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Objective: Chronic rhinosinusitis (CRS) is one of the most common chronic inflammatory diseases. The effect of chronic inflammation caused by CRS on the occurrence of various cancers has not been thoroughly evaluated. This study aimed to investigate the increased incidences of 10 types of cancers among CRS patients with/without nasal polyps (NP) using a national population-based database from the Korean Health Insurance Review and Assessment Service., Study Design: A case-control cohort study., Methods: We compared the prevalence of various comorbidities between CRS and control participants from a national cohort dataset of the Korean Health Insurance Review and Assessment Service., Methods: CRS participants (n = 6,919) and non-CRS (n = 27,676) participants were selected from among the 514,866 participants from 2002 to 2015. A stratified Cox proportional hazards model was utilized to assess the hazard ratio (HR) of CRS for 10 types of cancers., Results: A stratified Cox proportional hazard model demonstrated that the adjusted HR for hematologic malignancy was significantly higher in the CRS patients than in the controls regardless of the presence of NP (2.90 for total CRS; 2.15 for CRS with NP; 4.48 for CRS without NP). The HR for thyroid cancer was significantly higher in the CRS patients without NP but not in those with NP (1.50 for total CRS; 1.78 for CRS without NP)., Conclusion: This study showed that CRS participants had a significantly higher prevalence of hematologic malignancy and thyroid cancer., Level of Evidence: 4 Laryngoscope, 133:1044-1051, 2023., (© 2022 The American Laryngological, Rhinological and Otological Society, Inc.)

This study aimed to estimate the risk of mortality related to the number of missing teeth in a South Korean population. The ≥ 40-year-old population of the Korean National Health Insurance Service-Health Screening Cohort 2002-2003 was analyzed. Participants were selected from a total of 220,189 participants and included in groups of 0 teeth lost, 1-2 teeth lost, and ≥ 3 teeth lost. Among the total population, 17,211 participants were included in no missing teeth, 1-2 missing teeth, and ≥ 3 missing teeth and were randomly matched 1:1:1 for age and sex. Mortality from specific causes and all-cause mortality were compared among the groups. The hazard ratio (HR) of the number of missing teeth for all-cause mortality or each cause of mortality was analyzed using Cox proportional hazard models. According to the cause of death, the HRs for metabolic disease, digestive disease, and trauma were greater in the group with ≥ 3 missing teeth than in the no missing teeth group. The group with ≥ 3 missing teeth indicated a 1.19-fold higher HR for all-cause mortality than the no missing teeth group [95% confidence intervals (95% CIs) = 1.12-1.27, P < 0.001]. The group with 1- 2 missing teeth did not show a higher HR for all-cause mortality. In the group with 1-2 missing teeth, the HRs for mortality from mental disease and digestive disease were higher than those in the no missing teeth group. The group with 1-2 missing teeth did not show a higher HR for all-cause mortality. The number of missing teeth was linked with a higher risk of mortality. For specific causes of mortality, mortality from metabolic disease, digestive disease, and trauma was higher in the participants with the number of missing teeth., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kim, Lee, Yoo, Kwon, Kim, Kim, Byun, Park, Lee and Choi.)

Background: The purpose of this study was to evaluate body mass index (BMI) and systolic blood pressure (SBP)/diastolic blood pressure (DBP) between Korean adults who underwent thyroidectomy and comparison groups., Methods: Data were included from the Korean National Health Insurance Service-Health Screening Cohort (2002-2015). BMI and SBP/DBP were measured before thyroidectomy, 1 and 2 years after thyroidectomy ( n = 1995 in study I, n = 2162 in study II), comparing 1:4 matched participants ( n = 7980 in study I, n = 8648 in study II). The paired t-test and linear mixed model were used to identify the differences between groups., Results: DBP in both thyroid cancer II and comparison II group were significantly lower after thyroidectomy than before thyroidectomy. However, the interaction effect of thyroidectomy in study I and study II did not reach statistical significance., Conclusion: BMI, SBP and DBP were not significantly different between the thyroidectomy group and the matched comparison group.

Importance: A connection between Meniere disease (MD) and migraine has been proposed, but the temporal association remains unknown., Objective: To examine the bidirectional association of MD with migraine., Design, Setting, and Participants: This case-control study included participants 40 years or older from the Korean National Health Insurance Service Health Screening Cohort from 2002 to 2015., Main Outcomes and Measures: A total of 6919 patients with MD were matched with 27 676 control participants without MD for age, sex, income, region of residence, and index date. The incidence of migraine was analyzed in the MD and matched groups using a stratified Cox proportional hazard regression model. In addition, 35 889 patients with migraine were matched with 71 778 control participants without migraine. The incidence of MD was analyzed using a stratified Cox proportional hazard regression model., Results: Of 142 262 total participants, 94 611 (66.5%) were women. Migraine occurred in 695 of 6919 patients with MD (10.0%) and 970 of 27 676 matched control participants (3.5%). The MD group demonstrated a 2.22-fold higher risk of migraine than the matched control group (95% CI, 1.99-2.49). Meniere disease was present in 1098 of 35 889 patients with migraine (3.1%) and 781 of 71 778 matched control participants (1.1%). The migraine group had a 1.95-fold higher risk of MD than the matched control group (95% CI, 1.77-2.15)., Conclusions and Relevance: The results of this case-control study suggest that patients with MD had a greater risk of migraine occurrence. Furthermore, patients with migraine had a higher risk of MD. Based on the bidirectional association, therapeutics for migraine could potentially be applied to MD and vice versa.

The prevalence of neurodegenerative dementia is increasing owing to the rapid growth of the older population. We investigated risks and causes of mortality in Korean patients with neurodegenerative dementia using data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort with the aim to improve their care. From a pool of 1,125,691 patients, 11,215 patients aged ≥60 years who were diagnosed with dementia between 2002 and 2013 were examined along with 44,860 matched controls. A Cox proportional hazard model was used to calculate crude and adjusted hazard ratios (HRs). During the follow-up period, 34.5% and 18.8% of individuals in the neurodegenerative dementia and control groups, respectively, died ( P < 0.001). The adjusted HR for mortality in the neurodegenerative dementia group was 2.11 (2.41 and 1.96 in men and women, respectively). Moreover, the adjusted HRs in patients with neurodegenerative dementia were 3.25, 2.77, and 1.84 for those diagnosed at ages 60-69, 70-79, and ≥80 years, respectively. The highest odds ratio for mortality was noted among patients with neurologic disease (15.93) followed by those with mental disease (4.89). These data show that the risk of mortality increased regardless of age and sex in Korean patients with neurodegenerative dementia., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2022 Hyo Geun Choi et al.)

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

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., (© 2022. The Author(s).)

Background: The objective of this study was to investigate the risk of temporomandibular joint disorder (TMD) in patients with osteoporosis., Methods: Data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2015 were collected. Participants ≥ 40 years old were enrolled, and the history of osteoporosis was evaluated. The 62,328 osteoporosis patients were matched for age, sex, income, and region of residence with 62,328 control participants. The occurrence of TMD was assessed in both the osteoporosis and control groups during the follow-up period. Stratified Cox proportional hazard analyses for TMD were conducted for the osteoporosis and control groups. The hazard ratios (HRs) of osteoporosis for TMD were further analyzed by age and sex subgroups., Results: A total of 1.2% (725/61,320) of the osteoporosis patients and 0.6% (339/61,320) of the control participants had TMD (P<0.001). Osteoporosis was associated with an elevated HR of TMD (adjusted HR=1.96, 95% CI=1.72-2.23, P<0.001). Among the age and sex subgroups, the < 60-year-old mal\e group demonstrated an adjusted HR of osteoporosis for TMD as high as 4.47 (95% CI=1.17-17.12, P=0.029). Other age and sex subgroups also showed a higher HR for TMD associated with osteoporosis (adjusted HR=2.30, 95% CI=1.90-2.78, P<0.001 for the ≥ 60-year-old female group)., Conclusion: Osteoporosis was related to a higher risk of TMD in the adult population. A prominent association of osteoporosis with TMD was noted in middle-aged men and older women., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kim, Yoo, Kwon, Kim, Kim, Byun, Park, Lee and Choi.)

