Risk compensation after COVID-19 vaccination: Evidence from vaccine rollout by exact birth date in South Korea.

We utilize the phased rollout of COVID-19 vaccines by exact birth date in South Korea as a natural experiment for testing risk compensation. People may resume face-to-face social activities following vaccination because they perceive lower risk of infection. Applying a regression discontinuity design based on birth date cutoffs for vaccine eligibility, we find no evidence of risk-compensating behaviors, as measured by large, high-frequency data from credit card and airline companies as well as survey data. We find some evidence of self-selection into vaccine take-up based on perception toward vaccine effectiveness and side effects, but the treatment effects do not differ between compliers and never-takers.

Spatiotemporal Analysis of Out-of-Hospital Cardiac Arrest Incidence and Survival Outcomes in Korea (2009-2021).

BACKGROUND: Out-of-hospital cardiac arrest is a major public health concern in Korea. Identifying spatiotemporal patterns of out-of-hospital cardiac arrest incidence and survival outcomes is crucial for effective resource allocation and targeted interventions. Thus, this study aimed to investigate the spatiotemporal epidemiology of out-of-hospital cardiac arrest in Korea, with a focus on identifying high-risk areas and populations and examining factors associated with prehospital outcomes. METHODS: We conducted this population-based observational study using data from the Korean out-of-hospital cardiac arrest registry from January 2009 to December 2021. Using a Bayesian spatiotemporal model based on the Integrated Nested Laplace Approximation, we calculated the standardized incidence ratio and assessed the relative risk to compare the spatial and temporal distributions over time. The primary outcome was out-of-hospital cardiac arrest incidence, and the secondary outcomes included prehospital return of spontaneous circulation, survival to hospital admission and discharge, and good neurological outcomes. RESULTS: Although the number of cases increased over time, the spatiotemporal analysis exhibited a discernible temporal pattern in the standardized incidence ratio of out-of-hospital cardiac arrest with a gradual decline over time (1.07; 95% credible interval [CrI], 1.04-1.09 in 2009 vs. 1.00; 95% CrI, 0.98-1.03 in 2021). The district-specific risk ratios of survival outcomes were more favorable in the metropolitan and major metropolitan areas. In particular, the neurological outcomes were significantly improved from relative risk 0.35 (0.31-0.39) in 2009 to 1.75 (1.65-1.86) in 2021. CONCLUSION: This study emphasized the significance of small-area analyses in identifying high-risk regions and populations using spatiotemporal analyses. These findings have implications for public health planning efforts to alleviate the burden of out-of-hospital cardiac arrest in Korea.

Modified susceptible-exposed-infectious-recovered model for assessing the effectiveness of non-pharmaceutical interventions during the COVID-19 pandemic in Seoul.

Susceptible-exposed-infectious-recovered (SEIR) models were applied to assess the effectiveness of non-pharmaceutical interventions (NPIs) and to study the dynamic behavior of the COVID-19 pandemic. Recently, SEIR models have evolved to address the change of human mobility by some NPIs for predicting the new confirmed cases. However, the models have serious limitations when applied to Seoul. Seoul has two representative quarantine policies, i.e. social distancing and the ban on gatherings. Effects of the two policies need to be reflected in different functional forms in the model because changes in human mobility do not fully reflect the ban on gatherings. Thus we propose a modified SEIR model to assess the effectiveness of social distancing, ban on gatherings and vaccination strategies. The application of the modified SEIR model was illustrated by comparing the model output with real data.

Mediators of the Effect of Obesity on Stroke and Heart Disease Risk: Decomposing Direct and Indirect Effects.

BACKGROUND: The prevalence of overweight and obesity are well known risk factors of atherosclerotic cardiovascular disease (ASCVD). We aimed to examine the association between body mass index (BMI) and ASCVD over a 23-year follow-up in young adults. We also qualified how much of the effects of obesity on ASCVD were mediated through blood pressure, cholesterol, and glucose. METHODS: Data are from the Korean Life Course Health Study, a cohort study of 226,955 Korean young adults aged 20-39. At baseline, the participants undertook routine health assessments where their BMI was measured in 1992-1994; and the metabolic mediators including systolic blood pressure (SBP), fasting serum glucose (FSG), and total cholesterol (TC) were re-measured in 2002-2004. The main outcomes of the study include incident events of ischemic heart disease (IHD), stroke, and ASCVD between 2005 and 2015. Cox proportional model was used to calculate adjusted hazard ratios (HRs) for ASCVD. RESULTS: In both men and women, the direct effect of BMI on ASCVD was greater than the indirect effect. The percentage of excess HR of BMI mediated by all of the metabolic mediators, including SBP, FSG, and TC, was 45.7% for stroke and 18.7% for IHD in men and 27.5% for stroke and 17.6% for IHD in women. CONCLUSION: High BMI in young adults increases the risk of metabolic mediators in their middle age, and metabolic mediators explain the adverse effects of high BMI on stroke risk than IHD risk.

