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Simple Summary: Using data from the Korean National Health Insurance Service—National Sample Cohort database, we evaluated whether patient-specific factors such as age, sex, income, residence, and the presence of comorbidities influence the relationship between gastric cancer (GC) and the likelihood of developing osteoporosis. Our study, with 1:4 propensity score matching and a stratified Cox proportional hazards model, showed that the hazard ratio of osteoporosis for the GC group was 1.13 (95%CI, 1.03–1.24) compared to that for the control group. In addition, subgroup analysis showed that age < 65 years, male sex, and a Charlson Comorbidity Index of 0 were risk factors for osteoporosis. Gastric cancer (GC) survivors may be more likely to develop osteoporosis. However, few studies on the relationship between GC and osteoporosis have been conducted on large patient populations. We aimed to determine the incidence of osteoporosis and identify related factors by comparing patients with GC and matched controls using the Korean National Health Insurance Service—National Sample Cohort (KNHIS-NSC). This study included 9078 patients with GC and 36,312 controls (1:4 propensity score-matched for sex, age, residence, and income). The hazard ratio (HR) for osteoporosis was significantly greater for GC patients than for controls according to Charlson Comorbidity Index (CCI) score-adjusted models (adjusted HR = 1.13). Kaplan–Meier analysis revealed that the cumulative incidence of osteoporosis during the follow-up period commencing from the index date was significantly greater in GC patients than in the controls (p = 0.0087). A positive correlation of osteoporosis with GC was detected for those aged < 65 years, males, and those with CCI scores = 0. In conclusion, the study findings suggest that men with GC aged < 65 years may be at an increased risk for osteoporosis. Research into additional risk factors and the optimal timing of interventions are needed to prevent fractures and minimize bone loss in GC survivors. [ABSTRACT FROM AUTHOR]

Objective: Previous studies have reported controversial results on the association between gout and the risk of cancer. This study aimed to investigate the relationship between gout and the incidence of head and neck cancer (HNC). Methods: The data of participants who underwent health checkups in 2009 were analyzed using the National Health Insurance Database in South Korea. A total of 14,348 HNC patients and 57,392 control participants were analyzed for a prior history of gout. Overlap weighting was applied, and odds ratios (ORs) of gout for HNC patients were analyzed. The overlap-weighted model adjusted for demographic, socioeconomic, and lifestyle factors and comorbidities. HNC sites were classified as oral cavity cancer, oropharyngeal cancer, nasopharyngeal cancer, hypopharyngeal cancer, nasal cavity/sinus cancer, larynx cancer, or salivary gland cancer, and the ORs of gout were estimated for each site. Results: Overall, patients with HNC had 1.12-fold greater odds of having gout (95% confidence intervals [CIs] = 1.04–1.20). According to the site of HNC, oral cavity cancer, oropharynx cancer, and larynx cancer demonstrated high odds of having gout (OR = 1.25, 95% CI = 1.16–1.34 for oral cavity cancer; OR = 1.08, 95% CI = 1.01–1.15 for oropharynx cancer; and OR = 1.12, 95% CI = 1.06–1.20 for larynx cancer). On the other hand, nasal cavity/sinus cancer, nasopharynx cancer, and salivary gland cancer presented low odds of having gout (OR = 0.78, 95% CI = 0.72–0.84 for nasal cavity/sinus cancer; OR = 0.89, 95% CI = 0.83–0.96 for nasopharynx cancer; and OR = 0.88, 95% CI = 0.81–0.96 for salivary gland cancer). Conclusions: A prior history of gout was associated with a high overall incidence of HNC. Oral cavity cancer, oropharynx cancer, and larynx cancer have a high incidence in gout patients. However, nasal cavity/sinus cancer, nasopharyngeal cancer, and salivary gland cancer have low incidences in gout patients. The impact of gout on HNC risk should be specifically considered according to the site of the HNC. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the changes in physical activity levels and the rate of falls during the COVID-19 pandemic in the Korean population. The Korean Community Health Survey (KCHS) conducted in 2019 was compared with that conducted in 2020. Simple or multiple linear regression with complex sampling was conducted to calculate the estimated value (EV) of physical activity in the 2020 group vs. the 2019 group. The odds ratio (OR) of fall histories was calculated using simple or multiple logistic regression with complex sampling for the 2020 group compared to the 2019 group. The time spent on vigorous and moderate physical activity was lower in the 2020 group than in the 2019 group (EV = −10.0, 95% CI = −12.1 to −8.0, P < 0.001 for vigorous exercise and EV = −24.0, 95% CI = −26.7 to −21.4, P < 0.001 for moderate exercise). The rate of falls was lower in the 2020 group than in the 2019 group (OR = 0.66, 95% CI = 0.62 to 0.70, P < 0.001). Vigorous and moderate exercise decreased after the COVID-19 pandemic compared to before the pandemic. The occurrence of falls was lower during the COVID-19 pandemic than in the pre-pandemic period. [ABSTRACT FROM AUTHOR]

Simple Summary: We conducted a study using the Korean National Health Insurance Service–National Sample Cohort database to investigate if a hazard connection existed between prior use of proton pump inhibitors (PPIs) and the development of colorectal cancer (CRC) in the Korean population. Our research, which employed a nested case–control study with a statistical technique known as "propensity score nested weighted multivariate logistic regression", revealed that the risk of developing CRC increased regardless of whether individuals had a history of PPI use or the duration of PPI use. This suggests that prior use of PPIs, whether currently or in the past, and regardless of the duration, may be linked to an increased likelihood of CRC within the Korean population, highlighting the need for cautious and precise adherence to PPI medications according to treatment guidelines to mitigate potential adverse effects. The potential connection between proton pump inhibitors (PPIs) and colorectal cancer (CRC) risk remains unclear, with specific ethnic genetic backgrounds playing a role in PPI-induced adverse effects. In this nested case–control study, we investigated the risk of CRC in relation to preceding PPI use and the duration of use using data from the Korean National Health Insurance Service–National Sample Cohort database, including 9374 incident CRC patients and 37,496 controls. To assess the impact of preceding PPI exposure (past vs. current) and use duration (days: <30, 30–90, and ≥90) on incident CRC, we conducted propensity score overlap-weighted multivariate logistic regression analyses, adjusted for confounding factors. Our findings revealed that past and current PPI users had an increased likelihood of developing CRC. Regardless of duration, individuals who used PPIs also had higher odds of developing CRC. Subgroup analyses revealed that CRC occurrence increased independent of history or duration of prior PPI use, consistent across various factors such as age, sex, income level, and residential area. These findings suggest that PPI use, regardless of past or present use and duration of use, may be related to an increased risk of developing CRC in the Korean population. [ABSTRACT FROM AUTHOR]

Simple Summary: Using Korean National Health Insurance Service-National Sample Cohort database, we studied whether patient-specific factors such as age, gender, socioeconomic status, and presence of comorbidities may influence the relationship between gout and the likelihood of developing CRC. Our nested case-control study with propensity score overlap-weighted multivariate logistic regression analyses suggest that patients with gout are not at higher risk for CRC than a control group, indicating that gout may not significantly and independently contribute to the CRC risk of the general population. Nevertheless, within a specific subgroup of patients aged less than 65 years, there appeared to be a moderately reduced probability of CRC development. Further comprehensive research is necessary to substantiate this association and gain a better understanding of the underlying causal factors. Considering the global importance of both gout and colorectal cancer (CRC) as significant health issues with mutual relevance, we aimed to examine the risk of colorectal cancer in Korean patients with gout. In this nested case-control study, we used data from 9920 CRC patients and 39,680 controls the Korean National Health Insurance Service-National Sample Cohort database. Propensity score overlap-weighted multivariate logistic regression analyses, adjusted for confounders, were used to assess the odds ratio (OR) and 95% confidence interval (CI) of the association between gout and CRC. Adjusted OR for CRC were similar between patients with gout and the control group (0.95; 95% CI, 0.86–1.04; p = 0.282). However, after adjustment, subgroup analysis revealed an 18% reduction in the probability of CRC among patients younger than 65 years with gout (95% CI, 0.70–0.95; p = 0.009). Conversely, absence of an association between gout and subsequent CRC persisted regardless of sex, income, residence, and Charlson Comorbidity Index score, even among individuals aged 65 years or older. These results imply that gout may not be a significant independent risk factor for CRC among the general population. However, in patients younger than 65 years with gout, a slightly reduced likelihood of CRC was observed. Further research is necessary to establish a causal relationship between gout and CRC and to generalize these findings to other populations. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigates the potential link between Alzheimer's disease (AD) and the probability of developing various cancers using a large cohort dataset in Korea from matching 24,664 Korean citizens with AD and without a history of cancer with 98,656 non-AD and noncancer Korean citizens. The results revealed that patients with AD had a significantly lower likelihood of developing overall malignancy as well as specific types of cancer compared to the control group. Notably, pancreatic cancer showed the strongest inverse relationship with AD. The protective effect against certain organ-specific cancers persisted throughout the 16-year follow-up period, particularly in individuals aged 60 years and above. These findings suggest that Korean patients with AD may have a decreased risk of malignancy, highlighting the need to explore the connection between AD and cancer risk. The link between Alzheimer's disease and cancer risk is a concern in public health. However, research has yielded limited and sometimes contrasting results, suggesting the need for more validation. We analyzed a large cohort to examine the long-term association between Alzheimer's disease (AD) and the risk of developing cancer. In total, 24,664 AD patients and 98,656 control participants were selected from the National Health Insurance Cohort database of Korea, spanning from 2002 to 2019. Propensity score matching and overlap-weighted adjustment techniques were used to balance the standardized differences between the AD and control groups. The Cox proportional hazards model was applied to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for various cancers, considering relevant covariates. Results indicated that patients with AD had a significantly lower likelihood of overall malignancy (HR 0.63; 95% CI, 0.59–0.68) and each of the 10 site-specific cancers compared to the control group. Among these, pancreatic cancer (HR, 0.50) exhibited the strongest inverse association, followed by hepatic (HR, 0.60), gastric (HR, 0.63), kidney (HR, 0.63), lung (HR, 0.64), thyroid (HR, 0.65), colorectal (HR, 0.67), gallbladder and biliary duct (HR, 0.73), hematologic malignancy (HR, 0.73), and bladder cancers (HR, 0.76). This protective effect against certain organ-specific cancers persisted over the 16-year follow-up period, except for in kidney cancer and hematologic malignancies. The protective effect against specific cancer types (gastric, colorectal, lung, hepatic, and pancreatic) was more prominent in individuals aged 60 years and older, regardless of their sex. However, there were some variations in the specific types of cancer observed between males and females. In summary, Korean patients with AD had a lower risk of cancer, especially in individuals 60 years and older, during the 16-year follow-up period. [ABSTRACT FROM AUTHOR]

