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

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

Investigating the Connection between Chronic Periodontitis and Parkinson's Disease: Findings from a Korean National Cohort Study

Recent research suggests a potential relevance between chronic periodontitis (CP) and Parkinson's disease (PD), raising concerns about comorbid PD among elderly CP patients. However, the epidemiologic basis for this association remains unclear. Employing a nested case-control design, this study explored the association between CP and subsequent PD occurrences in Korean adults, leveraging a validated national population-based dataset covering the period from 2002 to 2019. It included 8794 PD patients and 35,176 matched control individuals, established through propensity score matching for age, sex, residential area, and income. Baseline characteristics were compared using standardized differences, and logistic regression was employed to assess the impact of CP histories on PD likelihood while controlling for covariates. We performed a thorough examination of CP events within both 1-year and 2-year intervals preceding the index date, incorporating subgroup analyses. Our analysis revealed no statistically significant association between CP history and PD development overall. However, subgroup analysis revealed a slightly increased likelihood of PD development among CP individuals with a high disease burden (Charlson Comorbidity Index score ≥ 2). In conclusion, although our study did not find a significant overall association between CP history and PD development, the elevated likelihood of PD in subgroups with high disease burden may suggest that comorbidities influence PD probability among certain CP patients. Considering comorbid conditions in PD screening for some individuals with CP may be also important.

Associations between Chronic Kidney Disease and Migraine Incidence: Findings from a Korean Longitudinal Big Data Study

While headaches frequently occur in individuals with chronic kidney disease (CKD), there are few statistical evaluations of their connection to migraines in population-based studies. In this nationwide longitudinal follow-up study of Korean health examination data (2002-2019), a total of 15,443 participants with CKD and 61,772 matched controls were enrolled. We applied overlap-weighted Cox proportional hazard regression models to assess hazard ratios, examining the correlation between CKD and the development of migraines. After accounting for various factors, we observed a modest reduction of approximately 11% in the likelihood of migraine occurrence among CKD patients (95% confidence intervals = 0.81-0.97) during the 16-year monitoring period. Subgroup analysis revealed a significant association among specific demographic and health conditions, including individuals aged 70 or older, females, overweight individuals, nonsmokers, and those without hypertension or diabetes. Our research may indicate a potential relationship between CKD and the onset of migraines in Korean adults, suggesting a slight reduction in the probability of the occurrence of migraines among those with CKD. These findings emphasize the need for attentive follow-up and preventive management in individuals without the identified protective factors, particularly in male CKD patients under the age of 70 with hypertension.

Association between the Use of Proton Pump Inhibitors and Cardiovascular Diseases: A Nested Case-Control Study Using a National Health Screening Cohort

We investigated the association of proton pump inhibitor (PPI) use with the risk of stroke and ischemic heart disease (IHD). The Korean National Health Insurance Service-Health Screening cohort from 2002 to 2003, the participants of which were followed up until 2019, was used. In study I, 45,905 participants who were diagnosed with stroke were matched with 91,810 control I participants. The history of PPI medication was examined. In study II, 40,928 participants who were diagnosed with IHD were matched with 81,856 control II participants. In both study I and study II, the previous history of PPI medication was examined. A propensity score overlap-weighted multivariable logistic regression analysis was conducted to estimate the overlap-weighted odds ratios (ORs) of PPI use for stroke (study I) and IHD (study II). Current PPI use was linked with higher odds for stroke in study I. The odds for stroke were higher in groups with a longer duration of PPI use (OR = 0.96 [95% CI = 0.92-1.00] < 1.55 [1.50-1.61] < 1.62 [1.57-1.68] for < 30 days, 30 to 180 days, and ≥180 days of PPI use). Previous PPI use was linked with higher odds for IHD in study II. The odds for stroke were higher in groups with a longer duration of PPI use (OR = 1.13 [95% CI = 1.08-1.18] < 2.12 [2.04-2.21] < 2.60 [2.51-2.69] for <30 days, 30 to 180 days, and ≥180 days of PPI use). Current PPI medication is associated with a high risk of stroke and IHD. A longer duration of PPI medication was related to a higher risk of stroke and IHD. However, a prior history of PPI medication was not linked with a high risk of stroke or IHD.

Unlocking the Protective Potential of Upper Respiratory Infection Treatment Histories against Alzheimer's Disease: A Korean Adult Population Study

With increasing interest in the inflammation-pathogen infection hypothesis and its potential links to Alzheimer's disease (AD) development, there is growing consideration of using upper respiratory infection (URI) treatments as interventions for AD. This nested case-control study explored the potential association between prior URI histories and AD development in a Korean adult population using the national health screening cohort data (2002-2019). The study included 26,920 AD patients and 107,680 matched control individuals, focusing on those seeking respiratory treatment. Logistic regression analyses assessed the impact of URI histories and treatment on AD risk while adjusting for covariates. Our results revealed that over a 1-year period, individuals with URI histories (≥1, ≥2, or ≥3 instances) exhibited decreasing probabilities of developing AD, with risk reductions of 19%, 15%, and 12%, respectively. Expanding our investigation to a 2-year period consistently showed a 17% reduction in AD risk. This effect remained robust across diverse demographic groups and after adjusting for covariates, encompassing comorbidities, hypertension, hyperlipidemia, blood glucose levels, and lifestyle factors. Subgroup analyses further substantiated this association. In conclusion, our findings cautiously suggest a potential protective role of prior URI treatment histories in mitigating the risk of AD development.

Investigation of changes in the physical activity and fall experience before and after the COVID-19 pandemic

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.

Increased Risk of Benign Prostate Hyperplasia (BPH) in Patients with Gout: A Longitudinal Follow-Up Study Using a National Health Screening Cohort

A previous study reported a high risk of benign prostatic hyperplasia (BPH) in patients with gout. This study intended to evaluate the risk of BPH in gout patients. A total of 514,866 Korean National Health Insurance Service-Health Screening Cohorts were retrieved from 2002 to 2019. Among these individuals, 14,961 gout patients and 58,764 control participants were matched based on demographic factors. The incidence of BPH during the follow-up periods was collected for both the gout and control groups. The risk of BPH was analyzed using stratified Cox proportional hazard models, and hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. Secondary analyses were conducted based on demographic factors and comorbidities. The incidence of BPH was 23.40% in gout patients and 20.70% in control participants. In the adjusted model, the HR of BPH was 1.13-fold higher in gout patients than in the control group (95% CI = 1.09-1.18). Compared with the ≥60-year-old group, the <60-year-old group demonstrated a higher HR for BPH in gout patients (1.19 [1.13-1.24] vs. 1.07 [1.01-1.13]). The risk of BPH in gout patients was consistent according to various comorbidities. Patients with gout demonstrated a greater risk of BPH than participants without gout. The young adult population had a higher risk of BPH related to gout.

