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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]

Tonsillectomy has been suggested as a potential intervention to resolve psoriasis; however, its preventive effects on the development of psoriasis remain unclear. This study aimed to investigate the risk of developing late-onset psoriasis among a Korean adult population who had undergone tonsillectomy. Data from the Korean National Health Insurance Service-Health Screening Cohort between 2002 and 2019 were utilized. Out of a total of 514,866 participants, 1082 participants aged 40 years or older who had undergone tonsillectomy were matched with 4328 control participants using overlap weighting adjustment based on the propensity score. The incidence and hazard ratio (HR) of psoriasis were calculated for both tonsillectomy and control groups. The incidence rates of psoriasis were 1.30% in the tonsillectomy group and 1.20% in the control group. The incidence of psoriasis (overlap-weighted HR = 1.08, 95% confidence of interval = 0.69–1.69, and p = 0.732) did not differ significantly between the patients who underwent tonsillectomy and those in the control group. The cumulative probability of developing psoriasis was not different between the two groups (Log-rank test: p = 0.440). These findings were consistent across subgroups divided by age, sex, income, and region of residence. We found that tonsillectomy did not confer a preventive effect on the development of late-onset psoriasis in the Korean adult population. [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]

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. [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]

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]

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. [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 was aimed to compare the risk of pneumonia between patients with chronic rhinosinusitis (CRS) and those without CRS (control) in a Korean population. The population aged 40 years or over was included from the Korean National Health Insurance Service-Health Screening Cohort. Participants with CRS (n = 6393) and controls (n = 25,572) were selected by 1:4 matching for age, sex, income, region of residence, and history of pneumonia for the previous 1 year. The index date (ID) of the controls was set as the treatment date of their matched CRS participants. The incidence of pneumonia after the ID was measured from 2003 to 2015. Simple and multiple linear regressions were performed to calculate estimated values (EVs) and 95% confidence intervals (CIs) for 1-y post-ID pneumonia, 2-y post-ID pneumonia, and 3-y post-ID pneumonia in CRS participants compared to controls. Statistical significance was noted in the 3-y post-ID period (EV = 0.017, 95% CI = 0.002–0.031, P = 0.030). In the subgroup analyses according to age and sex, statistical significance was seen in the younger age group (< 60 years old) in the 3-y post-ID period and in the female group in the 1-y and 3-y post-ID periods. This study revealed an increased risk for pneumonia following a diagnosis of CRS. [ABSTRACT FROM AUTHOR]

Since a potential link between statins and the risk of adverse chronic periodontitis (CP) has been raised, we aimed to validate the association between statin use and the incidence of CP using nationwide cohort data. This longitudinal follow-up study included 169,381 patients prescribed statins who were matched with an equal number of controls using propensity scores from the Korean National Health Insurance Service-Health Screening Cohort database (2002–2015). A Cox proportional hazard model was used to assess the occurrence of CP following statin use after adjusting for multiple covariates. The occurrence of CP was significantly higher in patients who had long-term use (1–3 years, 3–5 years, or > 5 years) than with short-term use (≤ 1 year) of statins. After adjustment, statin users exhibited an occurrence of CP 1.32-fold higher (95% confidence interval 1.30–1.33) than that of the matched nonusers (incidence: 25.0 and 22.0 per 100 person-years, respectively). Subgroup analyses supported the adverse impact of statins on CP independent of age and gender. Statin user odds ratios for developing CP were higher compared to those of nonusers. This was consistent in individuals aged > 40 years in both genders, especially with long-term use. [ABSTRACT FROM AUTHOR]

We evaluated the influence of visual impairment (VI) on income change using the longitudinal database of a Korean National Health Insurance Service cohort. A total of 5292 participants ≥ 40 years old and registered as visually impaired persons were selected at a 1:4 ratio with 45,081 non-VI participants matched for age, sex, and income level. The income level of both the VI and non-VI groups increased over time. In the VI group, the income levels 3, 4 and 5 years were higher than the initial value, while the income levels from 1 through 5 years were increased each year in the non-VI group. The rate of change in income between time and VI were significant. In the subgroup analysis considering age, sex, and severity of VI, the rate of change in income were significant in < 65 years old subgroups. Regarding the severity of VI, a significant interaction was found for the mild-to-moderate VI subgroup. Although both the VI and non-VI groups showed increased income levels over 5 years, the degree of income increase in the VI group was relatively lower than that in the non-VI group. This finding was prominent in the middle-age subgroup. These results strongly suggested that VI induced an income inequality. [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]