Simple Summary: This research investigates the potential link between gum disease and stomach cancer in the Korean population. In this study, we analyzed data from over 10,000 people with gastric cancer and 40,000 healthy individuals. The results indicate that individuals who had gum disease in the past one to two years were more likely to develop stomach cancer. This association was consistently observed in different groups, such as men under 65 years old. The study emphasizes the importance of regular screening for stomach cancer, particularly for those at high risk, such as individuals with a history of gum disease. These findings contribute to our understanding of the connection between oral health and stomach cancer and may guide future preventive measures. There is limited information regarding the potential association between chronic periodontitis (CP) and gastric cancer, especially in the Korean population. This study aimed to explore this relationship. This nested case–control study analyzed data from 10,174 patients with gastric cancer and 40,696 controls from the Korean National Health Insurance Service–National Sample Cohort using propensity score matching. Standardized differences were used to compare baseline characteristics between study groups. Logistic regression analyses adjusted for confounders were conducted to assess the association between history of CP and gastric cancer occurrence. CP histories and comprehensive subgroup analyses in the 1- and 2-year periods preceding the index date were evaluated. Individuals with a history of CP within the 1-year and 2-year periods showed an increased likelihood of developing gastric cancer. Subgroup analyses consistently supported these findings in male participants aged <65 years and individuals with various income levels or living in residential areas. However, no significant associations were observed among participants aged ≥65 years. In conclusion, CP may be a potential risk factor for gastric cancer development in the Korean population. Regular screening for gastric cancer may be necessary for high-risk individuals, specifically men aged <65 years with a history of CP. [ABSTRACT FROM AUTHOR]

Background: Whether migraine is related to the risk of cardiovascular diseases (CVDs) remains unclear. Therefore, we conducted a longitudinal follow-up study to address the association between migraine and the development of CVDs in Korea. Methods: Using data from the national health screening cohort, we included 45,246 patients diagnosed with migraine between 2002 and 2019 and age-, sex-, income-, and residential region-matched nonmigraine participants at a ratio of 1:4. Participants with previous CVDs were excluded. Cox proportional hazards regression models were used to estimate the hazard ratios of three CVDs, stroke, ischemic heart disease, and heart failure, in patients with migraine after adjusting for potential cardiovascular risk factors. Results: The incidence rate differences of stroke, ischemic heart disease, and heart failure among patients with migraine were 2.61, 1.69, and 0.11, respectively. The probability of developing stroke and ischemic heart disease in patients with migraine was significantly higher than that in controls after controlling for multiple confounders (adjusted hazard ratio [HR] = 1.35, 95% confidence interval [CI] = 1.31–1.39 and adjusted HR = 1.31, 95% CI = 1.26–1.35, respectively). However, when compared with the patients without migraine, patients with migraine did not have an increased HR of developing heart failure (adjusted HR = 1.01, 95% CI = 0.95–1.08). The overall migraine group, as well as groups stratified by migraine subtypes with and without aura, each showed a significantly higher probability of subsequent stroke and ischemic heart disease than the control group. Conclusions: Our longitudinal follow-up study demonstrated a significant association between the presence of migraine and the development of stroke and ischemic heart disease in Korea, even after adjusting for cardiovascular risk factors. [ABSTRACT FROM AUTHOR]

Background: During the coronavirus disease (COVID-19) pandemic, the amount of moderate- to high-intensity physical activity significantly decreased. Therefore, the epidemiology of musculoskeletal diseases could possibly have changed. We assessed changes in the incidence of and variance in non-traumatic orthopedic diseases before and after the COVID-19 pandemic in Korea. Methods: This study included data from the Korea National Health Insurance Service, which covers the entire Korean population (approximately 50 million), from January 2018 to June 2021. Using International Classification of Diseases, Tenth Revision codes, 12 common orthopedic diseases were evaluated, including cervical disc disorders, lumbar disc disorders, forward head posture, myofascial pain syndrome, carpal tunnel syndrome, tennis elbow, frozen shoulder, rheumatoid arthritis, gout, hip fracture, distal radius fracture, and spine fracture diseases. "Pre-COVID-19" was the period until February 2020, and "COVID-19 pandemic period" was the period starting March 2020. Differences in the mean incidence and variance of diseases before and during the COVID-19 pandemic were compared. Results: In most cases, the incidence of orthopedic diseases decreased at the beginning of the pandemic and then increased thereafter. Among the 12 diseases, the incidence of three diseases showed a statistically significant change. The incidence of myofascial pain syndrome (P < 0.001) was lower during the COVID-19 pandemic than during the pre-COVID-19 period. The incidences of frozen shoulder (P < 0.001) and gout (P = 0.043) were higher during the COVID-19 pandemic than during the pre-COVID-19 period. However, no statistical difference in disease variations was observed between the two periods. Conclusions: The incidence of orthopedic diseases varied during the COVID-19 pandemic among the Korean population. Although the incidence of myofascial pain syndrome was lower, that of frozen shoulder and gout was higher during the COVID-19 pandemic than during the pre-COVID-19 period. No disease variations during the COVID-19 pandemic were found. [ABSTRACT FROM AUTHOR]

A connection between asthma and the occurrence of Parkinson's disease (PD) has been suggested, but the findings have been contentious and require verification. In this nested case–control study using data from the Korean National Health Insurance Service—Health Screening Cohort (2002–2019), which comprised 9029 participants with PD and 36,116 matched controls, we explored the relationship between asthma and incident PD. An overlap-weighted logistic regression model was used to measure the probability of asthma and PD. After adjusting for various covariates, we found that asthma was related to a 1.11-fold greater probability of PD (95% confidence interval: 1.06–1.16). A subgroup analysis showed that this effect was independent of age, sex, residential area, or alcohol consumption, and that it was still noticeable even among patients with a high income; those with a normal weight or obesity; those who were non-smokers or current smokers; and those with no history of chronic obstructive pulmonary disease, hypertension, hyperglycemia, hyperlipidemia, or anemia. Thus, these findings may indicate that asthma may slightly augment the likelihood of PD in the Korean adult population regardless of demographic or lifestyle factors, making it difficult to predict PD in asthma patients. [ABSTRACT FROM AUTHOR]

The correlation between statin use and the development of gallstone disease remains controversial. Existing data, primarily based on Caucasian populations, are biased, thus necessitating validation studies involving Asian cohorts. We conducted a nested case–control study using data from the Korean National Health Insurance Service Health Screening Cohort (2002–2019) to determine the likelihood of gallstone disease according to periods of previous statin use and type of statin. Among the 514,866 participants, 22,636 diagnosed with gallstones at ≥2 clinic visits (using the International Classification of Diseases, 10th revision, code K80) were matched 1:4 to 90,544 controls for age, sex, income, and residential area, and their statin prescription history for 2 years prior to the index date was examined. Propensity-score-weighted odds ratios (ORs) for gallstone disease were calculated using conditional logistic regression. Long-term use (>545 days) of any statin or lipophilic statins was associated with lower odds of incident gallstones (OR = 0.91, 95% confidence interval [CI] = 0.86–0.96, p < 0.001 and OR = 0.88, 95% CI = 0.83–0.93, p < 0.001, respectively) after adjusting for confounders. Short-term use (180–545 days) of any statin or hydrophilic statins was not statistically related to incident gallstones. In summary, prior statin medication, particularly long-term lipophilic statin use, may confer a preventive advantage against gallstone disease. [ABSTRACT FROM AUTHOR]