Circulating Vitamin D Level and Risk of Sudden Cardiac Death and Cardiovascular Mortality: A Dose-Response Meta-Analysis of Prospective Studies.

BACKGROUND: We conducted a comprehensive meta-analysis of prospective cohort studies to analyze the effect of circulating vitamin D level on the risk of sudden cardiac death (SCD) and cardiovascular disease (CVD) mortality. METHODS: Prospective cohort studies evaluating the association between circulating vitamin D and risk of SCD and CVD mortality were systematically searched in the PubMed and Embase. Extracted data were analyzed using a random effects model and results were expressed in terms of hazard ratio (HR) and 95% confidence interval (CI). Restricted cubic spline analysis was used to estimate the dose-response relationships. RESULTS: Of the 1,321 records identified using the search strategy, a total of 19 cohort studies were included in the final meta-analysis. The pooled estimate of HR (95% CI) for low vs. high circulating vitamin D level was 1.75 (1.49-2.06) with I² value of 30.4%. In subgroup analysis, strong effects of circulating vitamin D were observed in healthy general population (pooled HR, 1.84; 95% CI, 1.43-2.38) and the clinical endpoint of SCD (pooled HRs, 2.68; 95% CI, 1.48-4.83). The dose-response analysis at the reference level of < 50 nmol/L showed a significant negative association between circulating vitamin D and risk of SCD and CVD mortality. CONCLUSION: Our meta-analysis of prospective cohort studies showed that lower circulating vitamin D level significantly increased the risk of SCD and CVD mortality.

Stratifying non-small cell lung cancer patients using an inverse of the treatment decision rules: validation using electronic health records with application to an administrative database.

BACKGROUND: To validate a stratification method using an inverse of treatment decision rules that can classify non-small cell lung cancer (NSCLC) patients in real-world treatment records. METHODS: (1) To validate the index classifier against the TNM 7th edition, we analyzed electronic health records of NSCLC patients diagnosed from 2011 to 2015 in a tertiary referral hospital in Seoul, Korea. Predictive accuracy, stage-specific sensitivity, specificity, positive predictive value, negative predictive value, F1 score, and c-statistic were measured. (2) To apply the index classifier in an administrative database, we analyzed NSCLC patients in Korean National Health Insurance Database, 2002-2013. Differential survival rates among the classes were examined with the log-rank test, and class-specific survival rates were compared with the reference survival rates. RESULTS: (1) In the validation study (N = 1375), the overall accuracy was 93.8% (95% CI: 92.5-95.0%). Stage-specific c-statistic was the highest for stage I (0.97, 95% CI: 0.96-0.98) and the lowest for stage III (0.82, 95% CI: 0.77-0.87). (2) In the application study (N = 71,593), the index classifier showed a tendency for differentiating survival probabilities among classes. Compared to the reference TNM survival rates, the index classification under-estimated the survival probability for stages IA, IIIB, and IV, and over-estimated it for stages IIA and IIB. CONCLUSION: The inverse of the treatment decision rules has a potential to supplement a routinely collected database with information encoded in the treatment decision rules to classify NSCLC patients. It requires further validation and replication in multiple clinical settings.

Spatiotemporal distribution of varicella in the Republic of Korea.

