Association between high levels of nitrogen dioxide and increased cumulative incidence of lung cancer in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Lung cancer is a fatal complication of idiopathic pulmonary fibrosis (IPF) with a poor prognosis. However, the association between individual exposure to air pollutants and lung cancer development in patients with IPF is unknown. This study aimed to assess the effect of individual exposure to nitrogen dioxide (NO2) on lung cancer development in patients with IPF. METHODS: We enrolled 1085 patients from an IPF cohort in the Republic of Korea (mean age 65.6 years, males 80.6%). We estimated individual-level long-term exposures to NO2 at the patients' residential addresses using a national-scale exposure prediction model based on data from air quality regulatory monitoring stations. To evaluate the association between NO2 levels and lung cancer development in IPF, we used an individual- and area-level covariates adjusted model as our primary model. RESULTS: The estimated average annual NO2 concentration was 23.1 ppb. During a median follow-up of 4.3 years, 86 patients (7.9%) developed lung cancer. NO2 concentration was associated with lung cancer development in an unadjusted model (HR 1.219; p=0.042), while a marginal association was found in the primary model (HR 1.280; p=0.084). When NO2 concentration was stratified by the median value (21.0 ppb), exposure to high NO2 levels (≥21.0 ppb) was associated with a 2.0-fold increase in the risk of lung cancer development (HR 2.023; p=0.047) in the primary model. CONCLUSION: Individual exposure to high NO2 levels may increase the risk of lung cancer development in patients with IPF.

Impact of ambient temperature on respiratory disease: a case-crossover study in Seoul.

BACKGROUND: Respiratory diseases contribute to global morbidity and mortality, and temperature is a significant factor. We investigated the association between ambient temperature and emergency department (ED) visits for various respiratory diseases in Seoul, South Korea. METHODS: Using data from the National Emergency Department Information System (2008-2017), we analysed 1,616,644 ED visits for respiratory diseases, categorised according to the Korean Standard Classification of Diseases 7th revision codes (J00-J99). Using a time-stratified case-crossover design and a distributed lag nonlinear model, we investigated the effect of temperature exposure on ED visits for respiratory diseases, calculating the relative risk (RR) for the maximum risk temperature (MaxRT) of both cold and hot extremes compared to the minimum risk temperature (MinRT). RESULTS: Cold temperatures (MaxRT: -9.0 °C) resulted in a 2.68-fold increase (RR = 2.68, 95% CI = 2.26-3.14) in ED visits for total respiratory diseases, while hot temperatures (MaxRT: 29.4 °C) led to a 1.26-fold increase (RR = 1.26, 95% CI = 1.11-1.42) compared to the MinRT (24.8 °C). Cold temperatures increased the risk of most respiratory diseases, except interstitial lung disease, whereas hot temperatures increased ED visits for acute upper respiratory infections and influenza. Cold temperatures increased ED visits for all age groups, especially those aged 18-64 (RR = 3.54, 95% CI = 2.90-4.33), while hot temperatures significantly affected those < 18 (RR = 1.45, 95% CI = 1.27-1.66). The risk levels were similar in both males and females, regardless of hot and cold temperatures. CONCLUSION: Our findings underscore the significant impact of both cold and heat exposure on ED visits for respiratory diseases, with varying intensities and risk profiles across different population groups.

Smoking status and clinical outcome in idiopathic pulmonary fibrosis: a nationwide study.