Gout and Migraines: Exploring the Complex Link in a 16-Year Longitudinal Study of the Korean Population

Despite the growing prevalence of gout and its associated health concerns as a chronic disorder, population-based studies on its link to migraines are scarce. We conducted a 16-year longitudinal study in a Korean population to investigate the relationship between gout and migraines, including different subtypes. We enrolled 23,137 patients with gout and matched them with 92,548 controls based on age, sex, income, and residence. Using Cox proportional hazards models, we calculated hazard ratios to assess the likelihood of migraines while considering relevant factors. During the follow-up, 1000 gout patients and 3214 controls experienced migraines. After adjusting for various factors, including demographics, health-related variables, and weight categories, the gout group had a 1.26-fold higher likelihood of developing migraines compared to the group without gout. This association was particularly strong for migraines without aura, while it was not significant for migraines with aura. In summary, our study reveals a significant link between gout and migraines in the Korean population, emphasizing the complex relationship among chronic disorders, with a specific focus on migraine subtypes.

Association between Tonsillectomy and Cardiovascular Diseases in Adults

This study aimed to evaluate the association between tonsillectomy and cardiovascular diseases (CVDs) in the Korean adult population. Using data from the 2002-2015 Korean National Health Insurance Service-Health Screening Cohort, a total of 1082 participants aged 40 years or older who had undergone tonsillectomy were matched with 4328 control individuals for age, sex, income, and region of residence. We evaluated the incidence of CVDs in both the tonsillectomy and control groups and calculated the hazard ratios (HRs) of stroke, ischemic heart disease (IHD), and heart failure (HF) for participants who underwent tonsillectomy using a stratified Cox proportional hazard model. The incidence rates of stroke (81.3 vs. 46.6 per 10,000 person-years) and IHD (112.3 vs. 64.9 per 10,000 person-years) were significantly higher in patients who had undergone tonsillectomy than in the control group. After adjustment, the tonsillectomy group exhibited a 1.78-fold and 1.60-fold higher occurrence of stroke (CI = 1.32-2.42, p < 0.001) and IHD (CI = 1.24-2.08, p < 0.001), respectively, compared to the control group. However, there was no significant difference in the incidence rate of tonsillectomy and control groups (11.1 vs. 6.1 per 10,000 person-years). The HR of HF did not differ significantly between the tonsillectomy and control groups in the adjusted model (p = 0.513). We identified a significant relationship between a history of tonsillectomy and occurrence of stroke/IHD in the Korean adult population.

Association between Asthma and Periodontitis

The current study aimed to investigate the association between asthma and periodontitis in the Korean adult population. Data from the Korean Genome and Epidemiology Study Health Examinees between 2004 and 2016 were considered. Of the 173,209 participants, 2521 asthmatic and 132,806 control participants were selected. The participants were categorized according to their current status of asthma, as 'well-controlled', 'being treated', and 'not being treated'. The prevalence of periodontitis was found to be significantly higher in the participants with asthma (13.1%) than in the controls (7.3%). In the fully adjusted model, the patients with asthma had a higher odds ratio (OR = 1.79, 95% confidence interval [CI] = 1.59-2.02, p < 0.001) for periodontitis than those without asthma. The results were consistent across all the age and sex subgroups. The adjusted ORs for periodontitis were 2.15 (95% CI = 1.68-2.76, p < 0.001) in the 'well-controlled' asthma group, 1.44 (95% CI = 1.16-1.78, p < 0.001) in the 'being treated' asthma group, and 1.86 (95% CI = 1.55-2.22, p < 0.001) in the 'not being treated' asthma group compared to the control group. Overall, we found asthma to be associated with periodontitis in Korean adults, and the participants with well-controlled asthma had the highest ORs for periodontitis.

Is the 'safe zone' identified in preoperative computed tomography helpful for choosing optimal implant for fixation of radial head fracture?

The purpose of this study is to assess the clinical significance of the radiologic safe zone based on computed tomography and to compare the outcomes of three different implants for fixation of isolated radial head fractures. We retrospectively reviewed 367 patients who underwent internal fixation for isolated radial head fractures. We newly defined two subtypes of Mason type II fractures associated with the radiographic safe zone (IIA, two-part fracture allowing for safe fixation of plate; IIB, two-part fracture not allowing for safe fixation). 170 patients (CCS group, n = 82; HCS group, n = 31; plate group, n = 57) were investigated with no significant differences in demographics. The range of pronation and supination at 1 month postoperatively (P = 0.04 and P = 0.04) and the range of supination at 6 and 12 months postoperatively (P = 0.03 and P = 0.03) were significantly smaller in the plate group. In Mason type IIB fractures, the average MEPS was higher in the CCS and HSC groups than in the plate group (P = 0.01 and P = 0.02). And the average DASH score was lower in the CCS and HCS groups (P < 0.01 and P < 0.01). Evaluation of the radiologic safe zone is potentially helpful in selecting better surgical fixation option. For type III fractures, 2.3-mm cortical screws would be a better option than Acutrak screws. Plates would not be suitable for type IIB radial head fractures.

Risk for Esophageal Cancer Based on Lifestyle Factors-Smoking, Alcohol Consumption, and Body Mass Index: Insight from a South Korean Population Study in a Low-Incidence Area

Esophageal cancer constitutes a global public health challenge. However, South Korean population-specific information on the association of lifestyle (smoking, alcohol consumption, and obesity status) with esophageal cancer risk is sparse. This nested case-control study analyzed the Korean national health screening cohort data (2002-2019) of 1114 patients with esophageal cancer and 4456 controls (1:4 propensity-score matched for sex, age, income, and residential region). Conditional and unconditional logistic regression analyses, after adjustment for multiple covariates, determined the effects of lifestyle factors on esophageal cancer risk. Smoking and alcohol consumption increased the esophageal cancer risk (adjusted odds ratio [95% confidence interval]: 1.37 [1.15-1.63] and 1.89 [1.60-2.23], respectively). Overweight (body mass index [BMI] ≥ 23 to <25 kg/m2), obese I (BMI ≥ 25 to <30 kg/m2), or obese II (BMI ≥ 30 kg/m2) categories had reduced odds of esophageal cancer (0.76 [0.62-0.92], 0.59 [0.48-0.72], and 0.47 [0.26-0.85], respectively). In the subgroup analyses, the association of incident esophageal cancer with smoking and alcohol consumption persisted, particularly in men or those aged ≥55 years, whereas higher BMI scores remained consistently associated with a reduced esophageal cancer likelihood across all age groups, in both sexes, and alcohol users or current smokers. Underweight current smokers exhibited a higher propensity for esophageal cancer. In conclusion, smoking and alcohol drinking may potentially increase the risk, whereas weight maintenance, with BMI ≥ 23 kg/m2, may potentially decrease the risk, for esophageal cancer in the South Korean population. Lifestyle modification in the specific subgroups may be a potential strategy for preventing esophageal cancer.