Varicella is a highly contagious disease caused by the varicella-zoster virus (VZV). Given its tendency to cluster geographically, spatial analyses may provide a better understanding of the pattern of varicella transmission. We investigated the spatial characteristics of varicella in Korea and the risk factors for varicella at a national level. Using national surveillance and demographic data, we examined the spatial distribution of incidence rates and their spatial autocorrelation and calculated Moran's index. Spatial regression analysis was used to identify sociodemographic predictors of varicella incidence at the district level. An increasing tendency in the annual incidence of varicella was observed over a 12-year period (2006-2018), with a surge in 2017. There was a clear positive spatial autocorrelation of the varicella incidence rate during the surveillance period. During 2006-2014, High-High (HH) clusters were mostly confined to the northeast region and neighboring districts. The spatial error model showed that population density had a negative coefficient and childhood percentage, percentage of children under 12 years of age among the total population, had positive coefficient, whereas vaccine coverage was insignificant. The varicella incidence according to geographic region varied with population density, childhood percentage, suggesting the importance of community-level surveillance and monitoring strategies.

Disease severity classification and COVID-19 outcomes, Republic of Korea.

PROBLEM: The surge in coronavirus disease 2019 (COVID-19) cases overwhelmed the health system in the Republic of Korea. APPROACH: To help health-care workers prioritize treatment for patients with more severe disease and to decrease the burden on health systems caused by COVID-19, the government established a system to classify disease severity. Health-care staff in city- and provincial-level patient management teams classified the patients into the different categories according to the patients' pulse, systolic blood pressure, respiratory rate, body temperature and level of consciousness. Patients categorized as having moderate, severe and very severe disease were promptly assigned to beds or negative-pressure isolation rooms for hospital treatment, while patients with mild symptoms were monitored in 16 designated facilities across the country. LOCAL SETTING: The case fatality rate was higher in the city of Daegu and the Gyeongsangbuk-do province (1.6%; 124/7756) than the rest of the country (0.5%; 7/1485). RELEVANT CHANGES: From 25 February to 26 March 2020, the ratio of negative-pressure isolation rooms per COVID-19 patient was below 0.15 in the city of Daegu and the Gyeongsangbuk-do province. In the rest of the country, this ratio decreased from 5.56 to 0.63 during the same period. Before the classification system was in place, eight (15.7%) out of the 51 deaths occurred at home or during transfer from home to health-care institutions. LESSONS LEARNT: Categorizing patients according to their disease severity should be a prioritized measure to ease the burden on health systems and reduce the case fatality rate.

Temporal trends in out-of-hospital cardiac arrest outcomes in men and women from 2008 to 2015: A national observational study.

BACKGROUND: We compared the temporal trends in survival and neurological outcomes after out-of-hospital cardiac arrest (OHCA) in men and women. METHODS: A nationwide, population-based observational study enrolled adults with OHCA of presumed cardiac origin from 2008 to 2015. The main outcomes were survival and neurological recovery. We performed trend analyses of potential risk factors and outcomes. Adjusted odd ratios (aOR) were calculated using multivariate logistic regression analysis after adjusting for confounders. To assess whether outcomes had improved over time in both sexes, we calculated the yearly risk-adjusted survival rates and neurological recovery rate for the study period. RESULTS: We included 121,900 patients in the final analysis. Women comprised 36.2% of the patients. During the study, survival improved in both sexes, from 3.2% to 7.9% in men and from 1.8% to 3.7% in women. Neurological recovery improved in men from 1.1% to 5.9% and in women from 0.7% to 2.3%. The risk-adjusted survival rates increased significantly in men from 3.2% in 2008 to 5.7% in 2015 (p for trend <0.01); these rates did not increase to the same degree in women (from 1.8% in 2008 to 3.4% in 2015; p for trend <0.01). After adjusting for confounders, the risk-adjusted neurological recovery rate increased from 1.1% in 2008 to 4.3% in 2015 (p for trend <0.01) in men. This improvement trend was lower in women (from 0.7% in 2008 to 1.5% in 2015, p for trend <0.01). CONCLUSIONS: The outcomes of OHCA improved in both sexes during the study period. The degree of improvement in outcomes was higher in men than in women.

Prevalence and predictors of heated tobacco products use among male ever smokers: results from a Korean longitudinal study.