To date, no clear conclusion on the relationships of gout with the occurrence of typical neurodegenerative diseases, Alzheimer's disease (AD) and Parkinson's disease (PD), has been reached. This study aimed to determine whether the patients with gout are at a lower or higher probability of developing AD or PD than those without gout. Longitudinal follow-up data of a representative sample of Korean adults were assessed. 18,079 individuals diagnosed with gout between 2003 and 2015 were enrolled in the gout group. The comparison group comprised 72,316 demographics-matched individuals not diagnosed with gout. Longitudinal associations of gout with AD or PD were estimated using Cox proportional hazard regression adjusting for potential confounders. The adjusted hazard ratios (HRs) of AD and PD in the gout group were 1.01 and 1.16 times higher than controls, but these differences were not statistically significant (95% confidence interval [CI] = 0.92–1.12 and 95% CI = 0.97–1.38, respectively). Although there was no significant association in the entire sample, AD and PD probabilities in patients with gout were significantly higher in participants < 60 years, and PD probabilities in patients with gout were significantly higher in overweight participants. Our findings identify significant correlations of gout with AD and PD in participants < 60 years and gout with PD in those with overweight, indicating that gout may play a role in the development of neurodegenerative diseases in younger or overweight populations. Further investigations should be performed to corroborate these findings. [ABSTRACT FROM AUTHOR]

This study undertook to determine the changes in the numbers of outpatient visits for various ophthalmic diseases during the COVID-19 pandemic compared with before. The monthly outpatient visits for 14 common ophthalmic diseases were enumerated based on the ICD-10 codes in Korean National Health Insurance Service data. The differences in the mean outpatient visits and disease variance 'before' and 'during COVID-19' were calculated. Subsequently, subgroup analyses according to age and sex were performed. The number of outpatient visits for conjunctivitis, scleritis & episcleritis, keratitis, cataract, diabetic retinopathy, and traumatic ophthalmic disease were lower during than before COVID-19 (all P < 0.001). The lower numbers of outpatient visits for ophthalmic disorders during COVID-19 were consistent across the age and sex subgroups. All ophthalmic diseases other than endophthalmitis showed no change of variation 'during' relative to 'before' COVID-19. In conclusion, during the COVID-19 pandemic, the ophthalmic outpatient visits decreased for infectious and inflammatory diseases, screening diseases, and traumatic diseases. However, COVID-19 is not considered to have had a significant effect on variation. [ABSTRACT FROM AUTHOR]

A few retrospective studies have suggested the risk of urolithiasis associated with the use of proton pump inhibitors (PPIs). The current research intended to estimate the risk of urolithiasis according to previous PPI use. A nested case-control study was conducted using the National Health Insurance Service-National Health Screening Cohort in Korea. A total of 28,962 patients with urolithiasis and 115,848 control participants were selected. The previous prescription history of PPI with days of PPI prescription was collected. To calculate the odds ratios (OR) of past, current, and days of PPI use for urolithiasis, logistic regression models were used. Subgroup analyses were conducted. The urolithiasis group demonstrated a higher rate of current PPI users than the control group (60.9% vs. 43.7%). The current PPI users indicated 2.49 times higher odds for urolithiasis than no PPI users (95% confidence intervals [CI] = 2.33–2.66). A longer duration of PPI use was associated with greater odds for urolithiasis (adjusted OR = 1.65 (95% CI = 1.54–1.77) < 1.97 (95% CI = 1.84–2.11) < 2.32 (95% CI = 2.14–2.49) for 1–19 days, 30–364 days, and 365 or more days of PPI prescription). All subgroup analyses described a consistently positive association of previous PPI use with urolithiasis. Prior PPI use was related to a higher risk of urolithiasis. The relationship between previous PPI use and urolithiasis demonstrated a dose-response association. [ABSTRACT FROM AUTHOR]

Background: Identifying the risk factors for falls among the elderly population is arguably one of the most imperative public health issues in the current aging society. Objectives: This study aimed to determine the associations between depressive symptoms, subjective cognitive decline (SCD), and poor subjective sleep quality and the risk of slips/falls in a Korean older population. Methods: This cross-sectional study involved 228,340 elderly individuals living in Korea. Measurements included self-reported depressive symptoms, SCD, and self-reported sleep quality. The risk of slips/falls was dichotomized depending on whether slips/falls had occurred during the past year, and the associations between different risk factors and slips/falls were explored. Multiple logistic regression was used to obtain the odds ratios (ORs) and 95% confidence intervals (CIs). Complex sampling methods were used to estimate the weighted value of each participant. Results: The risk of slips/falls was significantly associated with high levels of depressive symptoms (adjusted OR 1.06, 95% CI: 1.05–1.07) and SCD (adjusted OR 1.33, 95% CI: 1.19–1.50). Regarding each sleep quality component, the adjusted ORs for slips/falls were 1.85 for very poor sleep quality, 1.49 for long sleep latency, 1.04 for <5 h of sleep duration, 1.32 for low sleep efficiency, 2.78 for high sleep disturbance, 1.52 for the use of sleep medication ≥3 times a week, and 1.82 for high daytime dysfunction due to sleep problems compared to the respective good sleep conditions. Conclusions: Our results demonstrated that depressive symptoms, SCD, and poor subjective sleep quality are independent factors affecting the occurrence of slips/falls. Thus, efforts to manage depressive symptoms and cognitive decline early and to improve sleep quality can be an alternative strategy to decrease the likelihood of falls. [ABSTRACT FROM AUTHOR]

The implementation of precautionary measures, such as wearing a mask and social distancing, may have affected allergic diseases during the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to compare the numbers of medical visits for allergic diseases before and during the COVID-19 pandemic. Data were obtained from the Korean National Health Insurance claims database. Monthly numbers of patients for four allergic diseases, i.e., allergic rhinitis (AR), asthma, atopic dermatitis (AD), and allergic conjunctivitis (AC), were evaluated using ICD-10 codes and compared between the 'before COVID-19' period from January 2018 to February 2020, and the 'during COVID-19' period from March 2020 to June 2021, since the first COVID-19 patient was detected on 20 January 2020, in Korea. Subgroup analyses were performed according to age and sex. The mean numbers of medical visits for AR and asthma were significantly greater before COVID-19 than those during COVID-19 (both p < 0.001). The variance in the number of medical visits for asthma decreased during the COVID-19 pandemic. However, the mean number of medical visits for AD increased slightly during COVID-19 and that for AC did not change before and during the COVID-19 pandemic. In subgroup analyses, the results showed a similar pattern to that of the total number of participants, regardless of age and sex. In conclusion, medical visits for AR and asthma significantly decreased during the COVID-19 pandemic, regardless of age and sex. [ABSTRACT FROM AUTHOR]

Foreign bodies (FBs) in the nasal cavity are commonly encountered in otorhinolaryngology. This retrospective study was conducted between January 2009 and December 2020. The nasal FB frequencies were investigated according to age and sex. The type, shape, and location of the FBs, onset, and clinical features were obtained. In a total of 1228 cases, the average age was 3.9 ± 5.7 years. We found a higher incidence in patients 2–4 years old. The most frequent nasal FBs were beads (24.0%), toys/plastics (17.8%), and beans/corn (15.8%). However, there were some differences in the nasal FB types according to the age group. There was no difference in the location of the nasal FBs according to age group, but nasal FBs were found more frequently in the right nasal cavity in the 1–3-years-old groups. Most patients (97.5%) visited the hospital the same day when the nasal FB insertion was suspected, and most were asymptomatic. After the removal of the nasal FBs, most patients were free of complications. Of the nine cases involving button batteries, septal perforation was observed in two patients who visited the hospital one or two days after the FB insertion. There were specific age-based characteristics of the nasal FBs that may serve as a basis for specific precautions. [ABSTRACT FROM AUTHOR]

There is scarcity in the evidence addressing the indirect impact of the COVID-19 pandemic on the epidemiology of CVDs. In this study we aimed to examine possible changes in the incidence of CVDs in Korea during the COVID-19 pandemic. ICD-10 codes of six common CVDs (cerebral hemorrhage, cerebral infarction, myocardial infarction, ischemic heart disease, cardiac failure, and arrhythmia) were collected from clinical visits between January 2018 and March 2021 using the National Health Insurance service database, which stores data on all citizens of Korea (~50 million people). The number and distribution of monthly visits for CVDs were compared before and during the COVID-19 pandemic, and the differences were analyzed using the Mann–Whitney U test and Levene's test. Our data showed similar incidences of cerebral hemorrhage and ischemic heart disease, a lower incidence of cerebral infarction, and higher incidences of myocardial infarction, cardiac failure, and arrhythmia during COVID-19. Despite statistical differences, the changes in incidences were not considered meaningful. The monthly incidences also remained similar throughout the year, without seasonal variations, both before and during the COVID-19 outbreak. This study found no significant changes in the incidences or monthly variation in CVDs due to the COVID-19 pandemic in Korea. [ABSTRACT FROM AUTHOR]