Alzheimer's Disease and Different Types of Cancer Likelihood: Unveiling Disparities and Potential Protective Effects in a Korean Cohort Study

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.

An elevated likelihood of stroke, ischemic heart disease, or heart failure in individuals with gout: a longitudinal follow-up study utilizing the National Health Information database in Korea

Objective

Accumulating evidence from other countries indicates potential associations between gout and cardiovascular diseases; however, the associations of gout with cardiovascular diseases, particularly stroke, ischemic heart disease, and heart failure, remain ambiguous in the Korean population. We hypothesized that individuals with gout are at a higher likelihood of stroke, ischemic heart disease, or heart failure. This study expands upon previous research by ensuring a comparable baseline between patient and control groups and analyzing 16 years of data derived from an extensive healthcare database.

Methods

We selected 22,480 patients with gout and 22,480 control individuals from the Korean National Health Insurance Service-Health Screening Cohort database (2002-2019), and matched them at a 1:1 ratio according to sex, age, income, and residence. A Cox proportional hazard model with weighted overlap was employed to examine the relationship between gout and the risk of stroke, ischemic heart disease, or heart failure after adjustment for several covariates.

Results

The incidences of stroke, ischemic heart disease, or heart failure in participants with gout were slightly higher than those in controls (stroke: 9.84 vs. 8.41 per 1000 person-years; ischemic heart disease: 9.77 vs. 7.15 per 1000 person-years; heart failure: 2.47 vs. 1.46 per 1000 person-years). After adjustment, the gout group had an 11% (95% confidence interval [CI] = 1.04-1.19), 28% (95% CI = 1.19-1.37), or 64% (95% CI = 1.41-1.91) higher likelihood of experiencing stroke, ischemic heart disease, or heart failure, respectively, than the control group.

Conclusion

The present findings suggest that individuals with gout in the Korean population, particularly those aged ≥ 60 years, were more likely to have stroke, ischemic heart disease, or heart failure.

Chronic Periodontitis and the Potential Likelihood of Gastric Cancer: A Nested Case-Control Study in the Korean Population Utilizing a National Health Sample Cohort

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.

A higher probability of subsequent stroke and ischemic heart disease in migraine patients: a longitudinal follow-up study in Korea

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.

Longitudinal study of the inverse relationship between Parkinson's disease and cancer in Korea

Despite growing epidemiological evidence, the relationship between Parkinson's disease (PD) and cancer has not been conclusively demonstrated, and related studies are scarce in the Asian population. We aimed to determine the association between PD and subsequent development of various cancers from longitudinal data of a representative sample of Korean adults aged ≥40 years. We retrospectively identified 8381 patients diagnosed with PD from 2002 to 2019 using claims data among 514,866 people of random samples from the Korean National Health Insurance database. We sampled 33,524 age-, sex-, income-, and residential area-matched participants without PD from the same database. The longitudinal associations between PD and overall cancer, as well as 10 common types of cancer, were estimated using multivariable Cox proportional-hazards regression analysis. The adjusted hazard ratio (aHR) of all cancer types was 0.63 (95% confidence interval = 0.57-0.69) in patients with PD compared with matched controls. The aHRs of gastric, thyroid, colorectal, lung, hepatic, and pancreatic cancer and hematological malignancy were 0.69 (0.56-0.85), 0.60 (0.39-0.93), 0.56 (0.44-0.70), 0.71 (0.58-0.84), 0.64 (0.48-0.86), 0.37 (0.23-0.60), and 0.56 (0.36-0.87), respectively. The associations of bladder, gallbladder and biliary duct, and kidney cancer with PD were not statistically significant. Our findings show inverse associations between overall cancer and most cancer types in patients with PD. These inverse associations and their pathogeneses merit further investigation.

Exploring the Link between Chronic Kidney Disease and Parkinson's Disease: Insights from a Longitudinal Study Using a National Health Screening Cohort

Chronic kidney disease (CKD) and Parkinson's disease (PD) are common illnesses found in the geriatric population. A potential link between CKD and PD emergence has been hypothesized; however, existing conclusions are disputed. In this longitudinal research, we analyzed data acquired from the Korean National Health Insurance Service-Health Screening Cohort. The dataset comprised the health information of 16,559 individuals clinically diagnosed with CKD and 66,236 control subjects of comparable ages, all aged ≥40 years. These subjects participated in health examinations from 2002 to 2019. To assess the correlation between CKD and PD, we employed overlap-weighted Cox proportional hazard regression models. The unadjusted, crude hazard ratio for PD was greater in the CKD group than in the control group (crude hazard ration (HR) 1.20; 95% confidence interval (CI) = 1.04-1.39; p = 0.011). However, the Cox proportional hazard regression analysis, incorporating propensity score overlap weighting, revealed no significant discrepancy after considering confounding variables such as demographic factors, socio-economic status, lifestyle, and concurrent health conditions (adjusted HR (aHR), 1.09; 95% CI = 0.97-1.22; p = 0.147). Subgroup analyses showed a higher probability of PD development among certain CKD individuals, including those who resided in rural areas (aHR, 1.19; 95% CI = 1.03-1.37; p = 0.022), maintained a normal weight (aHR, 1.29; 95% CI = 1.08-1.56; p = 0.006), or had fasting blood glucose levels ≥100 mg/dL (aHR, 1.18; 95% CI = 1.00-1.39; p = 0.046). Therefore, these clinical or environmental factors may influence the incidence of PD in CKD patients. In conclusion, our results suggest that the general CKD population may not exhibit a greater propensity for PD than their non-CKD counterparts. However, this might be contingent upon specific lifestyle and comorbid conditions. Thus, certain lifestyle alterations could be crucial in mitigating the potential manifestation of PD in patients diagnosed with CKD.

Changes in the mean incidence and variance of orthopedic diseases before and during the COVID-19 pandemic in Korea: a retrospective study

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.