Importance: The COVID-19 pandemic has had a substantial psychological effect on young people. A quantitative assessment of the association between the pandemic and stress and suicidality in youths is needed., Objective: To investigate the association of the COVID-19 pandemic with self-reported stress and suicide-related behaviors in youths., Design, Setting, and Participants: This cross-sectional study used data from the the Korea Youth Risk Behavior Web-based Survey (KYRBWS) conducted in 2019 and 2020 with youths aged 12 to 18 years. Statistical analysis was performed from January to February 2021., Main Outcomes and Measures: The odds ratios (ORs) with 95% CIs for subjective stress level, sadness or despair, suicidal thoughts, suicide planning, and suicide attempts among 2020 participants were compared with those of the 2019 participants using multiple logistic regression analysis with complex sampling using weighted values., Results: The 48 443 youths in the 2019 KYRBWS (24 917 male youths [51.3%]; mean [SD] age, 15.0 [1.7] years) and the 44 216 youths in the 2020 KYRBWS (23 103 male youths [52.5%]; mean [SD] age, 15.1 [1.7] years) were compared. The degree of subjective stress was lower in the 2020 participants than in the 2019 participants (severe stress: adjusted OR [aOR], 0.90 [95% CI, 0.83-0.97]; very severe stress: aOR, 0.65 [95% CI, 0.60-0.72]). Sadness or despair was also lower in the 2020 participants than in the 2019 participants (aOR, 0.81 [95% CI, 0.78-0.84]). There were fewer suicide-related behaviors, including suicidal thoughts, suicide planning, and suicide attempts, among the 2020 participants than among the 2019 participants (suicidal thoughts: aOR, 0.77 [95% CI, 0.73-0.80]; suicide planning: aOR = 0.88 [95% CI, 0.81-0.96]; suicide attempts: aOR, 0.64 [95% CI, 0.58-0.70])., Conclusions and Relevance: This cross-sectional study found that severe stress, sadness or despair and suicide-related behaviors had inverse associations with the early COVID-19 pandemic in Korean youths. These findings suggest that levels of high stress decreased among Korean youths in the early period of the pandemic compared with prepandemic levels.

Objectives/hypothesis: This study investigated the impacts of air pollution and meteorological factors on the occurrence of epiglottitis., Study Design: A nested case-control study., Methods: Participants ≥40 years old in the Korean National Health Insurance Service-Health Screening Cohort were analyzed. A total of 2,615 epiglottitis patients and 10,460 matched control participants were analyzed. The odds ratios (ORs) for epiglottitis associated with meteorological and air pollution factors, including sulfur dioxide (SO 2 , ppb), nitrogen dioxide (NO 2 , ppb), ozone (O 3 , ppb), and carbon monoxide (CO, ppm), after 3, 7, 15, and 30 days of exposure were analyzed using conditional logistic regression adjusted for total cholesterol, blood pressure, fasting blood glucose, obesity, smoking, alcohol consumption, prior upper respiratory infection, tonsillectomy, immunocompromise, autoimmune disease, and the Charlson comorbidity index., Results: The daily temperature range and NO 2 exposure after 3 days were associated with increased rates of epiglottitis (OR = 1.03, 95% confidence interval [CI] = 1.02-1.05 for temperature range and OR = 1.78, 95% CI = 1.14-2.77 for NO 2 , respectively). These results were generally consistent at 7, 15, and 30 days., Conclusions: The temperature range and NO 2 exposure for 3, 7, 15, and 30 days were positively related to the occurrence of adult epiglottitis., Level of Evidence: 3 Laryngoscope, 131:2483-2489, 2021., (© 2021 The American Laryngological, Rhinological and Otological Society, Inc.)

The association between air pollutants and Meniere's disease has not been explored. The present study investigated the relationship between meteorological factors and air pollutants on Meniere's disease. Participants, aged ≥ 40 years, of the Korean National Health Insurance Service-Health Screening Cohort were included in this study. The 7725 patients with Meniere's disease were matched with 30,900 control participants. The moving average meteorological and air pollution data of the previous 7 days, 1 month, 3 months, and 6 months before the onset of Meniere's disease were compared between the Meniere's disease and control groups using conditional logistic regression analyses. Additional analyses were conducted according to age, sex, income, and residential area. Temperature range; ambient atmospheric pressure; sunshine duration; and levels of SO 2 , NO 2 , O 3 , CO, and PM 10 for 1 month and 6 months were associated with Meniere's disease. Adjusted ORs (odds ratios with 95% confidence interval [CI]) for 1 and 6 months of O 3 concentration were 1.29 (95% CI 1.23-1.35) and 1.31 (95% CI 1.22-1.42), respectively; that for the 1 and 6 months of CO concentration were 3.34 (95% CI 2.39-4.68) and 4.19 (95% CI 2.79-6.30), respectively. Subgroup analyses indicated a steady relationship of O 3 and CO concentrations with Meniere's disease. Meteorological factors and air pollutants were associated with the rate of Meniere's disease. In particular, CO and O 3 concentrations were positively related to the occurrence of Meniere's disease., (© 2021. The Author(s).)

Objectives: We evaluated changes in income levels in a hearing-impaired population., Methods: The study subjects were selected from the Korean National Health Insurance Service-Health Screening Cohort data from 2002 to 2015 of Koreans ≥40 years old. In total, 5,857 hearing-impaired subjects were matched with 23,428 comparison participants. Differences between the initial income level and income levels at 1, 2, 3, 4, and 5 years post-enrollment were compared between the hearing-impaired and comparison groups. The interaction of time and hearing impairment/comparison was estimated., Results: Both the hearing-impaired group and the comparison group showed increased income levels over time. In the hearing-impaired group, the income levels at 4 and 5 years post-enrollment were higher than the initial income level (each P<0.001). In the comparison group, the income levels of all the participants after 1-5 years were higher than the initial income level (each P<0.001). The interaction of time and hearing impairment was statistically significant (P=0.021)., Conclusion: The increase in income over time was relatively lower in the hearing-impaired adult population; therefore, the income gap widened between this population and the normal-hearing population.

The purpose of this study was to evaluate the association between female medical history and thyroid cancer. Methods: Data from the Korean Genome and Epidemiology Study were collected from 2004 to 2016. Among a total of 1303 participants with thyroid cancer and 106,602 control (non-thyroid cancer) participants, the odds ratios (ORs) with 95% confidence intervals (CIs) of hysterectomy, oophorectomy, use of oral contraceptives, and number of children were evaluated. Results: The adjusted OR of hysterectomy for thyroid cancer was 1.73 (95% CI = 1.48-2.01, p < 0.001) in the minimally adjusted model. The adjusted ORs for thyroid cancer were 1.89 (95% CI = 1.06-3.37, p = 0.031), 0.89 (95% CI = 0.83-0.94, p < 0.001), and 0.85 (95% CI = 0.73-0.99, p = 0.040) for bilateral oophorectomy, number of children, and use of oral contraceptives, respectively, in the fully adjusted model. In the subgroup analysis, the adjusted ORs of bilateral oophorectomy were significant in the younger age (OR = 3.62, 95% CI = 1.45-9.03, p = 0.006), while the number of children was significant in the older age (OR = 0.86, 95% CI = 0.80-0.93, p < 0.001). Conclusions: The ORs of hysterectomy and bilateral oophorectomy were significantly higher in the thyroid cancer group in the younger age group. The adjusted ORs of the number of children were significantly low in the older age group.