We investigated whether the coronavirus disease 2019 (COVID-19) pandemic, in conjunction with public health measures, influenced the incidence of gastrointestinal diseases according to age and sex during the pandemic. Changes in the monthly incidence rates (January 2018 to June 2021) of common gastrointestinal diseases were assessed using data from the Korean National Health Insurance Service by comparing the data of two periods: before COVID-19 (January 2018–February 2020) and during COVID-19 (March 2020–June 2021). The Mann–Whitney U test and Levene's test were used to compare the differences in the incidences before and during the pandemic. In the pandemic period, compared to in the pre-COVID-19 period, the incidence rates of ulcerative colitis, Crohn's disease, cholelithiasis, and esophageal reflux significantly increased, whereas those of infective enteritis and irritable bowel syndrome decreased, regardless of age or sex. There were no significant changes in the incidence rates of pancreatitis, acute appendicitis, liver cirrhosis, and hemorrhoids. No seasonal variations in gastrointestinal disease occurrence were observed. In conclusion, the COVID-19 pandemic may have had unprecedented and long-term impacts on the epidemiology of gastrointestinal disease. These changes may indicate a substantial future burden on healthcare resources during the recovery phase of the pandemic and thereafter. [ABSTRACT FROM AUTHOR]

Objectives: The relationship between smoking and subjective cognitive decline (SCD), which is defined as the subjective perception of cognitive decline, is not well known. This study aimed to investigate the relationship of various types of smoking, including E-cigarette smoking and the use of E-liquid, with the incidence of SCD among Korean adults. Methods: We evaluated the 2018 Korean Community Health Survey data collected from community-dwelling people in Korea. A total of 104,453 non-smokers, 38,607 past smokers, and 26,776 current smokers with eligible data were included in the study. SCD was assessed using the Behavioral Risk Factor Surveillance System. The past or current smoking pack-years throughout each participant's entire life were calculated. Multiple regression analyses were carried out to estimate the adjusted odds ratios (ORs) as measures of the association between each type of smoking and SCD after adjustment for potential confounders. Results: Compared to no exposure, passive smoking was associated with higher odds of SCD. Compared to non-smokers, past smokers had a higher OR for SCD; however, current smokers did not. There were no significant associations between passive smoking and SCD in the non-smoker and past smoker groups, but there was a significant relationship between them in the current smoker group. While the cumulative dose of smoking was correlated with an increased OR of SCD in each group of current smokers and past smokers, E-cigarette smoking and the use of E-liquid were not associated with higher ORs in the current smoker group. Conclusion: Our findings support that passive smoking and past smoking are significantly associated with SCD and that more cumulative exposure to smoking is correlated with a higher OR of SCD. [ABSTRACT FROM AUTHOR]

The prevalence of neurodegenerative dementia is increasing owing to the rapid growth of the older population. We investigated risks and causes of mortality in Korean patients with neurodegenerative dementia using data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort with the aim to improve their care. From a pool of 1,125,691 patients, 11,215 patients aged ≥60 years who were diagnosed with dementia between 2002 and 2013 were examined along with 44,860 matched controls. A Cox proportional hazard model was used to calculate crude and adjusted hazard ratios (HRs). During the follow-up period, 34.5% and 18.8% of individuals in the neurodegenerative dementia and control groups, respectively, died (P < 0.001). The adjusted HR for mortality in the neurodegenerative dementia group was 2.11 (2.41 and 1.96 in men and women, respectively). Moreover, the adjusted HRs in patients with neurodegenerative dementia were 3.25, 2.77, and 1.84 for those diagnosed at ages 60–69, 70–79, and ≥80 years, respectively. The highest odds ratio for mortality was noted among patients with neurologic disease (15.93) followed by those with mental disease (4.89). These data show that the risk of mortality increased regardless of age and sex in Korean patients with neurodegenerative dementia. [ABSTRACT FROM AUTHOR]

The association between lipid levels and uric acid disorders remains controversial. We evaluated the association between dyslipidemia and gout in a large cohort from the Korean National Health Insurance Service-Health Screening Cohort. Among the 514,866 participants aged ≥40 years, 16,679 gout participants were selected and matched with 66,716 control participants for income, region of residence, sex, and age. We used the ICD-10 codes to define dyslipidemia (E78) and gout (M10) and diagnosis was confirmed when each was reported ≥2 times. The odds ratios (ORs) of dyslipidemia history were calculated using conditional logistic regression in crude, partial, and fully adjusted models. The days of statin use, systolic and diastolic blood pressure, fasting glucose level, total cholesterol, obesity, Charlson comorbidity index, alcohol consumption, and smoking were used as covariates. Patients with gout had a significantly higher dyslipidemia history than those without gout (33.1% vs. 24.0%, p < 0.001). The association was significant after adjustment (OR in partial adjusted model = 1.50, 95% confidence interval (CI) = 1.44–1.57; OR in fully adjusted model = 1.43, 95% CI = 1.37–1.49). These findings were consistent with the subgroup analysis. Our findings suggest that dyslipidemia history is more likely in patients with gout aged ≥40 years than in healthy controls among Korean population. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has been suggested to have adverse impacts on psychiatric disorders. This study aimed to investigate the changes in medical visits due to a wide range of psychiatric disorders in children during the COVID-19 pandemic. The medical visits of all Korean children and adolescents (0–19 years old) due to the 12 following psychiatric disorders were investigated: autism; attention-deficit/hyperactivity disorder (ADHD); depressive disorder; bipolar disorder; primary insomnia; schizophrenia; panic disorder; hypochondriasis; posttraumatic stress disorder (PTSD); anxiety disorder; anorexia nervosa; and adephagia. The mean medical visits before and during the COVID-19 pandemic were compared. The mean number of clinical visits due to autism, ADHD, depressive disorder, bipolar disorder, panic disorder, hypochondriasis, PTSD, anxiety disorder, and anorexia nervosa was higher during the COVID-19 pandemic than before the COVID-19 pandemic (all p < 0.05). The higher mean number of medical visits due to psychiatric disorders was maintained in age and sex subgroups. The female and adolescent groups demonstrated a higher mean number of medical visits due to psychiatric disorders during the COVID-19 pandemic. The medical visits due to many psychiatric disorders were higher during the COVID-19 pandemic than before COVID-19 in children and adolescents in Korea. Women and adolescents were more susceptible to psychiatric disorders during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID-19) pandemic has been suggested to increase the risk of depression and anxiety disorders. This study expanded upon previous findings by estimating the changes in medical visits for various psychological disorders during the COVID-19 pandemic compared to before COVID-19. The entire Korean population ≥ 20 years old (~42.3 million) was included. The first COVID-19 case in Korea was reported on 20 January 2020. Thus, the period from January 2018 through to February 2020 was classified as "before COVID-19", and the period from March 2020 through to May 2021 was classified as "during COVID-19". Monthly medical visits due to the following 13 psychological disorders were evaluated: depressive disorder, bipolar disorder, primary insomnia, schizophrenia, panic disorder, hypochondriasis, posttraumatic stress disorder (PTSD), anxiety disorder, anorexia nervosa, addephagia, alcoholism, nicotine dependency, and gambling addiction were evaluated. The differences in the number of medical visits and the variance of diseases before and during the COVID-19 pandemic were analyzed using the Mann–Whitney U test and Levene's test. Subgroup analyses were conducted according to age and sex. The frequencies of medical visits for depressive disorder, bipolar disorder, primary insomnia, panic disorder, hypochondriasis, PTSD, anxiety disorder, anorexia nervosa, addephagia, and gambling addiction were higher during COVID-19 than before COVID-19 (all p < 0.001). However, the frequencies of medical visits for schizophrenia, alcoholism, and nicotine dependency were lower during the COVID-19 pandemic than before the COVID-19 pandemic (all p < 0.001). The psychological disorders with a higher frequency of medical visits during COVID-19 were consistent in all age and sex subgroups. In the old age group, the number of medical visits due to schizophrenia was also higher during COVID-19 than before COVID-19 (p < 0.001). Many psychological disorders, including depressive disorder, bipolar disorder, primary insomnia, panic disorder, hypochondriasis, PTSD, anxiety disorder, anorexia nervosa, addephagia, and gambling addiction, had a higher number of related medical visits, while disorders such as schizophrenia, alcoholism, and nicotine dependency had a lower number of related medical visits during COVID-19 among Korean adults. [ABSTRACT FROM AUTHOR]