BACKGROUND: Smoking status has been linked to the development of idiopathic pulmonary fibrosis (IPF). However, the effect of smoking on the prognosis of patients with IPF is unclear. We aimed to investigate the association between smoking status and all-cause mortality or hospitalisation by using national health claims data. METHODS: IPF cases were defined as people who visited medical institutions between January 2002 and December 2018 with IPF and rare incurable disease exempted calculation codes from the National Health Insurance Database. Total 10,182 patients with available data on smoking status were included in this study. Ever-smoking status was assigned to individuals with a history of smoking ≥ 6 pack-years. The multivariable Cox proportional hazard model was used to evaluate the association between smoking status and prognosis. RESULTS: In the entire cohort, the mean age was 69.4 years, 73.9% were males, and 45.2% were ever smokers (current smokers: 14.2%; former smokers: 31.0%). Current smokers (hazard ratio [HR]: 0.709; 95% confidence interval [CI]: 0.643-0.782) and former smokers (HR: 0.926; 95% CI: 0.862-0.996) were independently associated with all-cause mortality compared with non-smokers. Current smokers (HR: 0.884; 95% CI: 0.827-0.945) and former smokers (HR: 0.909; 95% CI: 0.862-0.959) were also associated with a reduced risk of all-cause hospitalisation compared with non-smokers. A non-linear association between smoking amount and prognosis was found in a spline HR curve and showed increasing risk below 6 pack-years. CONCLUSION: Ever-smoking status may be associated with favourable clinical outcomes in patients with IPF.

Nitrogen dioxide increases the risk of disease progression in idiopathic pulmonary fibrosis.

BACKGROUND AND OBJECTIVE: Air pollution affects clinical course and prognosis of idiopathic pulmonary fibrosis (IPF). However, the effect of individual exposure to air pollutants on disease progression is unclear. We aimed to identify the effect of individual exposure to nitrogen dioxide (NO2 ) and particulate matter (aerodynamic diameter ≤ 10 µm [PM10 ]) on disease progression in patients with IPF. METHODS: The serial lung function data of 946 IPF patients (mean age: 65.4 years, male: 80.9%) were analysed. Individual-level long-term exposures to NO2 and PM10 at the residential addresses of patients were estimated using a national-scale exposure prediction model, constructed based on air quality regulatory monitoring data. Progression was defined as a relative decline (≥10%) in forced vital capacity. Individual- and area-level covariates were adjusted in the primary analysis model. RESULTS: Overall, 547 patients (57.8%) experienced progression during a median follow-up of 1.0 year (interquartile range: 0.4-2.6 years). In the primary model, a 10-ppb increase in NO2 concentration was associated with a 10.5% increase in the risk of progression (hazard ratio [HR] = 1.105; 95% CI = 1.000-1.219) in patients with IPF. There was also an increasing trend of progression in patients with IPF according to the second to fourth quartiles of NO2 (Q2 [HR = 1.299; 95% CI = 0.972-1.735], Q3 [1.409; 1.001-1.984], Q4 [1.598; 1.106-2.310]) compared to the first quartile. We found no association between PM10 and progression in IPF patients. CONCLUSION: Our data suggest that increased individual exposure to NO2 can increase the risk of progression in patients with IPF.

Long-term clinical course and outcomes in patients with lymphangioleiomyomatosis.

BACKGROUND: Lymphangioleiomyomatosis (LAM) is a rare multisystemic disorder with various clinical manifestations. Despite the recognition of several prognostic factors, the long-term clinical course and prognosis of patients with LAM in the era of sirolimus therapy are not established. METHODS: The clinical data of 104 patients with LAM were retrospectively analyzed. Death or lung transplantation was defined as the primary outcome. Disease progression (DP) was defined as a 10% absolute decline in forced expiratory volume in one second (FEV1). RESULTS: The mean age of all patients was 40.3 years. Over a median follow-up period of 7.1 years, of all patients, 6.7% died and 1.9% underwent lung transplantation, while of 92 patients with serial lung function data, 35.9% experienced DP. The 5-year and 10-year overall survival rates were 93.0% and 90.9%, respectively. The multivariable Cox analysis revealed that older age (hazard ratio [HR]: 1.136, P = 0.025), lower FEV1 (HR: 0.956, P = 0.026) or diffusing capacity for carbon monoxide (HR: 0.914, P = 0.003), and shorter distance during the 6-min walk test (HR: 0.993, P = 0.020) were independent prognostic factors for mortality. A propensity score-matched comparative analysis performed between patients who received sirolimus therapy and those who did not, found no differences in survival, DP, complications, and lung function decline rate. CONCLUSIONS: Over a follow-up period of approximately 7 years, one-tenth of all patients experienced death, while one-third experienced DP. Older age, lower lung function, and reduced exercise capacity were associated with a poor prognosis in patients with LAM.