The objective of this cross-sectional study was to evaluate the association between periodontitis and glaucoma. This prospective cohort study used epidemiological data from the Korean Genome and Epidemiology Study performed between 2004 and 2016. Among 173,209 participants, 9572 patients with periodontitis and 115,332 controls (nonperiodontitis) were selected. We analysed the history of glaucoma in periodontitis and control participants. The participants were interviewed regarding their history of hypertension, diabetes mellitus, hyperlipidaemia, periodontitis, glaucoma, smoking, and alcohol consumption by trained interviewers. A logistic regression model was created to analyse the odds ratio of having a history of glaucoma among patients with periodontitis. Two-tailed analyses using chi-square and independent t-tests were used for statistical analysis. The adjusted odds ratio of periodontitis as a risk factor for glaucoma was 3.44 (95% confidence interval = 2.99–3.97, p < 0.001). This study demonstrated that glaucoma was associated with periodontitis. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to delineate the causal relationship between Ménière's disease and depression. Design: Two longitudinal follow‐up studies. Main Outcome Measures: The 2002‐2013 Korean National Health Insurance Service‐Health Screening Cohort was used. In study I, Ménière's disease patients were 1:4 matched with the control I group for age group, sex, income group and region of residence, and the occurrence of depression was observed. In study II, the depression patients were 1:4 matched with the control II group for the same variables, and the occurrence of Ménière's disease was observed. The stratified Cox proportional hazard model was used. Subgroup analyses were performed according to age and sex. Results: In study I, 6.9% (420/6044) of the Ménière's disease patients and 3.7% (885/24 176) of the control I participants experienced depression. The adjusted hazard ratio (HR) of Ménière's disease for depression was 1.94 (95% confidence intervals [CI] = 1.73‐2.18, P <.001). In study II, 1.6% (490/31 649) of the depression patients and 1.0% (1240/126 596) of the control II participants were diagnosed with Ménière's disease. The adjusted HR of depression for Ménière's disease was 1.58 (95% CI = 1.43‐1.76, P <.001). All age and sex subgroups demonstrated higher HRs of Ménière's disease for depression (study I) and depression for Ménière's disease (study II). Conclusion: Ménière's disease patients showed an increased likelihood of depression. Conversely, depression patients showed an elevated likelihood of Ménière's disease. [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]

Objective: This study aimed to investigate the risk of sudden sensorineural hearing loss (SSNHL) in Herpes zoster patients from a representative population cohort. Design: A longitudinal follow-up study Study sample: Data were obtained from the Korean National Health Insurance Service-National Sample Cohort for the period from 2002 to 2013. We matched 61,702 subjects in the Herpes zoster group with subjects in a control group (246,808 subjects with no history of Herpes zoster) based on demographic factors (age, sex, income, and region of residence) and medical history (diabetes, dyslipidemia, and hypertension). The crude (simple) and adjusted hazard ratios (HRs) for Herpes zoster with SSNHL were analysed using the Cox-proportional hazard model. Results: Only 0.5% (338/61,364) of the Herpes zoster group and 0.7% (1664/245,144) of the control group showed SSNHL. The Herpes zoster group did not exhibit a higher rate of SSNHL (adjusted HR = 0.81, 95% CI = 0.72–0.91, p < 0.001) than the control group. In subgroup analyses, no age subgroups showed a significant risk of SSNHL in the Herpes zoster group. Conclusions: After adjusting for confounding factors, the risk of SSNHL did not increase in the Herpes zoster group compared with the control group. [ABSTRACT FROM AUTHOR]

Purpose: Focal chronic inflammation or infection is thought to be one of the causes of psoriasis. Few reports on the association between chronic rhinosinusitis (CRS) and psoriasis exist, thus it is poorly defined. This study seeks to investigate the incidence of psoriasis in patients with CRS with reference to a matched control group. Methods: This national cohort study relies on data from Korean Health Insurance Review and Assessment Service—National Sample Cohort (HIRA-NSC), which were entered from 2002 to 2013. A total of 34,219 patients with CRS without nasal polyps was matched with 136,976 controls. The Cox proportional hazard model was used to analyze the crude (simple) and adjusted hazard ratios (HRs) of psoriasis. For subgroup analysis, participants were grouped by age and sex. Results: The risk of psoriasis was higher in the CRS group than in the control group (adjusted HR 1.28, 95% CI 1.12–1.47, P < 0.001). Children, adolescents below 19 years regardless of sex, and old adult men above 60 years are at significantly higher risk for subsequent psoriasis after CRS diagnosis. Conclusion: CRS may increase the risk of psoriasis. [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]

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]