Safety issues regarding the potential risk of statins and incident rheumatoid arthritis (RA) have been raised, but the existing data are largely based on Caucasian populations, and continue to have biases and require further validation in Asian populations. Here, we aimed to verify the risk of RA depending on the duration of previous statin use and statin types using a large-scale, nationwide database. This study enrolled 3149 patients with RA and 12,596 matched non-RA participants from the national health insurance database (2002–2015), and investigated their statin prescription histories for two years before the index date. Propensity score overlap-weighted logistic regression was applied after adjusting for multiple covariates. The prior use of any statins and, specifically, the long-term use of lipophilic statins (>365 days) were related to a lower likelihood of developing RA ((odds ratio (OR) = 0.73; 95% confidence intervals (CI) = 0.63–0.85, p < 0.001) and (OR = 0.71; 95% CI = 0.61–0.84, p < 0.001), respectively). Subgroup analyses supported these preventive effects on RA in those with dyslipidemia, independent of sex, age, smoking, alcohol use, hypertension, and hyperglycemia. Hydrophilic statin use or short-term use showed no such associations. Our study suggests that prior statin use, especially long-term lipophilic statin use, appears to confer preventive benefits against RA. [ABSTRACT FROM AUTHOR]

Objectives: Thyroid dysfunction is linked to an increased risk of cognitive impairment. However, studies on the relationships between thyroid diseases and Alzheimer's disease (AD) have reported conflicting results. We investigated the associations between several thyroid diseases and AD in a nested case-control study. Methods: A total of 1,977 participants with AD were identified by claims data from 2002-2015 among a random sample of half a million people in the Korean National Health Insurance database. We recruited 16,473 age- and sex-matched (1:4 ratio) control participants and applied conditional logistic regression to estimate the relationships between thyroid diseases and AD, with adjustments for potential confounders, such as basic demographics, lifestyle factors, and various medical conditions or comorbidities. Results: The prevalence rates of hypothyroidism (odds ratio [OR]=1.14, 95% confidence interval [CI]=1.00-1.30), thyroiditis (OR=1.22, 95% CI=1.05-1.40), and hyperthyroidism (OR=1.13, 95% CI=1.01-1.28) were significantly higher in participants with AD than in control participants after adjustment for confounders. Conclusion: In this large national sample, we found significant relationships between several thyroid diseases and AD. Despite of the need for further investigation, these findings could better support to appreciate the pathophysiology of AD. [ABSTRACT FROM AUTHOR]

Objective: Hysterectomy is one of the most commonly performed gynecological procedures. Several studies have reported an association between hysterectomy and coronary heart disease (CHD), but the conclusions are controversial. This study aimed to evaluate the association between hysterectomy and the occurrence of CHD using a national sample cohort from South Korea.Study Design: Using the national cohort from the Korean National Health Insurance Service, we extracted data on patients who had undergone hysterectomy (n = 8,642) and on controls matched at a ratio of 1:4 (n = 34,568) and then analyzed the occurrence of CHD from 2002 to 2013. Patients were matched according to age, income, region of residence, obesity, smoking, alcohol consumption, and medical history.Main Outcome Measures: A Cox proportional hazards model was used to analyze the hazard ratios (HRs) and 95% confidence intervals (CIs). Subgroup analyses were performed based on both age and bilateral salpingo-oophorectomy (BSO) status. The age of the participants was defined as that at the time of hysterectomy.Results: The HR for CHD was 1.05 (95% CI = 0.96-1.16, p = 0.286) in the hysterectomy group. The HRs for CHD according to the different age subgroups were 1.19 (95% CI = 1.03-1.38, p = 0.018) for patients aged < 50 years, 1.05 (95% CI = 0.89-1.25, p = 0.561) for patients aged 50-59 years, and 0.88 (95% CI = 0.73-1.05, p = 0.147) for patients aged ≥ 60 years.Conclusion: The incidence of CHD was statistically significantly higher in women who underwent hysterectomy when they were under 50 years of age than in the matched controls. [ABSTRACT FROM AUTHOR]

Background : Public health concerns regarding the potential link between osteoporosis and the increased occurrence of Alzheimer's disease (AD) and Parkinson's disease (PD) have been raised, but the results remain inconsistent and require further validation. Here, we investigated the long-term relationship of osteoporosis with the occurrence of AD/PD using data from a large-scale nationwide cohort. Methods : This longitudinal follow-up study included 78,994 patients with osteoporosis and 78,994 controls from the Korean National Health Insurance Service-Health Screening Cohort database (2002–2015) who were matched using propensity score matching at a 1:1 ratio based on age, sex, income, and residential area. A Cox proportional hazard model was used to assess the association between osteoporosis and the occurrence of AD/PD after adjusting for multiple covariates. Results : During the follow-up period, AD occurred in 5,856 patients with osteoporosis and 3,761 controls (incidence rates: 10.4 and 6.8 per 1,000 person-years, respectively), and PD occurred in 1,397 patients and 790 controls (incidence rates: 2.4 and 1.4 per 1,000 person-years, respectively). The incidences of AD and PD were significantly higher in the osteoporosis group than in the matched control group. After adjustment, the osteoporosis group exhibited 1.27-fold and 1.49-fold higher occurrences of AD (95% confidence interval (CI) = 1.22–1.32) and PD (95% CI = 1.36–1.63) than the controls, respectively. The results of subgroup analyses supported the increased occurrence of AD and PD in patients with osteoporosis, independent of income, residential area, obesity, smoking, alcohol consumption, hyperlipidemia, hypertension, or blood glucose level. Conclusion : Our results indicate that the presence of osteoporosis may increase the likelihood of developing two common neurodegenerative diseases in adults aged ≥40 years. [ABSTRACT FROM AUTHOR]

We aimed to investigate the associations of previous influenza/URI with the susceptibility of COVID-19 patients compared to that of non-COVID-19 participants. A nationwide COVID-19 cohort database was collected by the Korea National Health Insurance Corporation. A total of 8,070 COVID-19 patients (1 January 2020 through 4 June 2020) were matched with 32,280 control participants. Severe COVID-19 morbidity was defined based on the treatment histories of the intensive care unit, invasive ventilation, and extracorporeal membrane oxygenation and death. The susceptibility/morbidity/mortality associated with prior histories of 1–14, 1–30, 1–90, 15–45, 15–90, and 31–90 days before COVID-19 onset were analyzed using conditional/unconditional logistic regression. Prior influenza infection was related to increased susceptibility to COVID-19 (adjusted odds ratio [95% confidence interval] = 3.07 [1.61–5.85] for 1–14 days and 1.91 [1.54–2.37] for 1–90 days). Prior URI was also associated with increased susceptibility to COVID-19 (6.95 [6.38–7.58] for 1–14 days, 4.99 [4.64–5.37] for 1–30 days, and 2.70 [2.55–2.86] for 1–90 days). COVID-19 morbidity was positively associated with influenza (3.64 [1.55–9.21] and 3.59 [1.42–9.05]) and URI (1.40 [1.11–1.78] and 1.28 [1.02–1.61]) at 1–14 days and 1–30 days, respectively. Overall, previous influenza/URI did not show an association with COVID-19 mortality. Previous influenza/URI histories were associated with increased COVID-19 susceptibility and morbidity. Our findings indicate why controlling influenza/URI is important during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Background/objectives: Few studies have evaluated the effects of energy drinks on allergic diseases. The purpose of this investigation was to evaluate the association between energy drinks and various allergic diseases, including asthma, allergic rhinitis, and atopic dermatitis, in a large representative Korean adolescent population.Subjects/methods: This cross-sectional study used data from the Korea Youth Risk Behavior Web-based Survey collected from 2015 to 2016. A total of 129,809 participants (n = 67,056 for males; n = 62,753 for females) aged 12-18 years were included and were asked about their frequency of consumption of energy drinks such as Hot6®, Redbull®, and Bacchus®. Their history of asthma, allergic rhinitis, and atopic dermatitis throughout life and in the last 12 months were obtained. The association between the frequency of energy-drink consumption and allergic diseases was analyzed using multiple logistic regression with adjustment for various covariates.Results: Age, sex, physical activity, obesity, region of residence, economic level, paternal and maternal educational level, smoking, and alcohol consumption differed significantly according to the frequency of energy-drink consumption (each P < 0.001). Frequent energy-drink consumption (≥7 times a week) was significantly associated with asthma throughout life (odds ratio [OR] = 1.30, 95% confidence interval (CI) = 1.03-1.64, P = 0.025), asthma within the last 12 months (OR = 1.65, 95% CI = 1.16-2.35, P = 0.006), allergic rhinitis within the last 12 months (OR = 1.21, 95% CI = 1.02-1.44, P = 0.030), and atopic dermatitis within the last 12 months (OR = 1.49, 95% CI = 1.17-1.90, P = 0.001) compared to no energy-drink consumption in the full-adjusted model.Conclusions: Frequent energy-drink consumption is associated with allergic diseases, including asthma, allergic rhinitis, and atopic dermatitis, in Korean adolescents. [ABSTRACT FROM AUTHOR]