Nitrogen dioxide increases the risk of mortality in idiopathic pulmonary fibrosis.

Ambient air pollution is associated with the prognosis of idiopathic pulmonary fibrosis (IPF) patients. We aimed to identify the impacts of individual exposure to particulate matter with a 50% cut-off aerodynamic diameter of 10 µm (PM10) and nitrogen dioxide (NO2) on IPF patients' mortality.1114 patients (mean age 65.7 years; male 80.5%) diagnosed with IPF between 1995 and 2016 were included in this study. Individual-level long-term concentrations of PM10 and NO2 at residential addresses of patients were estimated using a national-scale exposure prediction model. The effect of PM10 and NO2 on mortality was estimated using a Cox proportional hazards model adjusted for individual- and area-level covariates.The median follow-up period was 3.8 years and 69.5% of the patients died or underwent lung transplantation. When adjusted for individual- and area-level covariates, a 10 ppb increase in NO2 concentration was associated with a 17% increase in mortality (hazard ratio (HR) 1.172, 95% CI 1.030-1.344; p=0.016). When IPF patients were stratified by age (≥65 versus <65 years) or by sex, NO2 was a significant prognostic factor for mortality in the elderly (HR 1.331, 95% CI 1.010-1.598; p=0.010). When stratified by age and sex jointly, NO2 showed the stronger association with mortality in elderly males (HR 1.305, 95% CI 1.072-1.598; p=0.008) than in other groups. PM10 was not associated with IPF mortality in all patients and in subgroups stratified by age or sex.Our findings suggest that increased exposure to NO2 can increase the risk of mortality in patients with IPF, specifically in elderly males.

18F-FDG PET/CT predicts acute exacerbation in idiopathic pulmonary fibrosis after thoracic surgery.

BACKGROUND: Acute exacerbation (AE) is the most lethal postoperative complication in idiopathic pulmonary fibrosis (IPF); however, prediction before surgery is difficult. We investigated the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in predicting postoperative AE in IPF. METHOD: Clinical data of 48 IPF patients who underwent 18F-FDG PET/CT before thoracic surgery were retrospectively analyzed. Mean and maximal standardized uptake values (SUVmean and SUVmax, respectively) were measured in the fibrotic area. Additionally, adjusted values-SUV ratio (SUVR, defined as SUVmax-to-liver SUVmean ratio), tissue fraction-corrected SUVmean (SUVmeanTF), and SUVR (SUVRTF)-were calculated. RESULTS: The mean age of the subjects was 67.8 years and 91.7% were male. After thoracic surgery, 21 (43.8%) patients experienced postoperative complications including prolonged air leakage (29.2%), death (14.6%), and AE (12.5%) within 30 days. Patients who experienced AE showed higher SUVmax, SUVR, SUVmeanTF, and SUVRTF than those who did not, but other clinical parameters were not different between patients with and without AE. The SUV parameters did not differ for other complications. The SUVR (odds ratio [OR] 29.262; P = 0.030), SUVmeanTF (OR 3.709; P = 0.041) and SUVRTF (OR 20.592; P = 0.017) were significant predicting factors for postoperative AE following a multivariate logistic regression analysis. On receiver operating characteristics curve analysis, SUVRTF had the largest area under the curve (0.806, P = 0.007) for predicting postoperative AE among SUV parameters. CONCLUSIONS: Our findings suggest that 18F-FDG PET/CT may be useful in predicting postoperative AE in IPF patients and among SUVs, SUVRTF is the best parameter for predicting postoperative AE in IPF patients.

The Value of 18F-FDG PET/CT in Evaluating Disease Severity and Prognosis in Idiopathic Pulmonary Fibrosis Patients.