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

The association of thyroid cancer with statin use is controversial. This study aimed to investigate the association of previous statin use with thyroid cancer in the ≥ 40-year-old population in the Korean National Health Insurance Service-Health Screening Cohort. The 5501 patients in the thyroid cancer group were matched with the 22,004 patients in the non-thyroid cancer group for age, sex, income, and region of residence. Previous statin use during the 2 years before the diagnosis of thyroid cancer was examined. The odds ratios (ORs) with 95% confidence intervals (CIs) of previous statin use for thyroid cancer were estimated using conditional logistic regression analyses. Additionally, subgroup analyses were conducted. The thyroid cancer group showed more days of previous statin use than the non-thyroid cancer group (72.3, standard deviation [SD] = 181.2 days vs. 64.3, SD = 174.4 days, P = 0.003). Although the odds of previous statin use for thyroid cancer were high in the crude model (OR = 1.10, 95% CI 1.04-1.17, P = 0.002), they were low in the fully adjusted model (OR = 0.89, 95% CI 0.82-0.95, P = 0.001). According to age and sex subgroups, the younger (< 60 years old) male group showed lower odds for thyroid cancer according to previous statin use (adjusted OR = 0.70, 95% CI 0.55-0.88, P = 0.003), but this finding was not observed in other subgroups of older men or in any groups of women. Thyroid cancer was negatively associated with statin use in the previous 2 years in the adjusted model.

Telomerase reverse transcriptase gene promoter ( TERTp ) mutation is a potential candidate for pathogenesis and therapeutic target of tonsillar squamous cell carcinomas (TSCCs) in association with human papillomavirus (HPV). Their clinical relevance has not been validated under the new 8th American Joint Committee on Cancer (AJCC) staging system. We analyzed real-time peptide nucleic acid-mediated PCR and sequencing methods ( TERTp mutation) and real-time PCR-based assay (HPV) in 80 surgically resected TSCCs. The 8th edition staging system improved the stratification of the early and advanced stages and between T or N categories for overall survival over the 7th edition. TERTp mutation was found in 7.5%, and HPV in 80.0% of the patients. The majority (83.3%) of TERTp mutation cases were HPV-positive TSCCs. Applying the 8th edition staging system, TERTp mutation was an independent factor of poor prognosis for disease-free survival (DFS) in TSCC patients, supporting the clinical significance of TERTp mutation in tonsil cancer. TERTp mutations were also negatively correlated with overall survival and DFS in HPV-negative TSCCs. Conclusively, TERTp mutation provides negative prognostic impact on survival of surgically managed tonsil cancers staged with the AJCC 8th edition., Competing Interests: Conflict of InterestThe authors declare that they have no conflict of interest., (© The Author(s) 2020.)

Objective: To investigate the association between Bell's palsy and stroke according to the different types of stroke, using a sample cohort based on the national Korean population., Methods: Individuals aged ≥ 20 years were collected from the Korean National Health Insurance Service National Sample Cohort between 2002 and 2013. We extracted the data for Bell's palsy patients (n = 3658) and 1:4 matched controls (n = 14,632) and analyzed the occurrence of hemorrhagic or ischemic stroke in both groups. Matching was performed on the basis of age, gender, income, and region of residence. For Bell's palsy, we included only participants who received the diagnosis (ICD-10 code, G510) 2 or more times via ambulatory visits for the same episode with steroid treatment. Patient admission histories were used to identify occurrences of hemorrhagic stroke (I60, I61 and I62) and ischemic stroke (I63). Adjusted hazard ratios were calculated using stratified Cox proportional hazard models for the Charlson comorbidity index and 95% confidence intervals (CIs). For the subgroup analyses, we divided the participants by age, sex, and each time period after the onset of Bell's palsy (≤1 year, 1 to 2 years, 2 to 3years, > 3years)., Results: The risk of ischemic stroke was significantly increased in Bell's palsy patients compared to that in the controls (adjusted HR = 1.74, 95% CI = 1.38-2.19, P < 0.001). In the subgroup analyses, a significant association between two clinical disorders was observed in patients aged ≥ 50 years old, regardless of gender. The risk of ischemic stroke was significantly increased, especially within 2 years after Bell's palsy. In contrast, the risk of hemorrhagic stroke was not significantly increased., Conclusion: There is an association of Bell's palsy with ischemic stroke but not with hemorrhagic stroke., Competing Interests: Declaration of Competing Interest There are no competing interests for any author., (Copyright © 2020. Published by Elsevier B.V.)

Several previous studies have suggested a relationship between GERD and RA. However, no study has investigated the bidirectional relationship between GERD and RA. This study aimed to evaluate the causal relationships between rheumatoid arthritis (RA) and gastroesophageal reflux disease (GERD). Participants aged ≥ 20 years old in the Korean Health Insurance Review and Assessment Service-National Sample Cohort from 2002 to 2013 were enrolled. In study I, 132,140 GERD participants were 1:2 matched with 264,280 control I participants. In study II, 6615 RA participants were 1:4 matched with 26,460 control II participants. Both control I and control II groups were matched with their study groups for age, sex, income, and region of residence. The occurrence of RA (study I) and GERD (study II) were followed up in both the study and control groups. The hazard ratios (HRs) of GERD for RA (study I) and of RA for GERD (study II) were analysed using stratified Cox-proportional hazards models. In study I, 0.8% (1,034/132,140) of the GERD group and 0.5% (1,290/264,280) of the control I group had RA (P < 0.001). The GERD group demonstrated a 1.49-fold higher adjusted HR than did the control I group (95% confidence interval (95% CI) = 1.37-1.62, P < 0.001). In study II, 22.5% (1,490/6,615) of the RA group and 15.2% (4,034/26,460) of the control II group had GERD (P < 0.001). The RA group showed a 1.46-fold higher adjusted HR than did the control II group (95% CI = 1.38-1.55, P < 0.001). GERD and RA have bidirectional associations in Korean adult population. Key Points • Several previous studies have suggested a relationship between gastroesophageal reflux disease (GERD) and rheumatoid arthritis (RA). • However, no study has investigated the bidirectional relationship between GERD and RA. • This is the first study to present a bidirectional relationship between GERD and RA. • GERD and RA have bidirectional relations with each other.

Background: Epidemiological studies on the association between asthma and cardiovascular disease have reported conflicting results. This cross-sectional study evaluated the association between asthma and ischaemic heart disease (IHD)/stroke in Korean adults., Materials and Methods: Data from the Korean Genome and Epidemiology Study-Health Examinees were used. Among 173 209 participants, 3162 asthmatic and 159 408 control participants were selected. Histories of asthma, IHD and stroke were obtained. Participants were categorized according to their current status of asthma management: 'well-controlled', 'being treated', and 'not being treated'. Crude and adjusted (age, gender, body mass index, income, smoking, alcohol consumption, hypertension, diabetes, dyslipidaemia and nutritional intake) odds ratios (ORs) for IHD and stroke in asthmatic patients were analysed using a multiple logistic regression model., Results: Participants with asthma reported a significantly higher prevalence of IHD (6.0% vs 3.0%) and stroke (2.3% vs 1.4%) than those without asthma (P < .001). Asthmatic participants had a higher OR (1.46, 95% confidence interval [CI] = 1.251-1.71, P < .001) for IHD than those without asthma. The association between asthma and IHD was significant only in patients aged ≥53 years (men: adjusted OR = 1.31, 95% CI = 1.01-1.70, P = .046; women: adjusted OR = 1.64, 95% CI = 1.32-2.03, P < .001) according to age and sex and in the 'not being treated' asthma group (adjusted OR = 1.47, 95% CI = 1.14-1.91, P = .003) according to the asthma management status. Stroke was not significantly associated with asthma (adjusted OR = 1.17, 95% CI = 0.92-1.48, P = .203) in the adjusted model and all subgroup analyses., Conclusion: Asthma was associated with IHD, mainly in older patients and untreated asthma patients, but not with stroke., (© 2020 Stichting European Society for Clinical Investigation Journal Foundation. Published by John Wiley & Sons Ltd.)

This study aimed to evaluate the changes in weight and blood pressure in Korean adults who underwent tonsillectomy compared to controls. A nested case-control study used data from the Korean National Health Insurance Service-Health Screening Cohort (2002-2015). Tonsillectomy was defined using claim code Q2300. The changes in weight and systolic/diastolic blood pressure (SBP/DBP) were measured before tonsillectomy and 1 year after tonsillectomy (study I) in some participants and during the second year after tonsillectomy (study II) in other participants. Patients who underwent tonsillectomy ( n = 569 in study I; n = 556 in study II) were 1:4 matched with control participants ( n = 2276 in study I; n = 2224 in study II). The paired t -test and linear mixed model were used to test the differences between groups at each time point. There were no changes in body mass index ( p = 0.732 in study I; p = 0.128 in study II), SBP ( p = 0.344 in study I; p = 0.559 in study II), or DBP ( p = 0.826 in study I; p = 0.524 in study II) between the tonsillectomy patients and controls in the first or second year postoperatively. Subgroup analyses by age, sex, and degree of obesity showed consistent results. Tonsillectomy does not lead to a change in weight or blood pressure in Korean adults.