Background: Chronic periodontitis is a multifactorial inflammatory disease resulting in patients exhibiting high levels of inflammatory factors causing systemic inflammatory bone destruction that may lead to osteoporosis development. The association between periodontitis and osteoporosis has been documented; however, the findings remain unclear. This study aimed to identify the association between periodontitis and osteoporosis using a cross-sectional study design and Korean Genome and Epidemiology Study (KoGES) health examinee data. Methods: This cross-sectional study used epidemiological data from the KoGES during 2004–2016. Of 125,324 participants (age, 40–79 years), 9969 with periodontitis and 115,332 controls (without periodontitis) were selected. We analyzed the history of osteoporosis and fractures of all participants. All participants were examined according to age, sex, income group, obesity, smoking habits, alcohol consumption, and food intake. To analyze the odds ratio (OR) of periodontitis for those with osteoporosis and fractures, a logistic regression model was used. Results: The adjusted odds ratio (aOR) of periodontitis for osteoporosis was 2.16 (95% confidence interval [CI], 2.01–2.31; P < 0.001). The aOR of periodontitis for any fracture was 1.54 (95% CI 1.46–1.62; P < 0.001). Conclusion: Osteoporosis and fractures are associated with periodontitis. Performing regular oral hygiene and examinations of bone mineral density are recommended to prevent aggravation of osteoporosis and periodontitis. [ABSTRACT FROM AUTHOR]

It was hypothesized that periodontal diseases could be influenced by nutrition and food types. However, the role of nutritional factors in the risk of periodontal disease has not been clearly elucidated. This study was aimed at investigating the relationship between coffee, green tea, or soft drink intake and periodontitis. This prospective cohort study used epidemiological data from 2004 to 2016 from the Korean Genome and Epidemiology Study. Among 173,209 participants, 9,933 with periodontitis and 124,922 controls were selected. The frequency histories of coffee/green tea/soft drink intake among the participants were analyzed, and intake was categorized as no drink, mild drink (one time a month through six times a week), and heavy drink (one or more times a day). Variable factors were adjusted using logistic regression analysis (adjusted model). The chi-square test and independent t -test were used for statistical analysis. Adjusted odds ratio (aOR) for coffee or green tea intake and periodontitis were not statistically significant. The aOR was 1.16 (95% confidence interval CI = 1.11 –1.21, P < 0.001) for mild soft drink intake and 1.02 (95 % CI = 0.96 –1.09, P = 0.518) for heavy soft drink intake. Subgroup analysis showed that mild soft drink intake was significant across all groups (P < 0.05), whereas coffee and green tea intakes were not significant in any subgroup. Overall, the study elucidated an association between mild soft drink intake and periodontitis. [ABSTRACT FROM AUTHOR]

Objective To investigate the bidirectional relation between RA and depression. Methods Data from the Korean Health Insurance Review and Assessment Service – National Sample Cohort from 2002 to 2013 were analysed. Patients ≥20 years of age were included. Study I was conducted with 38 087 depression patients and 152 348 matched control participants. Study II was conducted with 7385 RA patients and 29 540 matched control participants. Stratified Cox proportional hazards models were used to analyse the hazard ratios (HRs) for depression and RA (study I) and for RA and depression (study II). The data were adjusted by the Charlson comorbidity index; rheumatic disease was excluded. Subgroups were also analysed according to age and sex. Results A total of 0.7% (1260/38 087) of the depression group and 0.6% (883/152 348) of the control I group had RA (P  = 0.02). The HR for RA in the depression group was not significantly higher than that in control I group. In study II, 5.5% (408/7385) of the RA group and 4.3% (1246/29 540) of the control II group presented with depression (P  < 0.001). The RA patients showed an adjusted depression HR that was 1.20 times higher (95% CI 1.07, 1.34; P  = 0.002) than that of the control group. The >30-years-old and women subgroups of RA patients showed higher depression HRs than the control subgroups. Conclusion RA increased the risk of depression; however, depression did not increase the risk of RA in the Korean adult population. [ABSTRACT FROM AUTHOR]

This study aimed to compare the risk of chronic periodontitis (CP) between participants who underwent tonsillectomy and those who did not (control participants) using a national cohort dataset. Patients who underwent tonsillectomy were selected from a total of 514,866 participants. A control group was included if participants had not undergone tonsillectomy from 2002 to 2015. The number of CP treatments was counted from the date of the tonsillectomy treatment. Patients who underwent tonsillectomy were matched 1:4 with control participants who were categorized based on age, sex, income, and region of residence. Finally, 1044 patients who underwent tonsillectomy were matched 1:4 with 4176 control participants. The adjusted estimated value of the number of post-index date (ID) CP did not reach statistical significance in any post-ID year (each of p > 0.05). In another subgroup analysis according to the number of pre- ID CP, it did not show statistical significance. This study revealed that tonsillectomy was not strongly associated with reducing the risk of CP. Even though the tonsils and periodontium are located adjacently, and tonsillectomy and CP may be related to bacterial inflammation, there was no significant risk of CP in patients undergoing tonsillectomy. [ABSTRACT FROM AUTHOR]

Objectives. Chronic inflammatory disease might affect osteoporosis; however, few studies have reported the association between herpes zoster and osteoporosis. The goal of this study was to estimate the association between herpes zoster and osteoporosis in Korean residents. Methods. The Korean National Health Insurance Service-National Sample Cohort, which includes individuals aged ≥ 50 years, was assessed from 2002 to 2013. In total, 68,492 osteoporosis participants were matched with 68,492 control participants at a ratio of 1:1 by age, sex, income, and region of residence. We assayed the prior histories of herpes zoster in the osteoporosis and control groups. The diagnoses of herpes zoster and osteoporosis were based on ICD-10 codes and claim codes. Crude and adjusted models of odds ratios (ORs) were explored using conditional logistic regression analyses, and the 95% confidence intervals (CIs) were computed. The participants were stratified according to age, sex, income, and region of residence. Subgroup analyses were performed to investigate the role of age and sex. Results. The rate of herpes zoster in the osteoporosis group (5.1% [3,487/68,492]) was higher than that in the control group (4.0% [2,738/68,492]). The adjusted OR of herpes zoster in the osteoporosis group was 1.17 (95% CI = 1.11-1.24). In the subgroup analyses, the adjusted OR was 1.34 (95% CI = 1.01-1.78) among males aged < 65 years, 1.20 (95% CI = 1.12-1.29) among females aged < 65 years, and 1.19 (95% CI = 1.04-1.36) among males aged ≥ 65 years. Conclusion. The ORs of herpes zoster were increased among the osteoporosis patients. This correlation was reliable in all subgroups by age and sex except group of women ≥ 65 years old. [ABSTRACT FROM AUTHOR]

Objectives: The present study evaluated the associations between gastroesophageal reflux disease (GERD) and head and neck cancer using a national sample cohort of the Korean population. Design: We designed two studies using data collected from patients aged ≥40 years in the Korean National Health Insurance Service‐National Sample Cohort from 2002 to 2013. Main outcome Measures: Study I included participants with GERD matched 1:2 with controls and analysed the incidences of lip and oral cavity, oropharynx, hypopharynx and larynx cancers. Study II included participants with larynx cancer matched 1:4 with controls and analysed the previous histories of GERD. Head and neck cancer was identified using medical claim codes for surgical, radiation and chemotherapeutic treatments and death records from the National Statistical Office. Crude and adjusted hazard ratios (HRs) were analysed using the Cox proportional hazard model. Crude and adjusted odds ratios (ORs) were analysed using unconditional logistic regression analyses. Subgroup analyses were performed on groups stratified by age and sex. Results: The adjusted HR for larynx cancer was 2.32 (95% confidence interval (CI) = 1.53‐3.52, P < 0.001) in the GERD group. However, the HRs for lip and oral cavity cancer, oropharynx cancer and hypopharynx cancer were not statistically significant (study I). The adjusted OR for GERD was 2.03 (95% CI = 1.40‐2.96, P < 0.001) in the larynx cancer group; consistent results were obtained in subgroup analyses. Conclusion: Gastroesophageal reflux disease increases the risk of larynx cancer. [ABSTRACT FROM AUTHOR]