BACKGROUND: This study examined sociodemographic and tobacco-related factors of heated tobacco products (HTPs) use among adult ever smokers in South Korea where the sales of HTPs have been rapidly increasing since their launch in June 2017. METHODS: Before the launch of HTPs in Korea, participants comprised male ever smokers (234 current smokers and 37 quitters) who participated in the Korea National Health and Nutrition Examination Survey from 2015 to 2017 through one-to-one interview survey and agreed to participate in the follow-up surveys through telephone in December 2017. Data were analyzed using logistic regression, to explore sociodemographic and smoking behavior-related factors of HTPs use. RESULTS: Overall, 10.7% (29/271) of participants responded to using HTPs and 8.1% (22/271) were current HTPs users at the time of the follow-up survey. Multivariate analysis showed that HTPs use is associated with middle age (36 to 49 years old) (aOR = 3.72, CI = 1.16-12.0) (vs. ≥ 50 years), higher income (4Q vs 1Q: aOR = 2.71, CI = 1.16-6.34), and higher educational level (college or higher: aOR = 2.40, CI = 0.87-6.60). Also, vaping experience at baseline was highly associated with HTPs use (aOR = 3.11, CI = 1.22-7.93 for the former experience; aOR = 9.14, CI = 2.34-35.6 for current). However, smoking amount and level of motivation for smoking cessation were not found to be predictors of future HTPs use when limited to current smokers at baseline. CONCLUSIONS: The results showed that vaping experience regardless of current smoking behavior and higher socioeconomic status were found to be associated with subsequent HTPs use among ever smokers. Further studies are required to explore whether this association is causal.

A Health Information Quality Assessment Tool for Korean Online Newspaper Articles: Development Study.

BACKGROUND: Concern regarding the reliability and accuracy of the health-related information provided by online newspaper articles has increased. Numerous criteria and items have been proposed and published regarding the quality assessment of online information, but there is no standard quality assessment tool available for online newspapers. OBJECTIVE: This study aimed to develop the Health Information Quality Assessment Tool (HIQUAL) for online newspaper articles. METHODS: We reviewed previous health information quality assessment tools and related studies and accordingly developed and customized new criteria. The interrater agreement for the new assessment tool was assessed for 3 newspaper articles on different subjects (colorectal cancer, obesity genetic testing, and hypertension diagnostic criteria) using the Fleiss κ and Gwet agreement coefficient. To compare the quality scores generated by each pair of tools, convergent validity was measured using the Kendall τ ranked correlation. RESULTS: Overall, the HIQUAL for newspaper articles comprised 10 items across 5 domains: reliability, usefulness, understandability, sufficiency, and transparency. The interrater agreement for the article on colorectal cancer was in the moderate to substantial range (Fleiss κ=0.48, SE 0.11; Gwet agreement coefficient=0.74, SE 0.13), while for the article introducing obesity genetic testing it was in the substantial range, with values of 0.63 (SE 0.28) and 0.86 (SE 0.10) for the two measures, respectively. There was relatively low agreement for the article on hypertension diagnostic criteria at 0.20 (SE 0.10) and 0.75 (SE 0.13), respectively. Validity of the correlation assessed with the Kendall τ showed good correlation between tools (HIQUAL vs DISCERN=0.72, HIQUAL vs QUEST [Quality Evaluation Scoring Tool]=0.69). CONCLUSIONS: We developed a new assessment tool to evaluate the quality of health information in online newspaper articles, to help consumers discern accurate sources of health information. The HIQUAL can help increase the accuracy and quality of online health information in Korea.

Association of early-onset diabetes, prediabetes and early glycaemic recovery with the risk of all-cause and cardiovascular mortality.

AIMS/HYPOTHESIS: The increasing incidence of diabetes among young adults is a disease burden; however, the effects of early-onset diabetes, prediabetes and glycaemic recovery on CVD or mortality remain unclear. We aimed to investigate the association of these factors with 10 year all-cause mortality, CVD mortality and CVD incidence in Korean young adults. METHODS: This large and longitudinal cohort study included data from the Korean National Health Insurance Service-National Health Information Database; 2,502,375 young adults aged 20-39 years without diabetes mellitus and CVD at baseline were included. Glycaemic status was measured twice, first in 2002-2003 and second in 2004-2005. Changes in fasting glucose levels were evaluated according to fasting glucose status: normal fasting glucose (NFG; <5.5 mmol/l), impaired fasting glucose (IFG; 5.5-6.9 mmol/l), and diabetic fasting glucose (DFG; ≥7.0 mmol/l). Primary outcomes were all-cause and CVD mortality risk. The secondary outcome was incidence of CVD, including acute myocardial infarction and stroke. All outcomes arose from the 10 year follow-up period 1 Jan 2006 to 31 December 2015. RESULTS: Individuals with NFG at baseline, who were subsequently newly diagnosed with diabetes and prediabetes (IFG), had increased all-cause mortality (HR [95% CI] 1.60 [1.44, 1.78] and 1.13 [1.09, 1.18], respectively) and CVD incidence (1.13 [1.05, 1.23] and 1.04 [1.01, 1.07], respectively). In those with DFG at baseline, early recovery to NFG and IFG was associated with decreased all-cause mortality (0.57 [0.46, 0.70] and 0.65 [0.53, 0.81], respectively) and CVD incidence (0.70 [0.60, 0.81] and 0.78 [0.66, 0.91], respectively). Among patients with IFG at baseline, early recovery to NFG was associated with decreased CVD mortality (0.74 [0.59, 0.93]). CONCLUSIONS/INTERPRETATION: Early-onset diabetes or prediabetes increased CVD risks and all-cause mortality after the 10 year follow-up. Furthermore, recovery of hyperglycaemia could reduce the subsequent 10 year risk for CVD incidence and all-cause mortality. Graphical abstract.