Relation of Statin Use with Esophageal Cancer

The present study evaluated the association of long-term statin use with the diagnosis and mortality of esophageal cancer in a Korean population. The Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2019 was enrolled. Esophageal cancer patients were matched with control participants for demographic variables. The statin prescription histories were collected and grouped into <180 days, 180 to 545 days, and >545 days of duration. Propensity score overlap weighting was applied to minimize the bias between the esophageal cancer and control groups. The odds ratios (ORs) of the duration of statin use for esophageal cancer were analyzed using propensity score overlap weighted multivariable logistic regression analysis. The esophageal cancer group was classified as dead and surviving patients, and the ORs of the duration of statin use for the mortality of esophageal cancer were analyzed in an identical manner. Secondary analyses were conducted according to comorbid factors. Patients with esophageal cancer did not show lower odds for the duration of statin prescription in the overall study population (OR = 1.30, 95% CI = 1.03-1.65, p = 0.027 for 180 to 545 days and OR = 1.29, 95% CI = 1.08-1.55, p = 0.006 for >545 days). Subgroups of nonsmokers, past and current smokers, alcohol consumption ≥ 1 time a week, SBP < 140 mmHg and DBP < 90 mmHg, fasting blood glucose ≥ 100 mg/dL, total cholesterol ≥ 200 mg/dL, CCI score = 0, and nondyslipidemia history demonstrated low odds for the duration of statin prescription. Both types of statins, hydrophilic and lipophilic statins, were not related to a lower rate of esophageal cancer. The mortality of esophageal cancer was not associated with the duration of statin prescription. A subgroup with total cholesterol ≥ 200 mg/dL showed lower odds of statin prescription for mortality of esophageal cancer. The duration of statin prescription was not related to a lower rate or mortality of esophageal cancer in the adult Korean population.

Exploring the Link between Chronic Kidney Disease and Alzheimer's Disease: A Longitudinal Follow-Up Study Using the Korean National Health Screening Cohort

Chronic kidney disease (CKD) and Alzheimer's disease (AD) are common chronic diseases in the elderly population. Although a relationship between CKD and the occurrence of AD has been proposed, previous research results have been disputed, and further investigation is necessary to confirm this relationship. In this longitudinal follow-up study, we examined data from the Korean National Health Insurance Service-Health Screening Cohort, consisting of 15,756 individuals with CKD and 63,024 matched controls aged ≥40 years who received health check-ups between 2002 and 2019. Overlap-weighted Cox proportional hazard regression models were exploited to calculate hazard ratios (HRs) for the association between CKD and AD. During the monitoring period, individuals with CKD had a greater incidence of AD than those without CKD (15.80 versus 12.40 per 1000 person years). After accounting for various factors, CKD was significantly associated with a 1.14-fold increased likelihood of developing AD, with a 95% confidence interval ranging from 1.08 to 1.20. In subgroup analysis, this relationship persisted irrespective of age (≥70 or <70), sex, income, smoking status, alcohol consumption, place of residence, or fasting blood glucose level. Additionally, the association between CKD and AD was still evident among patients who were overweight or obese, those with normal blood pressure or cholesterol levels, and those without any other health conditions or with a CCI score of ≥2. These results suggest that CKD could increase the probability of developing AD in the Korean adult population irrespective of demographic or lifestyle conditions. This may make it challenging to predict AD in patients with CKD, emphasizing the importance of frequent AD screening and management.

Comparison of the Concordance of Allergic Diseases between Monozygotic and Dizygotic Twins: A Cross-Sectional Study Using KoGES HTS Data

Several epidemiological studies have demonstrated that genetic and environmental factors contribute to the development of allergic diseases. However, there is limited information on these factors in the Korean population. This study investigated the importance of genetic and environmental factors in allergic diseases, such as allergic rhinitis, asthma, allergic conjunctivitis, or atopic dermatitis, by comparing the disease incidence in Korean adult monozygotic and dizygotic twins. This cross-sectional study utilized data from 1296 twin pairs, including 1052 monozygotic and 244 dizygotic twins, aged over 20 years, from the Korean Genome and Epidemiology Study (2005-2014). The study utilized binomial and multinomial logistic regression models to compute odds ratios of disease concordance. The concordance rate (92%) of the presence or absence of atopic dermatitis in monozygotic twins was slightly higher than that in dizygotic twins (90.2%), which only had a borderline significance (p = 0.090). The concordance rates of other allergic diseases within monozygotic twins were lower compared to dizygotic twins (asthma, 94.3% vs. 95.1%; allergic rhinitis, 77.5% vs. 78.7%; allergic conjunctivitis, 90.6% vs. 91.8%), of which the differences were not statistically significant. Monozygotic twins had a higher proportion of cases in which both siblings had allergic diseases than dizygotic twins (asthma, 1.1% vs. 0.0%; allergic rhinitis, 6.7% vs. 3.3%; atopic dermatitis, 2.9% vs. 0.0%; allergic conjunctivitis, 1.5% vs. 0.0%), of which the differences were also not statistically significant. In conclusion, our results appear to indicate the relative importance of environmental factors over genetic factor in the development of allergic diseases in Korean adult monozygotic twins.

Possible Incidental Parkinson's Disease following Asthma: A Nested Case-Control Study in Korea

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.

Association between Chronic Kidney Disease and Sudden Sensorineural Hearing Loss: A Longitudinal Follow-Up Studies Using ICD-10 Codes in a National Health Screening Cohort

This study aims to investigate the association between chronic kidney disease (CKD) and sudden sensorineural hearing loss (SSNHL) using a population-based cohort study. We used data from the Korean National Health Insurance Service-Health Screening Cohort. Participants were selected based on diagnosis and treatment codes, and CKD participants were 1:4 matched with control participants. Covariates, including demographic and lifestyle factors, and comorbidities were considered in the analysis. We calculated the incidence rate and hazards ratio of SSNHL. A total of 16,713 CKD participants and 66,852 matched controls were enrolled. The CKD group had a higher incidence rate of SSNHL compared to the control group at 2.16 and 1.74 per 1000 person-years, respectively. The CKD group exhibited a higher risk for SSNHL compared to the control group with adjusted HR 1.21. In the subgroup analysis, the presence of cardiovascular risk factors was associated with a diminished effect of CKD on the risk of developing SSNHL. This study provides strong evidence of an association between CKD per se and an increased risk of SSNHL even after adjusting for various demographic and comorbidity factors. The findings suggest that CKD patients may require more comprehensive monitoring for hearing loss.

Association between Gallstone Disease and Statin Use: A Nested Case-Control Study in Korea

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.

Can we safely place the distal volar locking plate screws into the subchondral zone of a distal radius fracture using a 45° supination oblique view under fluoroscopic guidance?

INTRODUCTION

Careful distal locking screw insertion into the subchondral zone is necessary to obtain proper mechanical strength of unstable distal radius fractures using volar locking plating. However, subchondral zone screw insertion increases the risk of intra-articular screw penetration, which may remain unrecognized during surgery due to complex distal radial anatomy. The purpose of this study was to evaluate the role of fluoroscopic guidance with a 45° supination oblique view technique for placing distal screws into the subchondral zone during volar locking plating for unstable distal radius fractures and to explore the factors associated with poor screw placement.

METHODS

We retrospectively analyzed 171 wrists of 169 patients treated with variable-angle volar locking plates for unstable radius fractures. The subchondral zone was defined as the metaphyseal area within 4 mm of the articular margin of the distal radius. The location of the distal locking screws and radiographic parameters, including the teardrop angle, were measured using computed tomography scans and X-rays. Clinical and radiographic factors were examined to determine their possible associations with screw placement failure.