Several previous studies demonstrated the risk of stroke in asthma patients. The aim of this study was to evaluate the risk of hemorrhagic and ischemic stroke in asthma patients, independent of age, sex, income, region of residence, and past medical histories. The Korean Health Insurance Review and Assessment Service-National Sample Cohort from 2002 through 2013 was used. Overall, 111,364 asthma patients ≥ 20 years old were matched to 111,364 control participants for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia. Asthma was classified using ICD-10 codes (J45 and J46) and medication history. The admission histories were investigated for hemorrhagic stroke (I60-I62) and ischemic stroke (I63) using ICD-10 codes. The crude and adjusted (age, sex, income, region of residence, hypertension, diabetes, dyslipidemia, ischemic heart disease, and depression) hazard ratios (HRs) for hemorrhagic and ischemic stroke in asthma patients were analyzed using a Cox proportional hazards model. Subgroup analyses were conducted according to age and sex. Hemorrhagic and ischemic stroke were found in 0.7% (795/117,364) and 2.4% (922/117,364) of the asthma group and in 0.8% (922/117,364) and 2.6% (93,079/117,364) of the control group, respectively. The asthma group demonstrated adjusted HRs of 0.86 (95% confidence interval [CI] = 0.78-0.94, p = 0.002) for hemorrhagic stroke and 0.91 (95% CI = 0.86-0.95, p = 0.002) for ischemic stroke. None of the subgroups of asthma patients showed higher HRs for stroke. Asthma did not elevate the risk of either hemorrhagic or ischemic stroke. [ABSTRACT FROM AUTHOR]

To evaluate the association between sudden sensorineural hearing loss (SSNHL) and rheumatoid arthritis (RA) among a national sample cohort from Korea. Data were collected from 2002 through 2013 for individuals aged ≥ 20 years in the Korean National Health Insurance Service (NHIS)-National Sample Cohort. We extracted the data from RA patients (n = 7619) and 1:4-matched controls (n = 30,476) and analyzed the occurrence of SSNHL. Matching was performed based on age, sex, income, region of residence, and medical history. RA was diagnosed based on International Classification of Disease-10 (ICD-10) codes (M05 or M06) and prescriptions for the antirheumatic drugs. SSNHL was diagnosed based on the relevant ICD-10 code (H912). Among the SSNHL participants, we included only those who had undergone an audiometry exam (claim codes: E6931-E6937, F6341-F6348) and received treatment with steroids. The crude and adjusted hazard ratios (HRs) were calculated using Cox-proportional hazard models, and the 95% confidence intervals (CIs) were determined. Subgroup analyses based on age and sex were also performed. The rate of SSNHL in the RA group (0.8% [62/7619]) was higher than that in the control group (0.6% [177/30,476], P = 0.021). The crude and adjusted HRs for SSNHL were 1.40 (95% CI = 1.05-1.87) and 1.39 (95% CI = 1.04-1.86), respectively, in the RA group (each P < 0.05). The relationship between RA and SSNHL was observed primarily in patients aged ≥ 50 years and men. The risk of SSNHL is higher in patients with RA. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to evaluate the association between hysterectomy and the occurrence of stroke in a Korean national cohort.Study Design: Data from 2002 to 2013 were collected for individuals in the Korean National Health Insurance Service-National Cohort. We extracted data for patients who had undergone a hysterectomy (N = 11,280) and a 1:4 matched control group (N = 45,120) and then analyzed the occurrence of stroke. The patients were matched according to age, sex, income, region of residence, and medical history.Main Outcome Measures: Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using a Cox proportional hazards model. Subgroup analyses were based on age (those under and those over 45 years of age) and type of hysterectomy (with or without bilateral oophorectomy).Results: No significant difference in risk of hemorrhagic stroke (adjusted HR = 0.91, p = 0.592) or ischemic stroke (adjusted HR = 0.85, p = 0.188) was found between women with and without hysterectomy. No significant differences were found in the subgroup analyses according to age or type of hysterectomy for hemorrhagic and ischemic stroke.Conclusion: Over a mean follow-up of 6 years, hysterectomy is not associated with an increased risk of either ischemic or hemorrhagic stroke at any age after adjusting for CVD risk factors including, hypertension, diabetes mellitus, and dyslipidemia, regardless of bilateral oophorectomy. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study is to evaluate the risk of stroke (hemorrhagic or ischemic) after neck dissection in thyroid cancer patients in Korea using national cohort data. Methods: Using the national cohort study from the Korean Health Insurance Review and Assessment Service, patients with neck dissection for thyroid cancer (1,041) and control participants (4,164) were selected and matched 1:4 (age, gender, income, and region of residence). The Chi-square test, Fischer’s exact test, and the Cox-proportional hazard model were used. The Cox-proportional analysis used a crude model and an adjusted model for age, gender, income, region of residence, hypertension, diabetes, dyslipidemia. Results: None of the participants had suffered hemorrhagic stroke in the neck dissection group, while 0.3% (13/4,164) of participants had suffered hemorrhagic stroke in the control group (P = 0.085). In total, 0.8% (8/1,041) of participants had suffered an ischemic stroke in the neck dissection group, and 0.7% (31/4,133) of participants had suffered an ischemic stroke in the control group (P = 0.936). The adjusted hazard ratio for ischemic stroke after neck dissection was 1.06 (95% confidence interval [CI] = 0.49–2.31, P = 0.884). Conclusion: The risk of hemorrhagic or ischemic stroke was not higher in thyroid cancer patients who underwent neck dissection than that in the matched control group. [ABSTRACT FROM AUTHOR]

Conclusion:The elevated neutrophil-to-lymphocyte ratio (NLR) value in children with sudden sensorineural hearing loss (SSNHL) would suggest the inflammatory etiology of pediatric SSNHL. The results of this study may suggest NLR value can be used as a useful indicator, which is associated with the disease severity in pediatric SSNHL. Objectives:This study aimed to elucidate any clues of inflammatory etiology, which might be related with the development of pediatric SSNHL, using calculated NLR. Methods:Forty-six patients aged younger than 19 years, who were admitted to the hospital with the diagnosis of SSNHL, were included in the study. Forty-six healthy children were matched as control group according to their propensity score. The complete blood cell count, calculated NLR, platelet-to-lymphocyte ratio (PLR), and mean platelet volume (MPV) were compared. The relationship between NLR and the initial hearing level was also investigated. Results:The mean NLR value was 2.86 ± 2.58 in the SSNHL group, whereas the mean NLR value was 1.63 ± 0.87 in the control group. The mean NLR value of the SSNHL children was significantly higher than that of the control group (p = .023). There was a positive correlation between the NLR value and initial hearing level (r = .312,p = .037). [ABSTRACT FROM PUBLISHER]

Research on the effect of low-fat intake on hearing is limited. This study aimed to elucidate the relationship between fat, carbohydrate and protein intake and the presence of hearing discomfort among the elderly. The Korean National Health and Nutrition Examination Survey was conducted from 2009 through to 2012. A total of 4615 participants ranging in age from 60 to 80 years underwent a pure-tone audiometric evaluation, a physical examination and a nutritional survey. The associations between the participants’ hearing thresholds and their protein/fat/carbohydrate intake/total energy intake were analysed using simple and multiple regression models with complex sampling adjusted for confounding factors, such as BMI, income level, smoking status and a history of hypertension, hyperlipidaemia and diabetes. Low fat and protein intakes were associated with hearing discomfort (OR 0·82, 95 % CI 0·71, 0·96, P=0·011; OR 0·81, 95 % CI 0·67, 0·96, P=0·017, respectively). This study revealed that low fat and protein intakes are associated with hearing discomfort in the elderly Korean population. [ABSTRACT FROM PUBLISHER]

Concerns about the hazards of statins on the development and mortality of stomach cancers remain controversial. Here, we investigated the likelihood of incident gastric cancers and related mortality depending on statin exposure, statin type, and the duration of use. This nested case–control-designed study was composed of 8798 patients who were diagnosed with gastric cancer and matched with 35,192 controls at a 1:4 ratio based on propensity scores of age, sex, residential area, and income from the Korean National Health Insurance Service—Health Screening Cohort database (2002–2015). Propensity score overlap weighting was adjusted to balance the baseline covariates. Overlap propensity score-weighted logistic regression analyses were assessed to determine associations of the prior use of statins (any statin, hydrophilic statins vs. lipophilic statins) with incident gastric cancer and its mortality depending on the medication duration (<180 days, 180–545 days, and >545 days) after adjusting for multiple covariates. After adjustment, the use of any statin, hydrophilic statins, or lipophilic statins showed significant associations with lower odds for incident stomach cancer when used for a short-term period (180–545 days) (OR = 0.88, 95% CI = 0.81–0.86, p = 0.002; OR = 0.78, 95% CI = 0.66–0.92, p = 0.004; and OR = 0.91, 95% CI = 0.84–0.99, p = 0.039, respectively) compared to the control group. Hydrophilic statin use for 180–545 days was associated with 53% lower overall mortality (OR = 0.47; 95% CI = 0.29–0.77). In subgroup analyses, beneficial effects on both cancer development and mortality persisted in patients ≥65 years old, patients with normal blood pressure, and patients with high fasting glucose levels. There were no such associations with long-term statin use (>545 days). Thus, the current nationwide cohort study suggests that prior short-term statin use may have anti-gastric cancer benefits in elderly patients with hyperglycemia. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the association of income level with susceptibility to coronavirus disease 2019 (COVID-19) and COVID-19 morbidity and mortality. Using the Korean National Health Insurance COVID-19 Database cohort, medical claim data from 2015 through 2020 were collected. A total of 7943 patients who were diagnosed with COVID-19 from 1 January 2020 to 4 June 2020 were included. A total of 118,914 participants had negative COVID-19 PCR tests. Income levels were classified by 20th percentiles based on 2019 Korean National Health Insurance premiums. The 20th percentile income levels were categorized into three groups (low, middle, and high). The relationship of income level with susceptibility to COVID-19 and COVID-19 morbidity and mortality was analyzed using logistic regression analysis. A high income level was related to lower odds of COVID-19 infection (adjusted odds ratio (aOR) = 0.79, 95% confidence interval (CI) = 0.75–0.83, p < 0.001). The negative association between income level and COVID-19 infection was maintained in all subgroups. Patients with low income levels were susceptible to COVID-19 infection; however, there was no relation of COVID-19 morbidity and mortality with income level in the Korean population. [ABSTRACT FROM AUTHOR]