Objective: Hearing impairment has been suggested to increase the risk of falls. However, most previous studies were conducted in an older population without classification of the fracture regions. This study aimed to delineate the risk of each fracture type in all age populations. Methods: The Korean National Health Insurance Service-National Sample Cohort was collected from 2002 to 2013. A total of 4,854 severe hearing-impaired and 1,354 profound hearing-impaired participants were matched for age, group, sex, income group, and region of residence with 19,416 and 5,416 control participants, respectively. The fracture diagnosis was based on the International Classification of Disease (ICD-10) codes as follows: distal radius fracture (S525), hip fracture (S720, S721, S722), and spine fracture (S220, S32). Crude (simple) and adjusted hazard ratios (HRs) for each fracture associated with severe or profound hearing impairment were analyzed using the Cox proportional hazard model. Results: The severe hearing-impaired group had an increased risk of distal radius fracture, hip fracture, and spine fracture compared with the control group (adjusted HR = 1.67, 95% CI = 1.38–2.03, P < 0.001 for hip fracture). The profound hearing-impaired group had an increased risk of hip and spine fracture (adjusted HR = 2.21, 95% CI = 1.44–3.39, P < 0.001 for hip fracture). Conclusion: The risk of distal radius fracture, hip fracture, and spine fracture was increased in the severe hearing-impaired group compared with the control group. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to evaluate the association between thyroid cancer and breast cancer. Methods: Data from the Korean National Health Insurance Service-Health Screening Cohort were collected from 2002 to 2013. In study I, 3949 thyroid cancer participants were 1:4 matched with 15,796 control I participants, and hazard ratios (HRs) with 95% confidence intervals (CIs) for breast cancer were evaluated using a stratified Cox proportional hazard model. In study II, 3308 breast cancer participants were 1:4 matched with 13,232 control II participants, and HRs with 95% CIs for thyroid cancer were assessed in the same way as in study I. In the subgroup analyses, associations were analyzed according to radioactive iodine (RAI) treatment and age (<60 years old and ≥60 years old). Results: The adjusted HR for breast cancer in the thyroid cancer group was 1.64 (95% CI = 1.13–2.39, p = 0.010). The adjusted HR for thyroid cancer in the breast cancer group was 1.91 (95% CI = 1.47–2.49, p < 0.001). In the subgroup analyses, the groups that were older and not treated with RAI treatment showed consistent results in study I, and the younger and older groups showed consistent results in study II. Conclusions: Based on this cohort study, breast and thyroid cancer have a reciprocal positive association. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the impact of pre-existing rheumatoid arthritis (RA) on the occurrence of Meniere's disease (MD). The 2002–2015 Korean National Health Insurance Service—Health Screening Cohort data were retrospectively analyzed. A total of 3038 participants with RA were matched with 12,152 control participants for demographic factors. The occurrence of MD was evaluated in both the RA and control groups. The hazard ratios (HRs) of RA for participants with MD were calculated using a stratified Cox proportional hazard model. Additionally, subgroup analyses were conducted. The rate of MD was not different between the RA and control groups (1.5% vs. 1.3%, standardized difference = 0.01). The HR was not higher in the RA group than in the MD group (adjusted HR = 1.03, 95% confidence interval = 0.73–1.44, p = 0.885). A higher HR of RA for participants with MD was found in the ≥60-year-old subgroup in the crude model but not in the adjusted model. An association between RA and MD was not found in any of the other subgroups. A previous history of RA was not related to an increased risk of MD. [ABSTRACT FROM AUTHOR]

We evaluated the incidence of temporomandibular disorder (TMD) in patients with rheumatoid arthritis (RA) and examined the association between TMD and RA, through longitudinal follow-up. Population data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2015 was used. From 514,866 subjects, 3122 with RA were matched with 12,488 controls in a 1:4 ratio. The crude and adjusted models (for obesity, smoking, alcohol consumption, blood pressure, blood glucose, total cholesterol, and Charlson Comorbidity Index scores) were calculated. Chi-square tests, Kaplan-Meier (KM) analysis, and two-tailed analyses were used for statistical analysis. Stratified Cox proportional hazard models were used to assess the hazard ratios (HR) and 95% confidence intervals (CI) for TMD in the RA group, compared to those in the control group. The adjusted HR for TMD in RA was 2.52 (95% CI = 1.70–3.74), compared to the control group. The results were consistent with the subgroup analyses, according to age and sex, except in men older than 60 years of age. KM analysis showed similar results. Hence, we found that patients with RA have a higher risk of TMD, and should be observed for symptoms of the initial stage of TMD to prevent the risk of aggravation. [ABSTRACT FROM AUTHOR]