RESULTS

Of 581 distal screws inserted, 559 screws (96.2%) were inserted into the subchondral zone and 17 screws into the metaphyseal zone (2.9%). Five screws (0.7%) in three wrists showed intra-articular placement: four screws were placed into the lunate fossa and one into the scaphoid fossa. These three wrists also exhibited significantly reduced teardrop angles. The distal screws were significantly closer to the joint line in the lunate fossa than the scaphoid fossa (1.9 ± 0.9 mm vs. 2.8 ± 1 mm, P < 0.000).

CONCLUSION

The 45° supination oblique view technique is a useful fluoroscopic guiding technique for accurate and safe distal screw placement in the subchondral zone in volar locking plate fixation for distal radial fractures. However, a decreased teardrop angle or extended lunate fossa should be corrected before distal screw insertion to avoid intra-articular screw placement.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

The Risk of BPPV, Meniere's Disease, and Vestibular Neuronitis in Patients with Gout: A Longitudinal Follow-Up Study Using a National Health Screening Cohort

This study evaluated the impact of pre-existing gout on the occurrence of benign paroxysmal positional vertigo (BPPV), Meniere’s disease, and vestibular neuronitis, with the goal of identifying novel associations of gout with other comorbid diseases. The 2002−2019 Korean National Health Insurance Service Health Screening Cohort data were retrospectively analyzed. 23,827 patients with gout were matched to 95,268 controls without gout for age, sex, income, region of residence, and index date. The occurrence of BPPV, Meniere’s disease, and vestibular neuronitis was evaluated in both groups. The hazard ratios (HRs) of gout for BPPV, Meniere’s disease, and vestibular neuronitis were calculated using a stratified Cox proportional hazard model. Participants with gout demonstrated a 1.13-fold higher risk of BPPV (95% CI, 1.06−1.21, p < 0.001) and a 1.15-fold higher risk of Meniere’s disease (95% CI, 1.15−1.37, p < 0.001) than the matched control group. However, the HR for vestibular neuronitis was not significantly higher in the gout group (adjusted HR = 1.06, 95% CI, 0.93−1.21, p = 0.391). A previous history of gout was related to a higher risk of BPPV and Meniere’s disease. Additional studies are necessary to elucidate the mechanism underlying the relationship between gout and comorbid diseases such as BPPV and Meniere’s disease.

The association between hyperuricemia and cardiovascular disease history: A cross-sectional study using KoGES HEXA data

This cross-sectional study examines the association between hyperuricemia and cardiovascular diseases (CVDs). Data from the Korean Genome and Epidemiology Study from 2004 to 2016 were analyzed. Among the 173,209 participants, we selected 11,453 patients with hyperuricemia and 152,255 controls (non-hyperuricemia). We obtained the history of CVDs (stroke and ischemic heart disease [IHD]) from all participants. Crude and adjusted odds ratios (aORs) (age, income group, body mass index, smoking, alcohol consumption, anthropometry data, and nutritional intake) for CVDs were analyzed using a logistic regression model. Participants with hyperuricemia reported a significantly higher prevalence of stroke (2.4% vs 1.3%) and IHD (5.6% vs 2.8%) than controls did (P < .001). Participants with hyperuricemia had a significantly higher aOR for CVD than the controls. The aOR of hyperuricemia for stroke was 1.22 (95% confidence interval = 1.07-1.39, P = .004). When analyzed by subgroup according to age and sex, this result was only persistent in women. The aOR of hyperuricemia for IHD was 1.45 (95% confidence interval = 1.33-1.59, P < .001). In the subgroup analyses, the results were similar, except in young men. Hyperuricemia was significantly associated with CVD in the Korean population.

Associations between proton pump inhibitors and Alzheimer’s disease: a nested case–control study using a Korean nationwide health screening cohort

Background

Safety concerns against the use of proton pump inhibitors (PPIs) based on the risk of dementia, especially Alzheimer’s disease (AD), remain controversial. Here, we investigated the likelihood of AD depending on previous PPI exposure, use duration, and PPI generation.

Methods

This nested case–control study comprised 17,225 AD patients who were 1:4 matched with 68,900 controls for age, sex, income, and region of residence from Korean National Health Insurance Service-Health Screening Cohort data between 2002 and 2015 using propensity-score matching method. Conditional and unconditional logistic regression analyses were used to evaluate the effects of previous PPI use on AD adjusting for multiple covariates.

Results

Prior PPI use increased likelihood for AD in current and past PPI users (adjusted odds ratio 1.36 [95% confidence interval (CI) = 1.26–1.46] and 1.11 [95% CI = 1.04–1.18], respectively). Participants with either < 30 days, 30–90 days, or > 90 days of PPI prescription showed higher odds for AD (1.13 [95% CI = 1.07–1.19]; 1.18 [95% CI = 1.10–1.27]; 1.26 [95% CI = 1.16–1.36], respectively). Participants with either 1st-generation or 2nd-generation PPIs demonstrated higher incidences of AD in those with < 30 days (1.14 [95% CI = 1.07–1.22] and 1.13 [95% CI = 1.05–1.22], respectively), 30–90 days (1.19 [95% CI = 1.09–1.30] and 1.17 [95% CI = 1.05–1.29], respectively), or > 90 days (1.18 [95% CI = 1.07–1.30] and 1.27 [95% CI = 1.14–1.43], respectively) of prescription.

Conclusions

Prior PPI use, regardless of current or past exposure, duration of use, or use of 1st- or 2nd-generation PPIs, may increase likelihood of AD, providing supportive evidence of previous pharmacoepidemiologic studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-022-01032-5.

Changes in mean and variance of ophthalmic disease incidences during COVID-19 pandemic in Korea

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.

Comparison of the Concordance of Cardiometabolic Diseases and Physical and Laboratory Examination Findings between Monozygotic and Dizygotic Korean Adult Twins: A Cross-Sectional Study Using KoGES HTS Data

This study investigated the contribution of genetic and environmental factors to cardiometabolic diseases (CMDs) by comparing disease concordance in monozygotic and dizygotic twins. This cross-sectional study analyzed 1294 (1040 monozygotic and 254 dizygotic) twin pairs (>20 years) based on the Korean Genome and Epidemiology Study data (2005−2014). The odds ratios of disease concordance were calculated using binomial and multinomial logistic regression models. The occurrence of CMDs (hypertension, hyperlipidemia, type 2 diabetes, cerebral stroke, transient ischemic attack, and ischemic heart disease) and related physical and laboratory levels did not differ between the monozygotic and dizygotic twin groups. The odds for concordance of the presence/absence of CMDs and the likelihood of incident CMD within monozygotic twins were comparable to that of dizygotic twins. The absolute differences in hemoglobin A1c, insulin, low- and high-density lipoprotein cholesterol, total cholesterol, triglycerides, and systolic blood pressure were lower in monozygotic twins than in dizygotic twins. Absolute differences in fasting glucose and diastolic blood pressure did not differ between groups. Although baseline levels of several laboratory parameters related to CMD showed a strong likelihood of heritability in monozygotic twins, CMD phenotype appears to be largely affected by environmental factors.