Objectives: Few studies have reported that mood disorders increase the risk of benign paroxysmal positional vertigo (BPPV). The purpose of our study was to demonstrate whether the incidence of BPPV in those with mood disorders differs from that in a matched control group., Study Design: Nationwide cohort observational study., Methods: Korean Health Insurance Review and Assessment Service-National Patient Samples were collected from 2002 to 2013. A 1:4 matched mood disorder group (n = 59,340) and control group (n = 237,720) were selected. The crude and adjusted (cerebral stroke, ischemic heart disease, anxiety disorder, and osteoporosis histories) hazard ratios (HRs) for depression and BPPV were analyzed using a stratified Cox proportional hazard model. The results were stratified by age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia in these analyses., Results: The incidence of BPPV was significantly higher in the mood disorder group than in the control group (3.2% vs. 2.1%, P < .001). Mood disorder increased the risk of BPPV (adjusted HR = 1.31, 95% confidence interval [CI] = 1.23-1.39, P < .001). In subgroup analyses, the incidence of BPPV in all age groups and in both sexes was significantly higher in the mood disorder group than in the control group., Conclusion: This population-based cohort study demonstrates that mood disorder was significantly associated with BPPV., Level of Evidence: N/A. Laryngoscope, 131:380-385, 2021., (© 2020 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The purpose of this study was to evaluate the long-term mortality and cause of death in patients with tracheostomy., Methods: Data from the Korean National Health Insurance Service-Health Screening Cohort were collected from 2002 to 2013. A total of 2394 tracheostomy participants and 9536 control participants were included in this study. The crude and adjusted hazard ratios (HRs) for tracheostomy-associated mortality were analyzed. Subgroup analysis according to age and cause of death was analyzed., Results: The tracheostomy group showed a significantly higher rate of death (69.1%) than the nontracheostomy group (13.3%). The adjusted HR for mortality was 13.5 in the tracheostomy group. The most common cause of death after tracheostomy was a circulatory disease, followed by neoplasm, respiratory disease, and trauma., Conclusions: Patients with tracheostomy had a significantly increased long-term mortality rate compared with patients with nontracheostomy. The circulatory disease was the most common cause of death following tracheostomy., (© 2020 Wiley Periodicals LLC.)

This study aims to assess the relationship between chronic rhinosinusitis (CRS) and dyslipidemia in a Korean population. The population aged 40 years or over was selected from the Korean National Health Insurance Service-National Health Screening Cohort. CRS was defined if patients were treated ≥2 times with ICD-10 code (J32) and underwent head and neck computed tomography. Patients with CRS were classified as having nasal polyps (J33) or not. Dyslipidemia was defined if participants with the ICD-10 code (E78) were treated ≥2 times from 2002 to 2015. A total of 6163 patients with CRS were matched with 24,652 controls (1:4 ratio) for sex, age, income, and residence. The adjusted odds ratios (aORs) of a previous dyslipidemia in patients with CRS were analyzed by conditional logistic regression analysis, adjusted for confounding factors. The prevalence of dyslipidemia was significantly higher in participants with CRS (26.1%) than in the controls (20.6%) ( p < 0.001). There was a significant positive association between CRS with/without nasal polyps and dyslipidemia (aOR = 1.36, 95%CI = 1.26-1.47, p < 0.001). The association between CRS and dyslipidemia was stronger for CRS without nasal polyps (aOR = 1.42, 95% CI = 1.28-1.57, p < 0.001) than for CRS with nasal polyps (aOR = 1.31, 95% CI = 1.17-1.47, p < 0.001). All age and sex subgroups exhibited consistent results. A personal history of dyslipidemia was associated with risk of CRS regardless of total cholesterol and the use of statins.

Psoriasis is a well-known immune-mediated disease. Its autoimmune pathophysiology is consistent with the immune-mediated systemic vascular hypothesis regarding the pathogenesis of sudden sensorineural hearing loss (SSNHL). The purpose of our study was to investigate whether psoriasis affects the prevalence of SSNHL in all age groups matched by age, sex, income, and region of residence. Korean Health Insurance Review and Assessment Service-National Patient Samples were collected from 2002 to 2013. A 1:4 matched psoriasis group (n = 12,864) and control group (n = 51,456) were selected. The crude (simple) and adjusted (Charlson comorbidity index) hazard ratios (HR) for psoriasis and SSNHL were analyzed using the stratified Cox proportional hazard model. The incidence of SSNHL was significantly higher in the psoriasis group than in the control group (0.5% vs. 0.4%, p = 0.004). Psoriasis increased the risk of SSNHL (adjusted HR = 1.44, 95% confidence interval (CI) = 1.09-1.90, p = 0.010). In the stratification analysis, the incidence of SSNHL was significantly higher in the 30-59-year-old group than other group SSNHL (adjusted HR = 1.50, 95% CI = 1.06-2.12, p = 0.023). In addition, SSNHL occurred significantly more frequently in men with psoriasis (adjusted HR = 1.70, 95% CI = 1.17-2.49, p = 0.006). Psoriasis increased the risk of SSNHL, and SSNHL was more prevalent in between the age of 30-59-year-olds and men with psoriasis.

Oral health can affect or be a manifestation of general health. Although oral health assessment has been used as a proxy for general health, few studies have reported an association between oral health status and allergic diseases. This cross-sectional study aimed to investigate the relationship between subjective oral health status and asthma/allergic rhinitis in a nationwide representative sample of Korean adults.A total of 227,977 participants from the Korean Community Health Survey 2015 were enrolled. Participants were asked about their subjective oral health status (very good, good, normal, poor, very poor), periodontal status (mobility, swelling, calculus, bleeding), teeth brushing frequency, and scaling history within the past 12 months. Histories of physician-diagnosed asthma and allergic rhinitis throughout life were surveyed. The associations between subjective oral health status and allergic diseases were analyzed using multiple logistic regression analysis. Age, sex, economic level, educational level, region of residence, smoking, alcohol, obesity, subjective general health status, stress level, physical activity, periodontal status, teeth brushing frequency, and scaling history within the past 12 months were adjusted as covariates.A higher prevalence of asthma (3.6%) was reported in the poor oral health group than in the good (1.8%) and normal (2.1%) groups (P < .001). Poor oral health status was significantly related to asthma, with an adjusted odds ratio (aOR) of 1.19 (95% CI = 1.07-1.33, P = .002). Although the prevalence of allergic rhinitis was not higher in the poor oral health group (13.4%) than in the good (15.4%) and normal oral health groups (15.9%), the aOR for allergic rhinitis was 1.05 (95% CI = 1.00-1.11, P = .045) in the poor oral health group after adjusting for covariates.Subjective poor oral health status was significantly associated with asthma and allergic rhinitis in Korean adults.

This study aimed to evaluate the association between asthma and the intake of coffee/green tea/soda. We used Health Examinee data from the Korean Genome and Epidemiology Study (2004-2016). The participants ( n = 3146 with asthma; n = 158,902 non-asthma) were asked about the frequency and amount of their coffee/green tea/soda intake. Multiple logistic regression analyses were used to calculate the adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for asthma according to the frequency and amount of coffee/green tea/soda intake. Compared to the group consuming no coffee, the aORs for asthma were 0.82 (95% CI = 0.73-0.93, p = 0.002) in the group consuming coffee 1-2 times/day and 0.87 (95% CI = 0.78-0.97, p = 0.011) in the group consuming coffee in quantities of 1 cup, respectively. However, the frequency and amount of green tea and soda consumption were not significantly associated with asthma after adjusting for coffee consumption (all p > 0.05). These findings were consistent in the female subgroup (1-2 times/day: aOR = 0.76, 95% CI = 0.66-0.87, p < 0.001, and 1 cup each time: aOR = 0.79, 95% CI = 0.70-0.90, p < 0.001) but not in the male subgroup. Drinking 1 cup of coffee each time and 1-2 times per day may have protective effects against asthma in a Korean population. However, the associations between asthma and green tea/soda cannot be clearly established.