Effect of COVID-19 on Tuberculosis Notification, South Korea.

After South Korea raised its infectious disease alert to the highest level in response to coronavirus disease emergence, tuberculosis notification during the first 18 weeks of 2020 decreased significantly from the same period for each year during 2015-2019. Adequate measures to diagnose, control, and prevent tuberculosis need to be maintained.

The Ability of Different Scoring Systems to Predict Mortality in Chronic Obstructive Pulmonary Disease Patients: A Prospective Cohort Study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality, therefore the prediction of mortality in COPD patients is crucial. In the current study, the abilities of different categorization systems to predict mortality in stable COPD patients from a prospective cohort were compared. METHODS: The ability to predict mortality was compared in terms of discrimination by Harrell's C (HC) index and calibration using graphical comparison among the GOLD (Global Initiative for Chronic Obstructive Lung Disease) 2011, GOLD 2017, GOLD grade, BODE (BMI, Airflow Obstruction, Dyspnea, Exercise), updated BODE, BODEx (BMI, Airflow Obstruction, Dyspnea, Exacerbation), e-BODE (Exacerbation and BODE), ADO (Age, Dyspnea, Airflow Obstruction), COPD prognostic index (CPI), and simplified/optimized B-AE-D (BMI, Acute Exacerbation, Dyspnea) indexes. RESULTS: The study included 520 patients, of whom 63 died during a median 40-month follow-up period. Combined prediction systems exhibited higher discrimination properties than single predictors. The CPI exhibited the highest with a HC of 0.768, followed by the simplified B-AE-D (HC 0.761), ADO (HC 0.760), and optimized B-AE-D (HC 0.756). The BODE and its variants other than the ADO exhibited relatively lower HCs (0.656-0.705), and GOLD exhibited the lowest discrimination ability among the combined indices (HCs 0.628-0.637). Subjective symptom questionnaires such as the modified Medical Research Council (mMRC) scale (HC 0.693) and SGRQ (HC 0.679) exhibited the highest ability to predict mortality among the single indices. CONCLUSION: The ADO, simplified B-AE-D, optimized B-AE-D, and GOLD 2017 exhibited good calibration properties, but the CPI did not. The simplified and optimized B-AE-Ds and the ADO index had good discrimination and calibration properties for the prediction of mortality in stable COPD patients.

Risk of acute exacerbations in chronic obstructive pulmonary disease associated with biomass smoke compared with tobacco smoke.