Association between Migraines and Prior Proton Pump Inhibitor Use: A Nested Case-Control Study Using a National Health Screening Cohort

The effect of proton pump inhibitor (PPI) use on migraine risk remains controversial. We explored the odds of migraines in relation to prior PPI use and treatment duration. Data from the Korean National Health Insurance Service-Health Screening Cohort (2002−2015) were analyzed in this nested case-control study involving 28,159 participants with incident migraines and 112,636 controls (1:4 matched by sex, age, income, and residential region). The baseline covariates were balanced by performing propensity score overlap weighting-based adjustments, and the effect of prior PPI use (past vs. current) and treatment duration (<30 and 30−365 days vs. ≥365 days) on incident migraines was evaluated using logistic regression. In past and current PPI users, prior PPI use raised the likelihood of migraines (adjusted odds ratio [95% confidence interval]: 2.56 [2.36−2.79] and 4.66 [4.29−5.06], respectively). Participants who used PPI for <30, 30−365, or ≥365 days exhibited high odds of migraines (2.49 [2.29−2.72], 4.41 [4.05−4.79], and 4.14 [3.77−4.54], respectively). Incident migraines with or without aura also increased independently of PPI use history or duration. In summary, prior PPI use, irrespective of the elapsed time since use and the duration of use, is possibly associated with incident migraines with or without aura.

The Reciprocal Relationship between Osteoporosis and Renal Stones

Previous studies have proposed an association between osteoporosis and renal stones. The current analyses intended to investigate the bidirectional relationship between osteoporosis and renal stones. The ≥40-year-old population in the National Health Insurance Service-Health Screening cohort (2002-2015) was analyzed. In study I, 67,811 patients with osteoporosis and 67,811 control I participants were matched. The hazard ratio (HR) of osteoporosis for renal stones was calculated using stratified Cox proportional hazard models. In study II, 25,261 patients with renal stones and 101,044 control II participants were matched. The HR of renal stones for osteoporosis was estimated using stratified Cox proportional hazard models. In study I, 3.4% (2276/67,811) of osteoporosis patients and 2.5% (1696/67,811) of control I participants had renal stones. Osteoporosis patients had a 1.36 times higher HR for renal stones than control I participants (95% confidence intervals [CI] = 1.28-1.45). In study II, 9.2% (2319/25,261) of renal stone patients and 7.6% (7658/101,044) of control II participants had osteoporosis. Renal stone patients had a 1.26 times higher HR for osteoporosis than control II participants (95% CI = 1.21-1.32). Adults with osteoporosis had a higher risk of renal stones. Moreover, adults with renal stones had a higher risk of osteoporosis.

Incidence of Asthma, Atopic Dermatitis, and Allergic Rhinitis in Korean Adults before and during the COVID-19 Pandemic Using Data from the Korea National Health and Nutrition Examination Survey

The prevalence of allergic diseases has been increasing globally prior to COVID-19. The pandemic resulted in changes in lifestyle and personal habits such as universal mask-wearing and social distancing. However, there is insufficient information on the impact of the COVID-19 pandemic on the prevalence of allergic conditions such as asthma, atopic dermatitis, and allergic rhinitis. We analyzed the incidence rate for self-reported and doctor-diagnosed cases of allergic diseases of asthma, atopic dermatitis, and allergic rhinitis. A total of 15,469 subjects were registered from a national cohort dataset of the National Health and Nutrition Examination Survey. Using multiple logistic regression analysis, we calculated the adjusted odds ratio (OR) for each disease in 2020 compared to 2019. Subgroup analyses were performed according to age and sex. There were no statistically significant differences between the incidence of doctor-diagnosed and current allergic diseases in 2019 and 2020 (asthma, p = 0.667 and p = 0.268; atopic dermatitis, p = 0.268 and p = 0.973; allergic rhinitis, p = 0.691 and p = 0.942, respectively), and subgroup analysis showed consistent results. Among the Korean population from 2019 to 2020, the incidence of the allergic diseases asthma, atopic dermatitis, and allergic rhinitis did not decrease as expected.

Changes in Otorhinolaryngologic Disease Incidences before and during the COVID-19 Pandemic in Korea

This study aimed to investigate the change in the incidence and variance of otorhinolaryngologic diseases during the coronavirus disease 19 (COVID-19) pandemic. The entire Korean population (~50 million) was evaluated for the monthly incidence of 11 common otorhinolaryngologic diseases of upper respiratory infection (URI), influenza, acute tonsillitis, peritonsillar abscess, retropharyngeal and parapharyngeal abscess, acute laryngitis and bronchitis, stomatitis and related lesions, acute sinusitis, rhinitis, otitis media, and dizziness from January 2018 through March 2021 using the International Classification of Disease (ICD)-10 codes with the data of the Korea National Health Insurance Service. The differences in the mean incidence of 11 common otorhinolaryngologic diseases before and during COVID-19 were compared using the Mann-Whitney U test. The differences in the variance of incidence before and during COVID-19 were compared using Levene's test. The incidence of all 11 otorhinolaryngologic diseases was lower during COVID-19 than before COVID-19 (all p < 0.05). The variations in disease incidence by season were lower during COVID-19 than before COVID-19 for infectious diseases, including URI, influenza, acute tonsillitis, peritonsillar abscess, retropharyngeal and parapharyngeal abscess, acute laryngitis and bronchitis, acute sinusitis, and otitis media (all p < 0.05), while it was not in noninfectious diseases, including stomatitis, rhinitis, and dizziness. As expected, the incidences of all otorhinolalryngolgic diseases were decreased. Additionally, we found that seasonal variations in infectious diseases disappeared during the COVID-19 pandemic, while noninfectious diseases did not.