Background: A few studies have reported the association between asthma and osteoporosis. We aimed to analyze the association of asthma and its subgroups with osteoporosis in the Korean adult population., Methods: We used the health examinee (HEXA) data from the Korean Genome and Epidemiology Study (KoGES) obtained between 2004 and 2016. We included 162,579 participants (n = 3,160 with asthma; n = 159,419 controls) who reported their previous histories of asthma and osteoporosis. The participants were categorized into 3 groups based on asthma management: participants who did not need further treatment due to controlled symptoms (well controlled); participants with ongoing treatment (being treated); participants who were not treated even though they had symptoms (not being treated). Multiple logistic regression analyses were used to calculate the adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for osteoporosis. Subgroup analyses for age and sex were conducted., Results: The prevalence of osteoporosis was higher in patients with asthma (13.6%) than in controls (6.8%). In the full-adjusted model, the aORs for osteoporosis were 1.74 (95% CI 1.55-1.94, P < 0.001) in patients with asthma compared to controls. There were consistent findings across the age and sex subgroups. The aORs for osteoporosis were 1.43 (95% CI 1.10-1.86, P = 0.008) in the well-controlled asthma group; 1.55 (95% CI 1.28-1.89, P < 0.001) in the being treated asthma group; and 1.96 (95% CI 1.66-2.31, P < 0.001) in the not being treated asthma group compared to the control group., Conclusion: Asthma was associated with osteoporosis in the Korean adult population. Patients with asthma not being treated showed the highest ORs for osteoporosis., Competing Interests: Competing interestsThe authors declare no conflict of interest., (© The Author(s) 2020.)

Background: Recent studies have proposed that handwashing can lead to the development of allergic disease by reducing skin epithelial barrier integrity. The purpose of this study was to evaluate the association between personal hygiene practices and allergic rhinitis (AR) in a nationally representative sample of Korean adolescents., Methods: A total of 62,276 adolescent participants (aged 12 to 18 years) were analyzed using the Korea Youth Risk Behavior Web-based Survey, which was conducted in 2017. Participants were asked about the frequency of handwashing considering 5 situations. AR histories throughout life and in the last 12 months were obtained. The associations between AR and hygiene scores were analyzed using multiple logistic regression, with adjustment for possible confounders. Subgroup analyses were conducted for school level, age, economic level, and education level of each parent., Results: The analysis of the general characteristics showed that younger age, increased number of days of physical activity, male sex, living in a large city, high economic level, high education levels of father and mother, nonsmoking status, and no alcohol consumption were associated with a relatively high hygiene score (p < 0.001). The adjusted odds ratio (aOR) of AR was 1.12 (95% confidence interval [CI], 1.06 to 1.18; p < 0.001) throughout life and 1.21 (95% CI, 1.14 to 1.29; p < 0.001) for the previous 12 months in the highest compared with the lowest hygiene score groups. Consistent results were obtained in the female sex, any school level, middle economic level, and both parents with any education level., Conclusion: The association between high hygiene scores and AR was significant in Korean adolescents after adjustment for several variables., (© 2020 ARS-AAOA, LLC.)

Background: Hepatitis B virus (HBV) and hepatitis C virus (HCV) are suspected of being associated with non-Hodgkin lymphoma (NHL); however, persuasive data are lacking. Hence, a nested large-population case-control study was performed to investigate such associations in Koreans., Methods: Data were collected from 929 patients with NHL and 3716 healthy subjects, who were matched 1:4 for age, sex, income, and region of residence, from the Korean Health Insurance Review and Assessment Service-National Sample Cohort. The diagnoses of NHL and HBV/HCV infection were based on the International Classification of Diseases (version 10) codes. Conditional logistic regression models were used to assess odds ratios (ORs) for NHL with respect to HBV or HCV with adjustment for the Charlson comorbidity index., Results: HBV and HCV rates were higher in the NHL group (3.3% and 1.3%, respectively) than in the control group (0.9% and 0.3%, respectively; P < .001 for each). The adjusted OR of hepatitis infection in patients with NHL were 3.25 (95% confidence interval [CI] = 1.99-5.31) for HBV and 3.36 (95% CI = 1.51-7.46) for HCV (P < .001 for each). Subgroups categorized by age (<55 vs ≥55 years) or sex showed significantly higher adjusted ORs of HBV for NHL. Moreover, patients with NHL ≥ 55 years of age or those who were female showed significantly higher adjusted ORs of HCV; those <55 years or who were male also tended to have higher ORs of HCV., Conclusion: Infection with either HBV or HCV is associated with NHL in Koreans., (© 2019 Wiley Periodicals, Inc.)

Background: The causal relationship between asthma and gastroesophageal reflux disease (GERD) is unknown in children., Methods: The Korean Health Insurance Review and Assessment Service-National Sample Cohort 2002-2013 was used. The population age <15 years was selected. In study I, 86,096 asthmatic children were 1:1 matched with 86,096 control I participants. In study II, 532 GERD children were 1:2 matched with 1064 control II participants. The stratified Cox proportional hazard ratios for GERD in patients with asthma (study I) and asthma in patients with GERD (study II) were analyzed., Results: In total, 0.7% (583/86,096) of the asthma group and 0.5% (430/86,096) of the control I group had GERD (P < 0.001). The asthma group demonstrated a 1.36 times higher HR for GERD than the control I group (95% CI = 1.20-1.54, P < 0.001). Subgroup analyses according to age and sex showed consistent results. In total, 15.0% (80/532) of the GERD group and 10.0% (106/1,064) of the control II group had asthma (P < 0.001). The GERD group showed a 1.62-fold higher HR for asthma than the control II group (95% CI = 1.21-2.18, P < 0.001)., Conclusion: GERD and asthma demonstrated a bidirectional relationship in children.

The purpose of this study was to evaluate the association between oral health and asthma/allergic rhinitis/atopic dermatitis in a large representative Korean adolescent population.A total of 136,027 participants (aged 12-18 years old) were selected from the Korea Youth Risk Behavior Web-based Survey 2014 to 2015. The subjects' history of asthma, allergic rhinitis, and atopic dermatitis was determined by inquiring whether they had been diagnosed by a medical doctor within the previous 12 months or throughout life. Participants were asked if they had experienced the following 6 symptoms regarding oral health in the past 12 months: "chipped or broken tooth," "toothache when eating or drinking," "throbbing and sore tooth," "sore and bleeding gums," "pain in the tongue or inside the cheeks," and "unpleasant breath." The participants were divided into 3 groups according to the number of oral health-related symptoms as follows: good oral health (symptoms = 0), moderate oral health (symptoms = 1), and poor oral health (symptoms = 2-6). Multiple logistic regression analyses calculated the adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for asthma/allergic rhinitis/atopic dermatitis within the past 12 months and throughout life among groups with oral health-related symptom groups.Older age, female sex, fewer days of physical activity, lower parental economic level, lower parental education level, smoking, and frequent alcohol consumption were associated with poor oral health (each P < .001). The aORs for asthma/allergic rhinitis/atopic dermatitis were 1.48 (95% CI = 1.34-1.63, P < .001), 1.42 (95% CI = 1.36-1.47, P < .001), and 1.35 (95% CI = 1.28-1.43, P < .001), respectively, in the poor oral health group compared to the good oral health group.Poor oral health was significantly correlated with the prevalence of asthma/allergic rhinitis/atopic dermatitis within the past 12 months and throughout life in Korean adolescents. Based on our comparative data, oral health-related education may be considered to adolescents with allergic disease for good oral health.