BACKGROUND: Risk of exacerbations in chronic obstructive pulmonary disease (COPD) associated with biomass smoke has not been well addressed, although biomass smoke is similar in composition to tobacco smoke. METHODS: To investigate whether the risk of exacerbations in COPD associated with biomass smoke differs from that in COPD associated with tobacco smoke, we recruited patients with COPD from two Korean multicenter prospective cohorts. In a multiple linear regression model, the standardized regression coefficient (ß) of biomass smoke exposure ≥25 years was most similar to that (ß') of tobacco smoke exposure ≥10 pack-years (ß = - 0.13 and ß' = - 0.14). We grouped patients with COPD into four categories based on the above cut-offs: Less Tobacco-Less Biomass, Less Tobacco-More Biomass, More Tobacco-Less Biomass, and More Tobacco-More Biomass. The main outcome was the incidence of moderate or severe exacerbations. RESULTS: Among 1033 patients with COPD, 107 were included in Less Tobacco-Less Biomass (mean age: 67 years, men: 67%), 40 in Less Tobacco-More Biomass (mean age: 70 years, men: 35%), 631 in More Tobacco-Less Biomass (mean age: 68 years, men: 98%), and 255 in More Tobacco-More Biomass (mean age: 69 years, men: 97%). The incidence rates of exacerbations were not significantly different between Less Tobacco-More Biomass and More Tobacco-Less Biomass (adjusted incidence rate ratio, 1.03; 95% confidence interval, 0.56-1.89; P = 0.921). No interaction between sex and tobacco and biomass smoke was observed. When propensity score matching with available covariates including age and sex was applied, a similar result was observed. CONCLUSIONS: Patients with COPD associated with biomass smoke and those with COPD associated with tobacco smoke had a similar risk of exacerbations. This suggests that patients with COPD associated with biomass smoke should be treated actively.

The relationship between hormone replacement therapy and periodontal disease in postmenopausal women: a cross-sectional study the Korea National Health and Nutrition Examination Survey from 2007 to 2012.

BACKGROUND: The purpose of this study was to investigate the relationship between hormone replacement therapy (HRT) and periodontal disease in postmenopausal women using data from the 4th and 5th Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: The study included data from 5,482 postmenopausal women aged 45-74 years in the 2007-2012 KNHANES. The use of female HRT for at least one month was reclassified as HRT+/HRT-. The Community Periodontal Index of Treatment Needs (CPITN) was used to assess periodontal status. Propensity score matching (PSM) was used to control selection bias, and factors affecting education, family income, and age of menopause were used as covariates in PSM. A chi-square test was used to confirm the bivariate relationship between the variables. Binary logistic regression analysis was used to adjust for confounders (age, education, family income, body mass index, age of menopause, alcohol, smoking, dental clinic visits in the past one year, use of oral care products and frequency of tooth brushing per day). RESULTS: After adjusting for all covariates, HRT was associated with periodontal disease (OR: 0.79; 95% CI: 0.66-0.94). In particular, the relationship between HRT and periodontal disease was more evident in those with menopause under 45 years of age disease (OR: 0.55; 95% CI: 0.35-0.87). CONCLUSIONS: The results of this study supported that it is important that hormone therapy be actively considered in the policy towards postmenopausal women. Especially, health programs such as hormone replacement therapy, non-smoking, and use of oral care products are needed for women who undergo premature menopause.

Body fat distribution is more predictive of all-cause mortality than overall adiposity.

AIMS: The relationship between directly measured body fat and all-cause mortality has been rarely studied. The aim of this study was to evaluate the predictive significance of computed tomography (CT)-measured body fat, including both visceral fat area (VFA) and subcutaneous fat area (SFA), for mortality. METHODS: The study included 36 656 participants who underwent abdominal CT as part of a health check-up at a single university-affiliated healthcare center in 2007 to 2015. Of those, 32 593 participants with data regarding vital status as of May 2016 were included in the final analysis. The main factors evaluated were VFA, SFA and visceral-to-subcutaneous fat area ratio (VSR), and the primary outcome was all-cause mortality. RESULTS: There were 253 deaths during a mean follow-up of 5.7 years. Increased SFA was associated with decreased all-cause mortality, whereas an increased VFA and VSR were related to increased all-cause mortality. Compared with the predictive power of body mass index (BMI), SFA and VSR showed a larger area under the curve than did BMI. In Kaplan-Meier survival curve analysis, increased SFA and VSR were associated with decreased and increased hazard of all-cause death, respectively. However, in multivariate Cox proportional hazard regression analysis, only VSR was independently associated with all-cause mortality. Moreover, this relationship was paralleled by the harmful impact of increased VSR on metabolic profiles. CONCLUSION: Increased VSR was an independent predictor of all-cause mortality. This suggests that the location of fat deposits may be more important than the actual amount of body fat.

Effects of traffic-related air pollution on susceptibility to infantile bronchiolitis and childhood asthma: A cohort study in Korea.