Comparison of Concordance of Peptic Ulcer Disease, Non-Adenomatous Intestinal Polyp, and Gallstone Disease in Korean Monozygotic and Dizygotic Twins: A Cross-Sectional Study

Epidemiological studies have suggested the role of multiple genetic and environmental factors in the development of non-neoplastic gastrointestinal (GI) diseases; however, little information is available on these factors in the Korean population. Therefore, this cross-sectional study explored the effect of these factors by analyzing the concordance of several benign GI disorders in 525 monozygotic twins compared to that in 122 dizygotic twins aged >20 years from the Healthy Twin Study data of the Korean Genome and Epidemiology Study (2005-2014). Chi-square test, Wilcoxon rank-sum, and binomial and multinomial logistic regression models were used for statistical analysis. There was lack of concordance of gastric/duodenal ulcers and cholelithiasis/cholangitis between monozygotic twins compared to that in dizygotic twins, suggesting that environmental factors may mediate those concordant disease expressions in monozygotic twins. The concordance of intestinal polyps in monozygotic twins was 32% lower than that in dizygotic twins (p = 0.028), indicating that the effect of genetic factors on the risk for intestinal polyp development may be low. In conclusion, the lack or low concordance of several benign GI diseases between monozygotic and dizygotic twin groups suggests the relative importance of environmental factors, indicating that these are preventable diseases.

Obesity Is Positively Associated and Alcohol Intake Is Negatively Associated with Nephrolithiasis

The current research investigated the impacts of smoking, alcohol consumption, and obesity on the development of nephrolithiasis. We included ≥40-year-old Koreans from the Korean National Health Insurance Service-Health Screening Cohort. A total of 28,395 nephrolithiasis patients were compared with 113,580 control participants. Previous histories of smoking, alcohol consumption, and obesity were examined before the presence of nephrolithiasis. Conditional logistic regression analysis was performed to estimate the odds ratios (ORs) of smoking, alcohol consumption, and obesity for nephrolithiasis. Further analyses were conducted, according to age, sex, smoking, alcohol consumption, and obesity. The current smoking status was not linked with the presence of nephrolithiasis. Alcohol consumption was linked with a lower likelihood of the presence of nephrolithiasis (adjusted OR (aOR) = 0.89, 95% confidence intervals (CI) = 0.86−0.92, p < 0.001). Being obese was associated with a greater likelihood of the presence of nephrolithiasis ((95% CI) = 1.27 (1.22−1.31) < 1.42 (1.37−1.46) < 1.59 (1.47−1.71) for overweight < obese I < obese II). The relation of alcohol consumption and obesity with nephrolithiasis was consistent in the subgroups. The presence of nephrolithiasis was positively linked with obesity and negatively linked with alcohol consumption.

Association between Urolithiasis and History Proton Pump Inhibitor Medication: A Nested Case-Control Study

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.

Association between metabolic syndrome and osteoporosis among adults aged 50 years and older: using the National Health Information Database in South Korea

This study aimed to examine the association between a history of metabolic syndrome (MetS) and osteoporosis with specific characteristics. The results showed that MetS was inversely associated with osteoporosis. In contrast, MetS was positively associated with osteoporosis in both obese men and postmenopausal obese women.

PURPOSE

Although several previous studies have investigated the association between MetS and osteoporosis, their findings remain controversial. This study aimed to examine the association between a MetS history and osteoporosis using a subset of data from a large, long-term, national database.

METHODS

This nested case-control study used the National Health Information Database (NHID) of the Korea National Health Insurance Service (NHIS) from 2009 to 2017. Osteoporosis (n = 459,771) and control (n = 459,771) participants were matched in a 1:1 ratio by age, gender, income, and region of residence. MetS was defined based on the modified National Cholesterol Education Program-Adult Treatment Panel III criteria. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for osteoporosis in patients with MetS and its components were analyzed using logistic regression. Subgroup analyses were performed according to the combination of gender, menopausal status, and obesity status.

RESULTS

The adjusted OR (95% CI) for osteoporosis in patients with MetS was 0.95 (0.94-0.96). This finding was consistent with the subgroup analyses in normal weight men, premenopausal (pre-MP) women with all obesity statuses, and postmenopausal (post-MP) underweight and normal weight women. In contrast, the opposite was observed for obese men (OR = 1.05, 95% CI = 1.01-1.09) and post-MP obese women (OR = 1.05, 95% CI = 1.01-1.08).

CONCLUSION

This study results suggested that MetS was associated with a low occurrence of osteoporosis. In contrast, MetS was associated with a high occurrence of osteoporosis in both obese men and post-MP obese women.

Differences in Nutritional Intake, Total Body Fat, and BMI Score between Twins

The present study aimed to investigate the coincidence of obesity and nutritional intake in monozygotic twins compared to dizygotic twins. The data from the Korean Genome and Epidemiology Study (KoGES) from 2005 through 2014 were analyzed. Participants ≥ 20 years old were enrolled. The 1006 monozygotic twins and 238 dizygotic twins were analyzed for differences in self-reported nutritional intake, total body fat, and body mass index (BMI) using a linear regression model. The estimated values (EV) with 95% confidence intervals (95% CI) of the difference in dietary intake, total body fat, and BMI score were calculated. The monozygotic twin group and the dizygotic twin group showed similar differences in nutritional intake, DEXA fat, and BMI (all p > 0.05). The differences in nutritional intake of total calories and carbohydrates were lower in the monozygotic twin group than in the dizygotic twin group (all p < 0.05). The differences in total body fat were lower in monozygotic twins than in dizygotic twins (adjusted EV = 2427.86 g, 95% CI = 1777.19−3078.53 and adjusted EV = 1.90%, 95% CI = 1.33−2.46). Monozygotic twins had more similar dietary habits for total calories and carbohydrate intake. Other nutritional factors did not show differential similarity between monozygotic and dizygotic twins. Total body fat was more concordant in monozygotic twins.

Association between gastric cancer and the family history of gastric cancer: a cross-sectional study using Korean Genome and Epidemiology Study data

OBJECTIVE

The risk of gastric cancer based on a family history of gastric cancer remains unclear. The purpose of this study was to investigate the relationship between gastric cancer and family history of gastric cancer within a large cohort in Korea.

METHODS

In total 211 708 participants were recruited in the Korean Genome and Epidemiology Study during 2001-2013, and divided into a group with a self-reported personal history of gastric cancer ( n  = 930) and a 1:40 matched control group ( n  = 37 200). We examined the family history of gastric cancer in first-degree relatives for cross-sectional analysis. Logistic regression was used to estimate the odds ratios (ORs) of gastric cancer according to family history, using four models that were adjusted for different confounding variables, including the interaction among a family history of gastric cancer.

RESULTS

After matching the two groups for age and sex, the gastric cancer group had a significantly higher proportion of family history in each relative than the controls ( P  < 0.001). In the adjusted model, the ORs [95% confidence interval (CI)] for gastric cancer with a history of an affected father, mother and sibling were 1.80 (1.38-2.34), 1.95 (1.42-2.69) and 2.98 (2.31-3.83), respectively, compared with those in the control group. There was no statistically significant interaction among a family history of gastric cancer in each relative.

CONCLUSION

A history of gastric cancer in siblings, among first-degree relatives, is strongly associated with an increased risk of gastric cancer. Regular follow-up and early treatment are recommended for those with a family history of gastric cancer.