BACKGROUND: Several parameters are useful for assessing disease severity in idiopathic pulmonary fibrosis (IPF); however, the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is not well-defined. We aimed to evaluate the value of 18F-FDG PET/CT for assessing disease severity and prognosis in IPF patients. METHODS: Clinical data of 89 IPF patients (mean age: 68.1 years, male: 94%) who underwent 18F-FDG PET/CT for evaluation of lung nodules or cancer staging were retrospectively reviewed. Mean and maximal standardized uptake values (SUVmean, SUVmax, respectively) were measured in the fibrotic area. Adjusted SUV, including SUV ratio (SUVR, defined as SUVmax-to-liver SUVmean ratio), tissue fraction-corrected SUVmean (SUVmeanTF), and SUVR (SUVRTF), and tissue-to-blood ratio (SUVmax/SUVmean venous; TBRblood) were obtained. Death was defined as the primary outcome, and associations between other clinical parameters (lung function, exercise capacity, C-reactive protein [CRP] level) were also investigated. RESULTS: All SUV parameters were inversely correlated with the forced vital capacity, diffusing capacity for carbon monoxide, and positively correlated with CRP level and the gender-age-physiology index. The SUVmean, SUVmax, and SUVmeanTF were associated with changes in lung function at six months. The SUVR (hazard ratio [HR], 1.738; 95% confidence interval [CI], 1.011-2.991), SUVRTF (HR, 1.441; 95% CI, 1.000-2.098), and TBRblood (HR, 1.377; 95% CI, 1.038-1.827) were significant predictors for mortality in patients with IPF in the univariate analysis, but not in the multivariate analysis. CONCLUSION: 18F-FDG PET/CT may provide additional information on the disease severity and prognosis in IPF patients, and the SUVR may be superior to other SUV parameters.

Pulmonary alveolar proteinosis in Korea: analysis of prevalence and incidence via a nationwide population-based study.

BACKGROUND: Pulmonary alveolar proteinosis (PAP) is a very rare lung disease and its prevalence and incidence remain unclear. The prevalence and incidence of PAP were investigated by using nationwide claims data from the Korean Health Insurance Review and Assessment service. METHODS: Data were extracted for adults who visited any secondary or tertiary medical institute between 2010 and 2016 with the PAP-related Korean Classification of Disease, 7th edition code J84.0 and the Rare Intractable Disease exempted calculation code V222. To robust case definition, a narrow case definition was made when all following factors were met: 1) more than two PAP-coded visits within 1 year of the first claim, and 2) more than one claim for both chest computed tomography and diagnostic procedures (bronchoscopy or surgical lung biopsy) within 90 days before or after the first claim. RESULTS: A total of 182 patients (narrow, n = 82) with PAP-related codes were identified from 2010 to 2016 and 89 new patients (narrow, n = 66) visited medical institutes between 2012 and 2015. The prevalence of PAP was 4.44 (narrow: 2.27) per 106 population, with a peak age of 60-69 years. The incidence of PAP was 0.56 (narrow: 0.41) per 106 population at risk, with a peak age of 50-59 years. Among incident cases, the male-to-female ratio was 1.52 and about two-thirds had comorbidities, dyslipidaemia being the most common. CONCLUSIONS: The prevalence and incidence of PAP in Korea are low, similar to those in other countries; however, Korean patients with PAP are characterized by older diagnostic age and a lower male-to-female ratio.

Effects of emphysema on physiological and prognostic characteristics of lung function in idiopathic pulmonary fibrosis.

BACKGROUND AND OBJECTIVE: Combined pulmonary fibrosis and emphysema (CPFE) is characterized by preserved lung volume and slower lung function decline. However, it is unclear at what extent emphysema begins to impact respiratory physiology and prognostic characteristics in idiopathic pulmonary fibrosis (IPF). We estimated the extent of emphysema that could be used to define CPFE in IPF. METHODS: The extent of emphysema was observed on high-resolution computed tomography scans and measured by a texture-based automated quantification system in 209 IPF patients. We analysed the impact of differences in the extent of emphysema on the annual decline rate and prognostic significance of lung function parameters. RESULTS: The extent of emphysema was ≥5% in 53 patients (25%), ≥10% in 23 patients (11%) and ≥15% in 12 patients (6%). Patients with emphysema to an extent of ≥5% were more frequently men and ever-smokers; they had more preserved lung volume and lower forced vital capacity (FVC) decline rates than those with no or trivial emphysema. The FVC decline rate was a significant predictor of mortality in patients with no or trivial emphysema (hazard ratio (HR): 0.933, P < 0.001) and in patients with an extent of emphysema ≥5% (HR: 0.906, P < 0.001). However, diffusing capacity of the lung for carbon monoxide (DLCO ) was the most significant prognostic factor in those patients with an extent of emphysema ≥10% (HR: 0.972, P = 0.040) and ≥15% (HR: 0.942, P = 0.023). A 10% cut-off value for the extent of emphysema created the most significant difference in the annual FVC decline rate in IPF patients. CONCLUSION: In IPF, emphysema to an extent of ≥10% affects both the annual decline rate and the prognostic significance of FVC. This extent could be used to define CPFE.