OBJECTIVE: This study examined the role of exposure to traffic-related air pollution (TRAP) on susceptibility to asthma in children with past episodes of bronchiolitis. METHODS: The baseline data included 2,627 school children aged 6-14 years who had participated in the longitudinal follow-up survey of the Children's Health and Environmental Research of Korea. Lifetime wheezing, past episodes of bronchiolitis, and doctor-diagnosed asthma were evaluated using an International Study of Asthma and Allergies in Childhood questionnaire. We used generalized linear regression with binomial distribution to calculate the relative risk (RR) between TRAP, assessed by proximity to a main road and the total length of roads, and asthma. RESULTS: Compared with the subjects who had less than 100 m of road length within 200-m radius from their home, those with more than 500 m of road length had significantly increased odds for infantile bronchiolitis (adjusted OR [aOR]: 1.57, 95% confidence interval [CI]: 1.01-2.42). Positive exposure-response relationships were found between residential proximity to the main road and asthma (aOR: 1.79, 95% CI: 1.05-3.06; <75 m vs. >700 m from a main road, P for the trend = 0.02). Closer residential proximity to the main road (<75 m) and bronchiolitis combined increased the risks of newly diagnosed asthma (adjusted RR: 3.62, 95% CI: 1.07-12.26) compared with those without bronchiolitis and living ≥ 75 m away from the main road. CONCLUSIONS: TRAP appeared to be associated with an increased asthma among children with bronchiolitis, indicating the importance of modifying effects of bronchiolitis in asthma pathogenesis.

Effect of National Implementation of Telephone CPR Program to Improve Outcomes from Out-of-Hospital Cardiac Arrest: an Interrupted Time-Series Analysis.

BACKGROUND: In cardiac arrest, the survival rate increases with the provision of bystander cardiopulmonary resuscitation (CPR), of which the initial response and treatment are critical. Telephone CPR is among the effective methods that might increase the provision of bystander CPR. This study aimed to describe and examine the improvement of neurological outcomes in individuals with out-of-hospital acute cardiac arrest by implementing the nationwide, standardized telephone CPR program. METHODS: Data from the emergency medical service-based cardiac arrest registry that were collected between 2009 and 2014 were used. The effectiveness of the intervention in the interrupted time-series study was determined via a segmented regression analysis, which showed the risk ratio and risk difference in good neurological outcomes before and after the intervention. RESULTS: Of 164,221 patients, 148,403 were analyzed. However, patients with unknown sex and limited data on treatment outcomes were excluded. Approximately 64.3% patients were men, with an average age of 63.7 years. The number of bystander CPR increased by 3.3 times (95% confidence interval [CI], 3.1-3.5) after the intervention, whereas the rate of good neurological outcomes increased by 2.6 times (95% CI, 2.3-2.9 [1.6%]; 1.4-1.7). The excess number was identified based on the differences between the observed and predicted trends. In total, 2,127 cases of out-of-hospital cardiac arrest (OHCA) after the intervention period received additional bystander CPR, and 339 cases of OHCA had good neurological outcomes. CONCLUSION: The nationwide implementation of the standardized telephone CPR program increased the number of bystander CPR and improved good neurological outcomes.

Cesium-137 Contaminated Roads and Health Problems in Residents: an Epidemiological Investigation in Seoul, 2011.

BACKGROUND: In 2011, two roads in a residential area in Seoul were found to be contaminated with the radionuclide cesium-137 (137Cs). In response to public concerns, an epidemiological study was conducted. METHODS: The standardized cancer incidence ratios in the affected and neighboring regions were calculated based on the central cancer registry. Households in the region were sampled using the random stratified sampling technique, and questionnaires were administered to family members, via home visit and via students in elementary to high schools. Information on duration of residency and frequency of use of the roads was applied to calculate cumulative radiation exposure dose from the roads, alongside with the reported 137Cs contamination amounts. Information on past medical history, perceived risk, anxiety and psychological stress was also obtained. Of the 31,053 residents, 8,875 were analyzed. To examine possible associations between radiation exposure and health problems, logistic regression adjusted for covariates were performed with consideration of the sampling design, population weight and stratification. RESULTS: No significant association was found between self-informed diseases, including cancers, and estimated radiation exposure dose. According to an increase of radiation level, a significant increase in anxiety in all and a decline in the psychosocial wellbeing of the adults was noted. The risk perception level was higher in the elderly, females, the less educated, and the highest exposed individuals. CONCLUSION: This study provides a basis for risk communication with residents and community environmental health policy.