The aim of this study was to evaluate an epidemiologic association of asthma and chronic rhinosinusitis (CRS) using a national sample cohort of the Korean population. We collected data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort between 2002 and 2013, and two different case-control cohorts were designed (1st: asthmatic patients matched in a 1:1 ratio with 204,119 non-asthmatics as control I, 2nd: CRS patients matched in a 1:4 ratio with 124,020 non-CRS patients as control II). Bidirectional association was examined using Cox proportional hazard models stratified by age, sex, income, and region of residence. Patients with asthma had an increased risk of developing CRS [adjusted hazard ratio (95% confidence interval) = 1.74 (1.67-1.80)], both with nasal polyps [1.55 (1.36-1.78)], without nasal polyps [1.74 (1.67-1.81)]. In the second cohort, patients with CRS had increased risk of developing asthma [1.85 (1.80-1.91)] with similar results for those with and without nasal polyps. The strongest association for risk of CRS was in 20-39 years old men with asthma [2.41 (1.97-2.96)], while the strongest association for increased risk of asthma in those with CRS group was also seen in this same subgroup [2.40 (2.18-2.63)]. CRS and asthma had a bidirectional influence on each other. CRS increased the risk of asthma, and asthma increased the risk of CRS, especially in young men.

To evaluate the association between appendectomy and the occurrence of gallstones using a national sample cohort from Korea.The Korean National Health Insurance Service-National Sample Cohort was collected from 2002 to 2013. We extracted data for patients who had undergone appendectomy (n = 14,955) and a 1:4 matched control group (n = 59,820) and then analyzed the occurrence of gallstones. The patients were matched according to age, sex, income, region of residence, hypertension, diabetes mellitus, and history of dyslipidemia. Appendectomies were identified using operation codes (Q2860-Q2863) for appendicitis alone (International Classification of Disease-10: K35). Gallstones were diagnosed if the corresponding International Classification of Disease-10 code (K80) was reported ≥2 times. Crude (simple) and adjusted hazard ratios (HRs) were analyzed using stratified Cox proportional hazard models, and 95% confidence intervals were calculated. Subgroup analyses were performed based on age, sex, and time period after appendectomy.The adjusted HR for gallstones was 1.78 (95% confidence interval = 1.51-2.09, P < .001) in the appendectomy group. Consistent HRs were found in the analyses of all the subgroups determined using age and sex, with the exception of men ≥60 years of age. The risk of gallstones was increased during the first year after appendectomy.The occurrence of gallstones was increased in the patients who had undergone appendectomy.

This study investigated the relationship of weather and air pollution with the onset of Bell's palsy. The Korean Health Insurance Review and Assessment Service-National Sample Cohort (HIRA-NSC) data from 2002 through 2013 were used. The 3,935 Bell's palsy patients were matched with 15,740 control participants. The meteorological data, including daily mean temperature (°C), daily mean highest temperature (°C), daily mean lowest temperature (°C), daily mean temperature difference (°C), relative humidity (%), spot atmospheric pressure (hPa), sulfur dioxide (SO 2 ) (ppm), nitrogen dioxide (NO 2 ) (ppm), ozone (O 3 ) (ppm), carbon monoxide (CO) (ppm), and PM 10 (particulate matter ≤ 10 μg/m 3 ) for 60 days, 30 days, 14 days, 7 days, and 3 days prior to the index date were analyzed for Bell's palsy cases and controls. Conditional logistic regression analysis was used to estimate the odds ratios (ORs) of the association between the meteorological data and Bell's palsy. The mean NO 2 and PM 10 concentrations for 60 days were higher, while that of O 3 was lower in the Bell's palsy group than in the control group (both P < 0.001). The Bell's palsy group showed 16.63-fold higher odds of NO 2 for 60 days (0.1 ppm) than the control group (95% CI = 10.18-27.16, P < 0.001). The ORs of PM 10 , and O 3 for 60 days showed inconsistent results according to the included variables. Bell's palsy was related to high concentrations of NO 2 .

The aim of this study was to investigate the association of body mass index (BMI), alcohol consumption, and smoking status with the occurrence of Bell's palsy. The Korean National Health Insurance Service-Health Screening Cohort of a ≥ 40-year-old population from 2000-2003 was used. A total of 5,632 Bell's palsy participants were matched with 22,528 control participants in terms of age, sex, income, region of residence, and past medical histories of hypertension, diabetes, and dyslipidemia. Bell's palsy was classified by a history of ≥2 diagnoses with ICD-10 code (G510) and steroid treatment. BMI (kg/m 2 ) was classified as <18.5 (underweight), ≥18.5 to <23 (normal), ≥23 to <25 (overweight), ≥25 to <30 (obese I), and ≥30 (obese II). Alcohol consumption was divided into non-drinkers and those who drank 2-3 times a month, 1-2 times a week, and ≥3 times a week. Smoking status was categorized as current smokers, past smokers, and non-smokers. The odds of obesity, alcohol consumption, and smoking with Bell's palsy were analyzed using logistic regression analysis. BMI showed proportionally positive associations with Bell's palsy (adjusted OR [95% CI] = 0.61 [0.47-0.79] for underweight, 1.16 [1.08-1.26] for normal, 1.24 [1.15-1.33] for obese I, and 1.61 [1.38-1.88] for obese II, P < 0.001). The odds of alcohol consumption with Bell's palsy were 0.90 (95% confidence interval [CI] = 0.82-0.99) for 2-3 times a month, 0.77 (95% CI = 0.69-0.85) for 1-2 times a week, and 0.79 (95% CI = 0.71-0.88) for ≥3 times a week compared to nondrinkers (P < 0.001). Smoking did not show a relationship with the occurrence of Bell's palsy. Obesity was related to the risk of Bell's palsy in the population over 40 years old. On the other hand, alcohol consumption was negatively associated with the occurrence of Bell's palsy.

This study aimed to evaluate the risk of dementia after distal radius, hip, and spine fractures.Data from the Korean National Health Insurance Service-National Sample Cohort were collected for the population ≥ 60 years of age from 2002 to 2013. A total of 10,387 individuals with dementia were matched for age, sex, income, region of residence, and history of hypertension, diabetes, and dyslipidemia with 41,548 individuals comprising the control group. Previous histories of distal radius, hip, and spine fractures were evaluated in both the dementia and control groups. Using ICD-10 codes, dementia (G30 and F00) and distal radius (S525), hip (S720, S721, and S722), and spine (S220 and S320) fractures were investigated. The crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of dementia in distal radius, hip, and spine fracture patients were analyzed using conditional logistic regression analyses. Subgroup analyses were conducted according to age, sex and region of residence.The adjusted ORs for dementia were higher in the distal radius, hip, and spine fracture group than in the non-fracture group (adjusted OR = 1.23, 95% CI = 1.10 -1.37, P < .001 for distal radius fracture; adjusted OR = 1.64, 95% CI = 1.48 - 1.83, P < .001 for hip fracture; adjusted OR = 1.31, 95% CI = 1.22 - 1.41, P < .001 for spine fracture). The results in subgroup analyses according to age, sex and region of residence were consistent.Distal radius, hip, and spine fractures increase the risk of dementia.

This study aimed to evaluate the relationship between Bell's palsy and rheumatoid arthritis in a national sample cohort from Korea.Data were collected for individuals ≥20 years old from 2002 to 2013 in the Korean National Health Insurance Service-National Sample Cohort. We extracted data for patients with rheumatoid arthritis (n = 7628) and 1:4-matched controls (n = 30,512) and analyzed the occurrence of Bell's palsy in both groups. Matching was performed based on age, sex, income, and region of residence. Rheumatoid arthritis was diagnosed according to International Classification of Disease-10 (ICD-10) codes (M05-M06) and the prescription of biological agents and/or disease-modifying antirheumatic drugs. Bell's palsy patients were diagnosed according to ICD-10 code H912 and treatment ≥2 times with steroids. Adjusted hazard ratios (HRs) were calculated using stratified Cox proportional hazard models for the Charlson comorbidity index and 95% confidence intervals (CIs). Subgroup analyses based on age and sex were also performed.The rates of Bell's palsy were similar between the rheumatoid arthritis group (0.5% [38/7628]) and the control group, with no significant difference (0.4% [124/30,512], P = .270). The adjusted HR for Bell's palsy was 1.12 (95% CI, 0.78-1.62) in the rheumatoid arthritis group (P = .540). In the subgroup analyses according to age and sex, the relationship between Bell's palsy and rheumatoid arthritis did not reach statistical significance.The risk of Bell's palsy was not increased in patients with rheumatoid arthritis.