Association between Benign Paroxysmal Positional Vertigo and Previous Proton Pump Inhibitor Use: A Nested Case-Control Study Using a National Health Screening Cohort

The present nested case−control study evaluated the impact of previous proton pump inhibitor (PPI) prescription on the risk of benign paroxysmal positional vertigo (BPPV). A ≥40-year-old Korean population was included. A total of 34,441 patients with BPPV was matched with 137,764 comparison participants for demographic and socioeconomic factors. Previous histories of PPI use and PPI prescription dates were compared between the BPPV and comparison groups. The odds ratios (ORs) with 95% confidence intervals (CIs) of PPI use for BPPV were calculated using a logistic regression. The demographic and socioeconomic factors and comorbidities were adjusted in the adjusted model. Both current and past PPI users were associated with higher odds for BPPV than non-PPI users (adjusted OR (aOR) = 3.57, 95% CI = 3.33−3.83, and p < 0.001 for current PPI users and aOR = 1.76, 95% CI = 1.64−1.89, and p < 0.001 for past PPI users). In addition, longer dates of PPI use were related to higher odds for BPPV (aOR (95% CI) = 1.95 [1.81−2.10] for ≥1 day and <30 days of PPI prescription, <2.88 [2.68−3.10] for ≥30 days and <365 days of PPI prescription, and <3.45 [3.19−3.73] for ≥365 days of PPI prescription). PPI use was linked with an elevated risk of BPPV in the adult population. The odds for BPPV were higher in patients with a longer duration of PPI use.

Depression, Stress, and Suicide in Korean Adults before and during the COVID-19 Pandemic Using Data from the Korea National Health and Nutritional Examination Survey

This study investigated changes in the prevalence of depression, stress, and suicidal attempts during the COVID-19 pandemic. The ≥19-year-old population in the Korea National Health and Nutrition Examination Survey in 2019 and 2020 was included. The histories of depression, stress, and suicidal attempts were compared between the 2019 and 2020 cohorts using multiple logistic regression analysis with complex sampling. The prevalence of depression was not significantly different between the 2019 and 2020 groups (4.1% vs. 4.5%, p = 0.326). The prevalence of stress and suicide attempts was also not significantly different between groups (all p > 0.05). The rates of depression, stress, and suicide attempts were not associated with the 2020 group compared to the 2019 group (all p > 0.05). The 19- to 39-year-old group in the 2020 group indicated a higher rate of depression (diagnosed by physicians) than the 19- to 39-year-old group in the 2019 group (adjusted odds ratio = 1.58, 95% confidence intervals = 1.00−2.50, p = 0.049). The risks of depression, stress, and suicidal attempts were not related to the COVID-19 pandemic in Korean adults. A young adult population demonstrated an increased risk of depression associated with the COVID-19 pandemic.

Analysis of Nasal Foreign Bodies in South Korea: Over 10-Year Experience

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.

Physical Activity and Sedentary Time in Korean Adults before and during the COVID-19 Pandemic Using Data from the Korea National Health and Nutritional Examination Survey

Several recent studies suggested reduced physical activity (PA) related to the COVID-19 pandemic without consensus. This study investigated the changes in PA and sedentary time during the COVID-19 pandemic compared to before the COVID-19 era. The Korea National Health and Nutrition Examination Survey 2019 and 2020 were used. The ≥19-year-old population was examined in 2019 and 2020 for time spent engaging in high- and moderate-intensity PA and sedentary time. Based on the recommended level of PA by the World Health Organization, ≥75 min/wk of high PA and ≥150 min/of moderate PA were classified. A sedentary time of ≥120 min/d was selected. Multiple logistic regression analysis with complex sampling was conducted for ≥75 min/wk of high PA, ≥150 min/wk of moderate PA, and ≥120 min/d of sedentary time in the 2020 group compared to the 2019 group. The ≥75 min/wk high PA was not lower in the 2020 group than in the 2019 group (adjusted odds ratio (aOR) = 0.96, 95% confidence intervals (95% CIs) = 0.79–1.18, P = 0.696). The ≥150 min/wk of moderate PA was also not lower in the 2020 group (aOR = 1.12, 95% CI = 0.94–1.32, p = 0.201). However, the ≥150 min/wk of moderate PA in the female group was higher in the 2020 group than in the 2019 group (aOR = 1.29, 95% CI = 1.01–1.65, p = 0.042). Sedentary time ≥ 120 min/d was lower in the 2020 group (aOR = 0.35, 95% CI = 0.17–0.72, p = 0.005). This association was consistent in the 19–39-year-old and female group. In conclusion, during the COVID-19 pandemic, high and moderate PA were not decreased in Korean adults, while sedentary time was reduced.

Changes in the Mean and Variance of the Numbers of Medical Visits for Allergic Diseases before and during the COVID-19 Pandemic in Korea

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.

Changes in the Incidence Rates of Gastrointestinal Diseases Due to the COVID-19 Pandemic in South Korea: A Long-Term Perspective

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.

Associations Between Asthma Diagnosis/Asthma Exacerbation and Previous Proton-Pump Inhibitor use: A Nested Case-Control Study Using a National Health Screening Cohort

Background: Proton-pump inhibitors (PPIs) block acid secretion from gastric parietal cells; however, recent studies have reported that PPIs have antioxidant and anti-inflammatory properties in various cells. Newer PPIs are stronger inhibitors of acid secretion; however, the anti-inflammatory effects of these drugs have not been assessed. We evaluated anti-inflammatory effect of PPIs on the development of asthma/asthma exacerbation (AE) in a national health screening cohort.

Methods: This case-control study comprised 64,809 participants with asthma who were 1:1 matched with controls from the Korean National Health Insurance Service-Health Screening Cohort. Conditional logistic regression analysis was used to evaluate the effect of previous PPI use on an asthma diagnosis in all participants. Unconditional logistic regression was used to assess the effect of PPI use on AE in participants with asthma. These relationships were estimated in a subgroup analysis according to PPI generation.

Results: Overall, PPI use increased the risk of asthma diagnosis [adjusted odds ratio (aOR) = 1.29, 95% confidence interval (CI) = 1.23–1.35, p < 0.001]. Use of the first-generation PPIs was associated with asthma (aOR = 1.34, 95% CI = 1.18–1.52, p < 0.001), while use of second-generation PPIs was not (aOR = 0.97, 95% CI = 0.82–1.15, p = 0.748). In contrast, overall PPI use decreased the risk of AE in participants with asthma (aOR = 0.79, 95% CI = 0.75–0.84, p < 0.001), although this effect was observed only for second-generation PPIs (aOR = 0.76, 95% CI = 0.65–0.89, p = 0.001).

Conclusion: PPI use increased the risk for subsequent asthma diagnosis. However, this effect was confined to first-generation PPIs. Second-generation PPIs decreased the risk of AE.