: A total of 293,968 individuals were included in this study. During the median 9.6 years (interquartile range 9.2–10.13), 27,852 individuals (9.47%) had a cumulative incidence of HF. Considering the multivariable time-dependent Cox proportional hazard model with the repeated measures of the TG/HDL ratio, per unit increase in the TG/HDL ratio significantly increased the risk of HF in the entire cohort (hazard ratio (HR): 1.007, 95% confidence interval (CI): 1.002–1.011), diabetes mellitus (DM) cohort (HR: 1.006. 95% CI: 1.002–1.010), and non-DM cohort (HR: 1.008, 95% CI: 1.003–1.013). Regarding average TG/HDL ratio quartiles, compared to the lowest quartiles (Q1), the highest quartiles (Q4) were positively associated with the incidence risk of HF accompanied by a significant p for trend (HR: 1.114, 95% CI: 1.075–1.155) in fully adjusted multivariable analysis. Conclusions: Our study demonstrated that the repeatedly measured TG/HDL ratio was associated with the incidence risk of HF regardless of the presence of DM history in the general population. Full article

Objectives: This study aimed to classify fasting blood glucose (FBG) trajectories by sex and examine their associations with the risk of chronic kidney disease (CKD). Methods: Using data from the National Health Insurance Service-National Sample Cohort in Korea, participants aged 40 years and above, without CKD or diabetes mellitus (DM), were followed from 2002 to 2009. Based on their FBG trajectories, participants were categorized into two classes and stratified by sex. CKD incidence rates were analyzed according to these FBG trajectories, and the impact of additional risk factors on CKD incidence was assessed. Results: A total of 91,131 participants were analyzed. Among individuals classified in Class 1, FBG levels gradually increased from 90.7 (men) and 88.7 (women) in 2002 to 96.6 (men) and 93.2 (women) in 2009. In contrast, participants classified as Class 2 exhibited a rapid increase in FBG levels, rising from 106 (men) and 106 (women) in 2002 to 144 (men) and 132 (women) in 2009. The incidence of CKD increased over time in both men and women classified as Class 2 compared to Class 1, with respective hazard ratios (HR) of 1.35 for men and 1.53 for women. Additionally, increased age, hypertension, and body mass index (BMI) were independently associated with an elevated risk of CKD. Conclusions: The Class 2 group demonstrated a significantly higher incidence of CKD compared to the Class 1 group. This finding indicates the need for the proactive management of individuals with relatively high FBG levels featuring rapid FBG increases in order to mitigate the risk of CKD development. Full article

Background: We aimed to investigate the association between acute carbon monoxide (CO) poisoning and the risk of internal malignancies, including hematologic malignancies. Methods: The study population was derived from the National Health Insurance Service (NHIS) database of Korea between 2002 and 2022. Adults diagnosed with CO poisoning and controls were included. Demographics, socioeconomic statuses, lifestyle factors, and comorbidity profiles of participants were retrieved from the NHIS database. Covariates potentially associated with disease outcomes were selected based on the available literature and biological plausibility, balanced between the two cohorts using inverse probability of treatment weighting, and applied to adjust multivariable models. Results: Overall, 42,874 patients with CO poisoning and 905,285 controls were included; both cohorts comprised 44.3% females. The mean age of the CO poisoning and controls was 51.5 and 50.9 years, respectively. Patients with CO poisoning had a 1.02-fold increase in the overall risk of malignancy (a 1.03-fold increase in solid organ malignancies and a 0.71-fold decrease in hematologic malignancies) compared with controls. The risk of internal malignancy was increased in the oral cavity (adjusted hazard ratio, 1.33; 95% confidence intervals, 1.19–1.49), lungs (1.39; 1.33–1.46), bone (1.68; 1.23–2.30), cervix (1.32; 95% CI, 1.17–1.49), and kidneys (1.14; 1.04–1.24). Conversely, the risk of internal malignancies was decreased in the thorax (0.59; 0.45–0.77), anus (0.14; 0.06–0.34), uterus (0.71; 0.60–0.82), ovaries (0.59; 0.45–0.77), prostate (0.89; 0.84–0.95), Hodgkin lymphoma (0.35; 0.20–0.61), non-Hodgkin lymphoma (0.67; 0.59–0.75), and multiple myeloma (0.36; 0.30–0.43). Conclusions: CO poisoning was associated with the development of internal malignancies. Full article

Background/Objectives: Uterine leiomyomas are the most common benign gynecological tumors in women of reproductive age and are often associated with localized symptoms. However, emerging evidence suggests a link between uterine leiomyomas and systemic conditions such as cardiovascular disease (CVD), particularly myocardial infarction (MI) and ischemic stroke (IS). This study aimed to investigate the relationship between uterine leiomyomas and the risk of CVD events in young women aged 20–39 years using a large, nationwide, population-based cohort. Methods: This retrospective cohort study analyzed data from the National Health Insurance Service database of South Korea of 2,581,700 women aged 20–39 years who underwent health screening between 2009 and 2012. Uterine leiomyomas were identified using International Code of Disease, 10th Edition codes. CVD events (MI and IS) were defined according to hospital claims and radiological data. Multivariate hazard ratios (HRs) were calculated to evaluate the association between leiomyomas and CVD after adjusting for confounders (age, lifestyle factors, comorbidities, and body mass index). Results: In all, 58,812 were diagnosed with uterine leiomyomas, and 25,063 underwent surgical treatment. During the follow-up period, MI occurred in 115 women (0.21%) and IS in 82 women (0.15%) in the leiomyoma group, compared with 3107 cases of MI (0.12%) and 2240 cases of IS (0.09%) in the non-leiomyoma group. The leiomyoma group demonstrated a higher incidence rate of CVD (IR: 0.63 vs. 0.39 per 1000 person-years). After adjusting for confounding factors such as age, lifestyle, comorbidities, and body mass index (BMI), the hazard ratio (HR) for MI was 1.32, indicating a statistically significant increase in cardiovascular risk. The risk of CVD was lower in women who underwent surgical treatment; however, when specifically analyzing the occurrence of MI and IS, no statistically significant differences were observed between the two groups. Conclusions: Uterine leiomyomas are associated with an increased risk of MI and IS in young women. Surgical treatment itself may be associated with additional cardiovascular risks. Further research is needed to develop strategies to mitigate these risks and elucidate the underlying mechanisms. Full article

Snakebites are a significant global health concern; despite various known risk factors, the role of environmental changes, such as deforestation, remains underexplored. Therefore, we investigated the association between deforestation and snakebite incidence in South Korea. Aggregated data were obtained from the National Health Insurance Service (NHIS) and the National Emergency Department Information System (NEDIS) from 2014 to 2021. The main explanatory variable was the level of deforestation by district and year. Additional covariates included altitude, average temperature, population size, proportion of urban land cover, proportion of agricultural land cover, and level of ecological preservation. Twelve statistical models were employed to assess the association between deforestation and snakebite incidence. The odds ratios and relative risks ranged between 1.217 and 1.452 and between 1.078 and 1.175, indicating a significant positive association between these two factors. These findings suggest that deforestation notably increases snakebite risk; collectively, our findings can help develop targeted preventive measures and healthcare strategies to reduce snakebite risk globally. Full article