The purpose of this study was to investigate the association of herpes zoster infection with peptic ulcer disease in a Korean population.The Korean National Health Insurance Service selects samples directly from the entire Korean population database, and 1,125,691 participants with 114,369,638 medical claim codes were selected from the entire Korean population (50 million). A total of 127,802 peptic ulcer disease participants were matched with 127,802 control participants at a ratio of 1:1, considering age group, sex, income group, region of residence, hypertension, diabetes, and dyslipidemia. We analyzed stratified Cox proportional hazard models to calculate the hazard ratios of peptic ulcer with respect to herpes zoster. For subgroup analyses, we divided the participants by age, sex, and time periods after the index date.The rate of herpes zoster was higher in the peptic ulcer group (9.1% [11,669/127,802]) than in the control group (7.4% [9,397/127,802], P < .001). The adjusted hazard ratio of herpes zoster was 1.24 (95% CI = 1.21-1.28, P < .001). In subgroup analyses performed according to age and sex, all crude and adjusted hazard ratios of herpes zoster were higher in the peptic ulcer disease group than in the control group (each P < .05). In another subgroup analysis according to follow-up periods, the crude and adjusted hazard ratios of herpes zoster were higher in the peptic ulcer disease group than in the control group except for < 1 year periods after the index dates (each P < .001).The hazard ratios of herpes zoster were significantly increased in the peptic ulcer group compared with those in the control group in all age and sex groups.

A few studies have explored the association between depression and sudden sensorineural hearing loss (SSNHL). This study was aimed to investigate the reciprocal relations between SSNHL and depression using a nationwide cohort of the Korean population. Subjects aged > 20 years from the Korean National Health Insurance Service-National Sample Cohort were enrolled from 2002 to 2013. In study I, a total of 60,178 depressed patients were matched 1:4 with 242,872 control I subjects. In study II, a total of 4,328 SSNHL patients were 1:4 matched with 17,312 control II subjects. They were matched for age, sex, income, and region of residence. The Charlson comorbidity index (CCI) was adjusted. Subgroup analysis was performed according to age and sex. The crude and adjusted CCI hazard ratios (HRs) of SSNHL in depressed patients (study I) and depression in SSNHL patients (study II) were analyzed using the stratified Cox proportional-hazard model. In study I, the depression group exhibited an elevated adjusted HR of SSNHL 1.16 times that of the control group (confidence interval [95% CI] = 1.02-1.31, P < 0.023). The middle-aged women subgroup demonstrated an increased risk of SSNHL within the depression group. In study II, the SSNHL group showed a higher adjusted HR of depression 1.29 times that of control II group (95% CI = 1.06-1.57, P = 0.010). The middle-aged women subgroup showed an elevated risk of depression in the SSNHL group. The risk of SSNHL was elevated in the depressed patients and the risk of depression was increased in the SSNHL patients.

Objective: The purpose of the present study was to estimate the risk of mortality in hearing loss subjects in accordance with the cause of death., Study Design: A longitudinal follow up study., Setting: Data from the Korean National Health Insurance Service-National Sample Cohort were collected from a period between 2002 and 2013., Patients and Intervention: The 4,606 severe and 1,007 profound hearing loss participants with 40 or more years old were 1:4 matched with control participants, respectively, for age, sex, income, and region of residence. The causes of death were grouped into 12 classifications., Main Outcome Measures: The ratio of mortality was compared between the hearing loss and control group using a χ test or Fisher's exact test. In a Cox-proportional hazard model, age, sex, income, region of residence, and past medical histories were considered confounders., Results: The severe and profound hearing loss groups showed 4.07 (95% CI = 3.71-4.46, p < 0.001) and 4.22 times (95% CI = 3.52-5.05, p < 0.001) higher mortality ratios in the adjusted models, respectively. Both the severe and profound hearing loss groups showed higher mortality by infection, neoplasm, trauma, and metabolic, mental, circulatory, respiratory, and digestive diseases than control groups (p < 0.05). Among various causes of death, death by trauma revealed the highest odds ratios in both the severe and profound hearing loss groups., Conclusion: Hearing loss was associated with a significant increase in mortality.

Objective: To evaluate the risk of spine fracture in patients with mood disorder using a nationwide cohort., Design: A longitudinal follow-up study., Setting: Claims data for the population ≥20 years of age were collected from 2002 to 2013 for the Korean National Health Insurance Service-National Sample Cohort., Participants: A total of 60 140 individuals with mood disorder were matched with 240 560 individuals (control group) for age, sex, income, region of residence and osteoporosis., Interventions: In both the mood disorder and control groups, the history of spine fracture was evaluated. The International Classification of Diseases 10th Revision codes for mood disorder (F31-F39) and spine fracture (S220 and S320) were included., Primary and Secondary Outcome Measures: The univariable and multivariable HRs and 95% CIs of spine fracture for patients with mood disorder were analysed using a stratified Cox proportional hazards model. Subgroup analyses were conducted according to the history of osteoporosis, age and sex., Results: Approximately 3.3% (2011/60 140) of patients in the mood disorder group and 2.8% (6795/240 560) of individuals in the control group had spine fracture (p<0.001). The mood disorder group demonstrated a higher adjusted HR for spine fracture than the control group (multivariable HR=1.10, 95% CI 1.04 to 1.15, p<0.001). The participants without osteoporosis showed a higher HR of mood disorder for spine fracture than the control participants (multivariable HR=1.25, 95% CI 1.14 to 1.37, p<0.001). According to age and sex, this result was consistent in subgroups of women aged 20-39 and 40-59 years and men aged ≥60 years., Conclusion: The risk of spine fracture was increased in patients with mood disorder. The potential risk of spine fracture needs to be evaluated when managing patients with mood disorder., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The study aimed to expand previous data regarding an association between asthma and appendectomy in children compared with the population of all ages.The Korean Health Insurance Review and Assessment Service-National Sample Cohort from 2002 through 2013 was used. In all, 22,030 participants who underwent appendectomy were matched for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia with 88,120 participants who were included as a control group. In both the appendectomy and control groups, previous history of asthma was investigated. Appendectomy for appendicitis was identified based on a surgical code (International Classification of Disease-10 [ICD-10]: K35). Asthma was classified using an ICD-10 code (J45 and J46) and medication history. The crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of asthma for appendectomy were analyzed using conditional logistic regression analysis. Subgroup analyses were conducted according to age and sex.Approximately 15.2% (3358/22,030) of individuals in the appendectomy group and 13.3% (11,749/88,120) of those in the control group had asthma (P < .001). The appendectomy group demonstrated a higher adjusted odds of asthma than the control group (adjusted OR 1.18, 95% CI 1.13-1.23, P < .001). This result was consistent in the subgroups divided according to age and sex.The odds for asthma were higher in the appendectomy group than in the control group.

This study sought to evaluate associations between nephrolithiasis and hemorrhagic and ischemic stroke using a national sample cohort from Korea. Data from 2002 to 2013 were collected for individuals ≥ 20 years of age in the Korean National Health Insurance Service (NHIS)-National Sample Cohort. We extracted nephrolithiasis patients (n = 22,636) and 1:4 matched controls (n = 90,544) and analyzed the occurrence of stroke. Matching was performed based on age, sex, income, region of residence, hypertension, diabetes mellitus, and dyslipidemia history. Crude and adjusted hazard ratios (HRs) were calculated using Cox proportional hazard models, and 95% confidence intervals (CIs) were determined. We performed subgroup analyses according to age, sex, and follow-up period. The adjusted HR of ischemic stroke was 1.13 (95% CI = 1.06-1.21) in the nephrolithiasis group (P < 0.001). The relationship between nephrolithiasis and ischemic stroke remained present for the young women and middle-aged men as well as during a follow-up period of ≤ 1 year. The HR for hemorrhagic stroke did not reach statistical significance. The risk of ischemic stroke was higher in the nephrolithiasis patients., Competing Interests: Competing Interests: The authors do not have any financial or personal relationships with people or organizations that could inappropriately influence their work in the present article.