This study compared the risk of chronic periodontitis (CP) between chronic rhinosinusitis (CRS) and non-chronic rhinosinusitis (control) patients using a national cohort dataset from the Korean Health Insurance Review and Assessment Service. CRS (n = 5951) and control participants (n = 23,804) were selected after 1:4 ratio matching for age, sex, income, region of residence, and preoperative CP visits. Postoperative CP visits were measured between 2002 and 2015. The margin of equivalence of the difference between the CRS and control groups was set between −0.5 and 0.5. Statistical significance was noted in the post-index date (ID) of the third, fourth, and fifth year periods. In subgroup analyses according to age and sex, statistical significance was observed in 40–59-year-old males in post-ID third, fourth, and fifth year periods, ≥60-year-old males in post-ID third and fourth year periods, and ≥60-year-old females in post-ID fifth year period (p < 0.05, each). In another subgroup analysis based on the number of pre-ID CP visits, statistical significance was observed for pre-ID CP (0 time) in the third, fourth, and fifth year periods (p < 0.05, each). This study revealed that CRS participants were likely to receive CP diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine the natural course of pain after tonsillectomy.Methods: This study included 119 patients that underwent tonsillectomy between November 2013 and November 2015. After undergoing tonsillectomy, patients scored their pain using the visual analogue scale three times daily (morning, midday, and evening) for 2 weeks. A linear mixed model was used for statistical analyses.Results: Increasing postoperative days was negatively associated with pain following tonsillectomy surgery (estimated value [EV] of visual analogue score [VAS]/day=-0.42, 95% confidence interval [CI]=-0.43 to -0.41, P<0.001); the post-tonsillectomy pain curve illustrated this negative correlation. Postoperative pain was less in children and adolescents (≤18years old) than in adults (>18 years old) (EV=-0.81, 95% CI=-1.56 to -0.08, P=0.031). Mean tonsillectomy-associated pain on postoperative day 1 was 6.4 VAS. It decreased slightly to 5.3 VAS until postoperative day 7, after which it reduced sharply to 3.7 VAS within 3 days; on postoperative day 14 it had decreased to 1.6 VAS. Pain assessments were higher in the morning (EV=0.59, 95% CI=0.50 to 0.69, P<0.001) compared with assessments conducted in the evening.Conclusion: The natural course of postoperative tonsillectomy pain follows a gradual decline for 1 week after surgery, but decreases more rapidly after this period. [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]

Study Design: A retrospective study using the Korean Health Insurance Review and Assessment Service-National Sample Cohort was performed.Objective: To determine the rate and causes of mortality in vertebral fracture patients.Summary Of Background Data: Vertebral fractures are associated with increased mortality in prior studies.Methods: Of 1,125,691 patients, we collected data of 23,026 patients of all ages who experienced thoracic or lumber vertebral fractures between 2002 and 2013. The vertebral fracture participants were matched 1:4 with control participants, accounting for age, group, sex, income, and region of residence. Finally, 21,759 vertebral fracture participants and 87,036 control participants were analyzed. The index date was the date of diagnosis of vertebral fracture; participants from the control group were followed from the same index date as their matched counterparts. The follow-up duration was the index date to the death date or the last date of study (December 31, 2013). Patients were followed until death or censoring of the data. Death was ascertained in the same period, and causes of death were grouped into 12 classifications according to the Korean Standard Classification of Disease. A stratified Cox proportional hazards model was used.Results: The adjusted hazard ratio (HR) for mortality of vertebral fracture was 1.28 (P < 0.001) with the higher adjusted HR in younger patients. Mortalities caused by neoplasms; neurologic, circulatory, respiratory, digestive, and muscular diseases; and trauma were higher in the vertebral fracture group (P < 0.05), with muscular disease showing the highest odds ratio for mortality.Conclusion: Vertebral fractures were associated with increased mortality in Korean. Disease in muscuoskeletal system and connective tissue that possibly be associated with the fractures was most responsible for elevated death rates following vertebral fracture. Our findings may help caregivers provide more effective care, ultimately decreasing the mortality rate of vertebral fracture patients.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Background: Few studies have investigated the bidirectional association between psoriasis and depression. The aim of our study was to identify the association between psoriasis and depression.Methods: Data collected by the Korean Health Insurance Review and Assessment from 2002 to 2013 were used. In study I, psoriasis patients (n = 10,932) were matched 1:4 with control I group participants. In study II, depression patients (n = 60,383) were matched 1:4 with control II group participants. Matching was performed for age, sex, income, and region of residence. The stratified Cox-proportional hazard model was used to calculate the hazard ratio (HR) with crude and adjusted models.Results: In study I, the adjusted HR for depression was 1.13 (95% confidence interval (CI) = 1.03-1.24) in the psoriasis group compared to the control I group. In study II, the adjusted HR for depression was 1.11 (95% CI = 1.00-1.22) in the depression group compared to the control II group. In the subgroup analyses, the adjusted HRs for depression were 1.24 (95% CI = 1.00 - 1.53) in females aged < 40 years and 1.31 (95% CI = 1.04 - 1.66) in males aged ≥ 60 years. In the subgroup analyses from study II, the adjusted HRs for psoriasis were 1.56 (95% CI = 1.15 - 2.12) in males aged < 40 years and 1.35 (95% CI = 1.04 - 1.75) in males aged ≥ 60 years.Conclusions: We suggest that psoriasis and depression might have a bidirectional association. [ABSTRACT FROM AUTHOR]