Efficacy and Safety of Pirfenidone in Advanced Idiopathic Pulmonary Fibrosis.

BACKGROUND: Although phase 3 trials showed significant efficacy and acceptable safety profiles for pirfenidone in mild-to-moderate idiopathic pulmonary fibrosis (IPF), data on advanced IPF are limited. OBJECTIVES: The study aimed to evaluate the efficacy and safety of pirfenidone in advanced IPF patients. METHODS: The clinical data of 138 IPF patients (advanced group: 27%) treated with pirfenidone were retrospectively reviewed and compared between advanced and non-advanced groups. Advanced IPF was defined as (1) forced vital capacity (FVC) < 50% predicted or (2) diffusing capacity for carbon monoxide < 30% predicted. RESULTS: The mean treatment duration was 51.3 weeks, and lung function analysis was performed in 81 patients (17 in the advanced group). Changes in FVC and total lung capacity (TLC) were significantly reduced at 6 months after treatment in both the advanced (ΔFVC [6 months]: -6.3 [before] vs. 0.7% predicted [after]; ΔTLC: -5.3 vs. 0.8) and non-advanced (ΔFVC: -3.4 vs. 0.5; ΔTLC: -3.1 vs. -0.9) groups. The rate of decline in FVC and TLC was significant before treatment, but not after treatment in the advanced (FVC: -1.27 [before] vs. 0.21% predicted/month [after]; TLC: -0.89 vs. -0.15) and non-advanced (FVC: -0.60 vs. -0.20; TLC: -0.54 vs. -0.17) groups. The advanced group showed a similar rate of adverse events (AEs) (78.4 vs. 88.1%, p = 0.270), but more serious AEs (40.5 vs. 10.9%, p < 0.001) including death (24.3 vs. 5.0%, p = 0.002). CONCLUSIONS: In advanced IPF, pirfenidone showed similar efficacy and safety to non-advanced IPF except for serious AEs, which may be due to the advanced status itself.

Spontaneous remission of advanced progressive poorly differentiated non-small cell lung cancer: a case report and review of literature.

BACKGROUND: Spontaneous remission (SR) of cancer is a very rare phenomenon of unknown mechanism. In particular, SR of non-small cell lung cancer (NSCLC) has been scarcely reported. We present the case of a 74-year-old woman with advanced, poorly differentiated NSCLC (highly expressing programmed death ligand-1 [PD-L1]) that progressed despite multiple lines of chemotherapy but then spontaneously remitted. CASE PRESENTATION: The patient presented with hemoptysis and was diagnosed with stage IIIA poorly differentiated NSCLC via bronchoscopic biopsy. She had an unremarkable medical history and moderate performance status. The initial treatment plan was surgery after neoadjuvant chemotherapy. Despite conventional chemotherapy, follow-up chest computed tomography (CT) showed gradual tumor progression and she decided against further treatment after fifth-line chemotherapy. However, the size of lung mass was markedly decreased on follow-up chest CT one year after ceasing chemotherapy. Also, follow-up positron emission tomography images showed decreased metabolic activity in the lung mass and a percutaneous biopsy specimen from the diminished lung mass revealed no viable tumor cells. A diagnosis of SR of NSCLC was confirmed, and the patient was without tumor progression on follow-up nine months later. Later, PD-L1 immunostaining revealed high positivity (> 99%) in initial tumor cells. CONCLUSION: Our case showing SR of poorly advanced NSCLC refractory to multiple lines of chemotherapy suggested the association between immunity and tumor regression.

Hemoptysis requiring bronchial artery embolization in patients with nontuberculous mycobacterial lung disease.