Background: There is controversial evidence of the associations of asthma and chronic obstructive pulmonary disease (COPD) with the risk and outcomes of Coronavirus Disease 2019 (COVID-19). We aimed to evaluate the effects of asthma and COPD on the susceptibility to and severity of COVID-19. Methods: Data from a nationwide COVID-19 cohort database by the Korea National Health Insurance Corporation were utilized. A total of 4066 COVID-19 patients (1 January 2020 through 4 June 2020) were 1:4 matched with 16,264 controls with regard to age, sex, and income. Asthma and COPD were defined as diagnostic codes (ICD-10) and medication claim codes. Conditional and unconditional multivariate logistic regression were applied to analyze the susceptibility to and severity of COVID-19 associated with asthma and COPD. Results: The prevalence of mild and severe asthma/COPD did not differ between the COVID-19 and control patients in the multivariate analyses. Among the total 4066 COVID-19 patients, 343 (8.4%) had severe COVID-19, of whom 132 (3.2% of the total COVID-19 patients) died. Regarding the outcomes of COVID-19, neither mild nor severe asthma were associated with the severity or mortality of COVID-19 after adjusting for other variables. However, severe COPD was a significant risk factor for severe COVID-19 (odds ratio (OR) = 2.23, 95% confidence intervals (CI): 1.08–4.60, p = 0.030) and the mortality of COVID-19 in the multivariate analyses (OR = 3.06, 95% CI: 1.14–8.2, p = 0.026). Conclusions: In a Korean nationwide cohort, neither asthma nor COPD were associated with COVID-19, but severe COPD was associated with the severity and mortality of COVID-19. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the associations of the susceptibility to, morbidity of, and mortality due to coronavirus disease 2019 (COVID-19) with thyroid diseases. Korea National Health Insurance Database Coronavirus disease 2019 (NHID-COVID-19) medical claim code data from 2015 to 2020 were analyzed. A total of 8070 COVID-19 patients and 32,280 matched control participants were evaluated for histories of hypothyroidism, hyperthyroidism, Graves' disease, thyroiditis, and autoimmune thyroiditis. The relationships of susceptibility to, morbidity of, and mortality due to COVID-19 with hypothyroidism, hyperthyroidism, Graves' disease, thyroiditis, and autoimmune thyroiditis were analyzed using a conditional logistic regression. Hypothyroidism, hyperthyroidism, Graves' disease, thyroiditis, and autoimmune thyroiditis were not associated with susceptibility to, morbidity of, or mortality due to COVID-19. Graves' disease was related to higher odds of mortality due to COVID-19 in the adjusted model but the confidence interval (CI) was wide, probably due to the small number of deaths among patients with Graves' disease (aOR = 11.43, 95% CI = 1.29–101.22, p = 0.029). Previous histories of hypothyroidism, hyperthyroidism, Graves' disease, thyroiditis, and autoimmune thyroiditis were not related to susceptibility to COVID-19. In addition, prior histories of thyroid diseases were not related to increased risks of COVID-19-related morbidity and mortality. [ABSTRACT FROM AUTHOR]

Background: Premenopausal hysterectomy is associated with a decreased ovarian reserve, follicular atresia, and subsequently reduced long-term estrogen secretion. Therefore, women who undergo hysterectomy will experience greater gradual bone mineral loss than women with an intact uterus and have an increased risk of osteoporosis.Objective: This study aimed to evaluate the association between hysterectomy without/with bilateral oophorectomy and the occurrence of osteoporosis using a national sample cohort from South Korea.Study Design: Using the national cohort study from the Korean National Health Insurance Service, we extracted data for patients who had undergone hysterectomy (n=9082) and for a 1:4 matched control group (n=36,328) and then analyzed the occurrence of osteoporosis. The patients were matched according to age, sex, income, region of residence, and medical history. A Cox proportional hazards model was used to analyze the hazard ratios and 95% confidence intervals. Subgroup analyses were performed based on age and bilateral oophorectomy status. The age of the participants was defined as the age at the time of hysterectomy.Results: The adjusted hazard ratio for osteoporosis was 1.45 (95% confidence interval, 1.37-1.53, P<.001) in the hysterectomy group. The adjusted hazard ratios for osteoporosis in the different age subgroups of this group were 1.84 (95% confidence interval, 1.61-2.10) for ages 40-44 years, 1.52 (95% confidence interval, 1.39-1.66) for ages 45-49 years, 1.44 (95% confidence interval, 1.28-1.62) for ages 50-54 years, 1.61 (95% confidence interval, 1.33-1.96, all P<.001) for ages 55-59 years, and 1.08 (95% confidence interval, 0.95-1.23, P=.223) for ages ≥60 years. The adjusted hazard ratios for osteoporosis according to hysterectomy/oophorectomy status were 1.43 (95% confidence interval, 1.34-1.51) in the hysterectomy without bilateral oophorectomy group and 1.57 (95% confidence interval, 1.37-1.79) in the hysterectomy with bilateral oophorectomy group.Conclusion: The occurrence of osteoporosis was increased in patients who had undergone hysterectomy compared with that in matched control subjects regardless of bilateral oophorectomy status. [ABSTRACT FROM AUTHOR]

Introduction: Findings on the association between statin therapy and Parkinson's disease (PD) occurrence have been inconsistent. This study aimed to identify the association between statin use and PD in participants with a history of hyperlipidemia or blood cholesterol >200 in a Korean population to exclude nonstatin users owing to normal lipid values.Methods: We conducted a nested case-control analysis using the Korean National Health Insurance Service-National Sample Cohort assessed between 2002 and 2015. We identified 3026 PD cases. A total of 12,104 controls were then individually matched by age, sex, income, and region of residence at a ratio of 1:4. Potential confounders comprised basic demographic factors, lifestyle factors, various medical conditions and comorbidities. A conditional/unconditional logistic regression method was applied.Results: Compared with statin use for <6 months, adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for 6-12 months of statin use and ≥12 months of statin use were 1.03 (0.92-1.15) and 1.61 (1.35-1.93) after adjustment for confounders, respectively (P = 0.664 and P < 0.001). In analyses according to statin solubility, only the association between lipophilic statin use for ≥12 months and PD maintained statistical significance, with an aOR of 1.64 (95% CI = 1.34-2.01, P < 0.001). These relations were consistent in subgroup analyses by covariates.Conclusions: Statin use for more than 12 months was associated with a higher probability of PD in the Korean population with hyperlipidemia. This probability was significant for lipophilic statins but not hydrophilic statins. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to evaluate the rate of depression during the COVID-19 pandemic compared to that during the prepandemic period.Methods: Data from participants in the Korean Community Health Survey in 2019 and 2020 aged ≥ 19 years old were analyzed. In total, the data of 223,306 participants from the 2020 group were compared with the data of 217,133 participants from the 2019 group regarding the experience and severity of depression. The experience of depression was surveyed in terms of a history of sadness or despair for ≥2 weeks in the last year. In addition, the PHQ-9 scores were used, and participants with PHQ-9 scores ≥10 were recategorized as having moderate to severe depression. The odds for depression of the 2020 group compared to the 2019 group based on the survey and PHQ-9 scores were calculated using simple or multiple logistic regression with complex sampling with weighted values.Results: The rate of depression experience was lower in the 2020 group than in the 2019 group. The odds of experiencing depression were lower in the 2020 group than in the 2019 group (adjusted odds ratio [aOR] = 0.95, 95% confidence intervals [95% CI] = 0.91-0.98, P = 0.004). The odds of moderate to severe depression were also lower in the 2020 group than in the 2019 group (aOR=0.92, 95% CI=0.88-0.97, P = 0.001).Conclusion: The rate of depression experience was not higher during the COVID-19 pandemic than during the prepandemic period in Korea. [ABSTRACT FROM AUTHOR]