Objectives: The present study evaluated the associations between gastroesophageal reflux disease (GERD) and head and neck cancer using a national sample cohort of the Korean population., Design: We designed two studies using data collected from patients aged ≥40 years in the Korean National Health Insurance Service-National Sample Cohort from 2002 to 2013., Main Outcome Measures: Study I included participants with GERD matched 1:2 with controls and analysed the incidences of lip and oral cavity, oropharynx, hypopharynx and larynx cancers. Study II included participants with larynx cancer matched 1:4 with controls and analysed the previous histories of GERD. Head and neck cancer was identified using medical claim codes for surgical, radiation and chemotherapeutic treatments and death records from the National Statistical Office. Crude and adjusted hazard ratios (HRs) were analysed using the Cox proportional hazard model. Crude and adjusted odds ratios (ORs) were analysed using unconditional logistic regression analyses. Subgroup analyses were performed on groups stratified by age and sex., Results: The adjusted HR for larynx cancer was 2.32 (95% confidence interval (CI) = 1.53-3.52, P < 0.001) in the GERD group. However, the HRs for lip and oral cavity cancer, oropharynx cancer and hypopharynx cancer were not statistically significant (study I). The adjusted OR for GERD was 2.03 (95% CI = 1.40-2.96, P < 0.001) in the larynx cancer group; consistent results were obtained in subgroup analyses., Conclusion: Gastroesophageal reflux disease increases the risk of larynx cancer., (© 2019 John Wiley & Sons Ltd.)

Background: The purpose of this study was to evaluate the relations between gastroesophageal reflux disease (GERD) and chronic rhinosinusitus (CRS) in a Korean population., Methods: Subjects from the Korean National Health Insurance Service-National Sample Cohort, all ≥20 years old, were assessed from 2002 to 2013. In total, 23,489 CRS participants were matched with 93,956 controls at a ratio of 1:4 with respect to age, group, sex, income group, region of residence, hypertension, diabetes, and dyslipidemia. We analyzed previous history of GERD in the CRS and control groups. The CRS group included patients identified using International Classification of Diseases 10th edition (ICD-10) codes (J32) who had treated their CRS ≥2 times and had undergone head and neck computed tomography (CT). The GERD group included patients identified using the ICD-10 (K21) code who had treated their GERD ≥2 times and had taken a proton pump inhibitor (PPI) for ≥2 weeks. Crude and adjusted odds ratios (ORs) were analyzed using unconditional logistic regression analyses. The 95% confidence intervals (CIs) were calculated. Subgroup analyses were performed according to age and sex., Results: The rate of GERD was higher in the CRS group (17.1% [4020 of 23,489]) than in the control group (9.1% [8522 of 93,956]; p < 0.001). The adjusted OR of GERD was 2.04 (95% CI, 1.96-2.13; p < 0.001) in the CRS group. The results of the subgroup analyses were consistent., Conclusion: The ORs of GERD were increased in CRS participants. This relationship was consistent in all age and sex groups., (© 2018 ARS-AAOA, LLC.)

Objective: The present study compared the frequency of depressive disorder in patients with thyroid cancer who had undergone thyroidectomy with the frequency in control individuals., Study Design: Retrospective population-based cohort study., Setting: This study used data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort., Subject and Methods: A total of 3609 participants with thyroid cancer who had undergone thyroidectomy between 2003 and 2011 were enrolled in this study and matched 1:4 with 14,436 control participants by age, sex, income, and region of residence. The cumulative incidence of postoperative depressive disorder was evaluated over a period of 10 years after the thyroidectomies and compared with the incidence in controls. Depressive disorder was diagnosed by a psychiatrist., Results: The incidence of depressive disorder was significantly higher in the thyroid cancer with thyroidectomy group than in the controls up to postoperative year 1. A subgroup analysis showed the same higher incidence of depressive disorder in the thyroid cancer group than controls for up to 1 year after operations in young adult (≤44 years old), female, urban, and low-income groups. However, the incidence was elevated only in the year of the thyroidectomies themselves in middle-aged and older, rural, and high-income groups., Conclusion: Patients with thyroid cancer who undergo thyroidectomy have depressive disorder more frequently than normal controls. However, the frequency of depressive disorder after thyroidectomy recovers in a shorter period in middle-aged or older, high-income, and rural-dwelling patients, compared to younger, low-income, and urban-dwelling patients.

Programmed cell death-1 ligand-1 (PD-L1), essential for immune evasion, is a potential candidate for pathogenesis and therapeutic target of human papillomavirus (HPV)-positive tonsillar squamous cell carcinomas (TSCCs). MET/hepatocyte growth factor signaling and transcription factors involved in epithelial-to-mesenchymal transition (EMT) upregulate PD-L1, which can contribute to clinical outcome. Intratumoral heterogeneity of PD-L1 expression is of clinical importance in selection bias due to false-negative patient enrollment. However, the clinicopathological features, prognostic value, and coexpressed molecules of PD-L1 remain unclear in TSCCs. PD-L1 expression was evaluated via immunohistochemistry using a specific monoclonal antibody (SP142) between whole-tissue and tissue microarray (TMA) sections of 79 tumors (5% cutoff value with weak staining). Expressions of EMT markers (TWIST1, Snail, and SNIP1) and MET/hepatocyte growth factor were also analyzed. Staining of the TMA sections showed 78.5% concordance rate to the whole section. PD-L1 positivity and its intratumoral heterogeneity were 29.1% and 15.2% of TSCCs by whole section, respectively. PD-L1 positivity was prevalent in females, HPV-positive tumors without base of tongue invasion, and SNIP1-overexpressed tumors. SNIP1 overexpression, unmethylated TWIST1, smoking, and poorly differentiated tumors were predictive for PD-L1 overexpression. PD-L1 positivity was a favorable independent prognostic factor. Subgroup analyses according to the coexpression of PD-L1 with HPV, SNIP1, or unmethylated TWIST1 indicated the best clinical outcome than any other subgroups. In conclusion, intratumoral heterogeneity of PD-L1 expression was frequent, warranting a caution in punching TMA cores. A combined analysis of PD-L1 with EMT and HPV may define a characteristic subset of patients and prognostic group., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: This study examined the relationship between sleep duration, sleep quality and food consumption among adolescents., Design: Cross-sectional study., Setting: Data from the 2014 and 2015 Korea Youth Risk Behavior Web-based Survey were used., Participants: Participants aged 12-18 years (n=118 462 (59 431 males and 59 031 females)) were selected., Primary and Secondary Outcome Measures: Sleep duration, sleep quality and the frequencies of fruits, soda, soft drinks, fast food, instant noodle, confectionaries, vegetables and milk consumption., Results: Short sleep durations (<6 hours) were associated with higher soft drinks and confectionaries intake than longer sleep durations (9+ hours) (adjusted ORs (AORs) (95% CIs) for ≥5 times a week for soft drinks: 1.73 (1.57 to 1.91) and confectionaries: 1.32 (1.20 to 1.46); p<0.001). Poor sleep quality, with 7-8 hours of sleep, was associated with a lower intake of fruits, vegetables and milk (AORs (95% CIs) for ≥5 times a week for fruits: 0.71 (0.65 to 0.77); vegetables: 0.66 (0.58 to 0.75); and milk: 0.80 (0.74 to 0.86); each p<0.001), and higher intake of soda, soft drinks, fast food, instant noodle and confectionaries (AORs (95% CIs) for ≥5 times a week for soda: 1.55 (1.40 to 1.70); soft drinks: 1.58 (1.43 to 1.73); fast food: 1.97 (1.65 to 2.35); instant noodle: 1.55 (1.37 to 1.76); and confectionaries: 1.30 (1.18 to 1.43); each p<0.001) than good sleep quality of the same duration., Conclusion: Short sleep durations and poor sleep quality might be associated with higher consumption of unhealthier foods, such as sugar-sweetened beverages, fast food, instant noodle and confectionaries, and associated with lower consumption of fruits, vegetables and milk., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2018. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

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., (Copyright © 2018 Elsevier B.V. All rights reserved.)