BACKGROUND: Although infections caused by nontuberculous mycobacteria (NTM) are increasing in prevalence, there are few data about hemoptysis in patients with NTM lung disease. This study investigated the characteristics and prognosis of hemoptysis secondary to NTM infection. METHODS: Following a retrospective review of cases managed between 2006 and 2016, 183 patients with NTM lung disease were enrolled and analyzed. RESULTS: Among 183 patients with NTM lung disease, Mycobacterium intracellulare (n = 64, 35%) was the major cause of NTM infection, followed by M. avium (n = 59, 32.2%) and M. abscessus complex (n = 40, 21.9%). Hemoptysis developed in 78 patients (42.6%), among whom 33 (42.3%) required bronchial artery embolization (BAE). Between patients with and without hemoptysis, there were no significant differences with respect to sex, radiographic manifestations, distribution over 3 lobes on chest computed tomography, history of pulmonary tuberculosis, antiplatelet or anticoagulation therapy, and species of NTM. However, mean age at diagnosis was significantly lower in the hemoptysis group in univariate and multivariate analyses (65.7 ± 12.8 vs. 59.7 ± 11.8, P = 0.002, odds ratio: 0.969, 95% confidence interval: 0.944-0.996). Among patients with hemoptysis, those requiring medical therapy and those requiring BAE were not significantly different in terms of demographic characteristics, radiographic manifestations, and distribution over 3 lobes. All patients who received BAE showed immediate clinical improvement, no procedure-related complications, and none of them died during the period under review. CONCLUSIONS: NTM lung disease patients commonly experienced hemoptysis without specific risk factors except for relatively young age. Although some patients with hemoptysis needed BAE, the success rate of BAE was high, and there were no serious complications associated with BAE.

Efficacy and safety of nintedanib in advanced idiopathic pulmonary fibrosis.

BACKGROUND: Phase 3 trials have shown that nintedanib reduces the decline in forced vital capacity (FVC) in patients with mild-to-moderate idiopathic pulmonary fibrosis (IPF) with acceptable safety profiles; however, its effects on advanced IPF are unclear. We investigated the efficacy and safety of nintedanib in patients with advanced IPF. METHODS: Prospective data were obtained from 108 IPF patients administered at least one dose of nintedanib. Of these patients, 47.2% had advanced IPF (FVC < 50% predicted, or diffusing capacity < 30% predicted). RESULTS: The median treatment duration was 42.2 weeks. Nintedanib significantly reduced the decline rate in both FVC (- 0.55% [before] vs. -0.32% [after] predicted/month, p = 0.020) and total lung capacity (TLC) (- 0.35% vs. -0.06% predicted/month, p < 0.001) in all patients. A significant improvement in FVC decline rate after treatment was also observed in the advanced group (- 0.77% vs. -0.22% predicted/month, p = 0.003), but not in the non-advanced group (- 0.41% vs. -0.33% predicted/month, p = 0.564). Adverse events occurred in 97.2% of the cohort, including diarrhoea (50.0%) and anorexia (45.4%). Following adjustment for treatment duration, no inter-group difference in odds ratio was observed for the occurrence of adverse events. However, the advanced group showed a higher frequency of treatment interruption (68.0% vs. 40.0%), mainly as a result of disease progression (47.1% vs. 36.4%). CONCLUSIONS: The efficacy and safety profiles of nintedanib in the advanced group were comparable to those in the non-advanced group except for a higher frequency of discontinuation, which may be due to the advanced status itself.

Prevalence and incidence of sarcoidosis in Korea: a nationwide population-based study.

BACKGROUND: The prevalence and incidence of sarcoidosis varies worldwide. We estimated the prevalence and incidence of sarcoidosis in Korea using nationwide claims data from the Korean Health Insurance Review and Assessment Service. METHODS: Cases of sarcoidosis were identified for any visit between 2007 to 2016 that listed the Korean Classification of Disease, 7th edition code of sarcoidosis and rare incurable disease exempted calculation code. A narrow case definition was used as follows: 1) ≥ two sarcoidosis-coded visits within 1 year of the first claim, 2) no claims for other diseases that could form granuloma. RESULTS: A total of 4791 patients (narrow, n = 2388) visited medical institutions for sarcoidosis during the study period; 2999 patients (narrow, n = 1696) were newly identified between 2009 and 2015. The sarcoidosis prevalence was 9.37 per 105 people (narrow, 4.69) and was highest between ages 60-69 years. The incidence rate was 0.85 per 105 population at risk (narrow, 0.48), with the highest incidence rate between ages 50-59 years. For incident cases (mean age: 48.5 year), the age distribution in whole population and females showed monophasic patterns peaking at aged 50-59 years, while males had biphasic incidence peak at aged 30-39 years and 60-69 years. The annual incidence rates showed increasing trends from 0.85 per 105 population at risk in 2009 to 0.97 per 105 population at risk in 2015. CONCLUSIONS: In comparison with previous reports, the prevalence and incidence of sarcoidosis in Korea have increased and middle-aged women showed the highest risk.

Association between the Risk of Obstructive Sleep Apnea and Lung Function: Korea National Health and Nutrition Examination Survey.

BACKGROUND: Obstructive sleep apnea (OSA) is a prevalent sleep disorder associated with various health issues. Although some studies have suggested an association between reduced lung function and OSA, this association remains unclear. Our study aimed to explore this relationship using data from a nationally representative population- based survey. METHODS: We performed an analysis of data from the 2019 Korea National Health and Nutrition Examination Survey. Our study encompassed 3,675 participants aged 40 years and older. Risk of OSA was assessed using the STOP-Bang (Snoring, Tiredness during daytime, Observed apnea, and high blood Pressure-Body mass index, Age, Neck circumference, Gender) questionnaire and lung function tests were performed using a portable spirometer. Logistic regression analysis was applied to identify the risk factors associated with a high-risk of OSA, defined as a STOP-Bang score of ≥3. RESULTS: Of 3,675 participants, 600 (16.3%) were classified into high-risk OSA group. Participants in the high-risk OSA group were older, had a higher body mass index, and a higher proportion of males and ever-smokers. They also reported lower lung function and quality of life index in various domains along with increased respiratory symptoms. Univariate logistic regression analysis indicated a significant association between impaired lung function and a high-risk of OSA. However, in the multivariable analysis, only chronic cough (odds ratio [OR], 2.413; 95% confidence interval [CI], 1.383 to 4.213) and sputum production (OR, 1.868; 95% CI, 1.166 to 2.992) remained significantly associated with a high OSA risk. CONCLUSION: Our study suggested that, rather than baseline lung function, chronic cough, and sputum production are more significantly associated with OSA risk.

Effects of indoor air pollution on clinical outcomes in patients with interstitial lung disease: protocol of a multicentre prospective observational study.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrosing interstitial lung disease with a poor prognosis. While there is evidence suggesting that outdoor air pollution affects the clinical course of IPF, the impact of indoor air pollution on patients with IPF has not been extensively studied. Therefore, this prospective multicentre observational study aims to investigate the association between indoor air pollution and clinical outcomes in patients with IPF. METHODS AND ANALYSIS: This study enrolled 140 patients with IPF from 12 medical institutes in the Seoul and Metropolitan areas of the Republic of Korea. Over the course of 1 year, participants visited the institutes every 3 months, during which their clinical data and blood samples were collected. Additionally, indoor exposure to particulate matter ≤2.5 µm (PM2.5) was measured using MicroPEM (RTI International, Research Triangle Park, North Carolina, USA) in each participant's house for 5 days every 3 months. Lung function was assessed using both site spirometry at each institution and portable spirometry at each participant's house every 3 months. The study will analyse the impact of indoor PM2.5 on clinical outcomes, including mortality, acute exacerbation, changes in lung function and health-related quality of life, in the participants. This study represents the first attempt to evaluate the influence of indoor air pollution on the prognosis of patients with IPF. ETHICS AND DISSEMINATION: This study has received approval from the institutional review board of all participating institutions, including Asan Medical Center, Seoul, Republic of Korea (2021-0072). TRIAL REGISTRATION NUMBER: KCT0006217.