Mortality Burden Due to Short-term Exposure to Fine Particulate Matter in Korea.

OBJECTIVES: Excess mortality associated with long-term exposure to fine particulate matter (PM2.5) has been documented. However, research on the disease burden following short-term exposure is scarce. We investigated the cause-specific mortality burden of short-term exposure to PM2.5 by considering the potential non-linear concentration-response relationship in Korea. METHODS: Daily cause-specific mortality rates and PM2.5 exposure levels from 2010 to 2019 were collected for 8 Korean cities and 9 provinces. A generalized additive mixed model was employed to estimate the non-linear relationship between PM2.5 exposure and cause-specific mortality levels. We assumed no detrimental health effects of PM2.5 concentrations below 15 µg/m3. Overall deaths attributable to short-term PM2.5 exposure were estimated by summing the daily numbers of excess deaths associated with ambient PM2.5 exposure. RESULTS: Of the 2 749 704 recorded deaths, 2 453 686 (89.2%) were non-accidental, 591 267 (21.5%) were cardiovascular, and 141 066 (5.1%) were respiratory in nature. A non-linear relationship was observed between all-cause mortality and exposure to PM2.5 at lag0, whereas linear associations were evident for cause-specific mortalities. Overall, 10 814 all-cause, 7855 non-accidental, 1642 cardiovascular, and 708 respiratory deaths were attributed to short-term exposure to PM2.5. The estimated number of all-cause excess deaths due to short-term PM2.5 exposure in 2019 was 1039 (95% confidence interval, 604 to 1472). CONCLUSIONS: Our findings indicate an association between short-term PM2.5 exposure and various mortality rates (all-cause, non-accidental, cardiovascular, and respiratory) in Korea over the period from 2010 to 2019. Consequently, action plans should be developed to reduce deaths attributable to short-term exposure to PM2.5.

Impact of the early phase of the COVID-19 pandemic on emergency department-to-intensive care unit admissions in Korea: an interrupted time-series analysis.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic resulted in significant disruptions to critical care systems globally. However, research on the impact of the COVID-19 pandemic on intensive care unit (ICU) admissions via the emergency department (ED) is limited. Therefore, this study evaluated the changes in the number of ED-to-ICU admissions and clinical outcomes in the periods before and during the pandemic. METHODS: We identified all adult patients admitted to the ICU through level 1 or 2 EDs in Korea between February 2018 and January 2021. February 2020 was considered the onset point of the COVID-19 pandemic. The monthly changes in the number of ED-to-ICU admissions and the in-hospital mortality rates before and during the COVID-19 pandemic were evaluated using interrupted time-series analysis. RESULTS: Among the 555,793 adult ED-to-ICU admissions, the number of ED-to-ICU admissions during the pandemic decreased compared to that before the pandemic (step change, 0.916; 95% confidence interval [CI] 0.869-0.966], although the trend did not attain statistical significance (slope change, 0.997; 95% CI 0.991-1.003). The proportion of patients who arrived by emergency medical services, those transferred from other hospitals, and those with injuries declined significantly among the number of ED-to-ICU admissions during the pandemic. The proportion of in-hospital deaths significantly increased during the pandemic (step change, 1.054; 95% CI 1.003-1.108); however, the trend did not attain statistical significance (slope change, 1.001; 95% CI 0.996-1.007). Mortality rates in patients with an ED length of stay of ≥ 6 h until admission to the ICU rose abruptly following the onset of the pandemic (step change, 1.169; 95% CI 1.021-1.339). CONCLUSIONS: The COVID-19 pandemic significantly affected ED-to-ICU admission and in-hospital mortality rates in Korea. This study's findings have important implications for healthcare providers and policymakers planning the management of future outbreaks of infectious diseases. Strategies are needed to address the challenges posed by pandemics and improve the outcomes in critically ill patients.

Exposure to earthquakes and development of ischemic heart disease.

BACKGROUND: The evidence regarding the effect of earthquake exposure on the development of cardiovascular diseases is limited. This study evaluated the association between the 2016 Gyeongju earthquake, which had a magnitude of 5.8, and over 600 subsequent aftershocks occurring within a year in Korea, with the development of ischemic heart disease (IHD) among residents of Gyeongju. METHODS: Ten years (2010-2019) of medical records from a randomly selected cohort of residents (n = 540,858) in Gyeongju and 3 control cities were acquired from the national health insurance service. Employing difference-in-difference and meta-analyses, the risks of IHD development of Gyeongju residents before (reference: Sep 2014 to Aug 2015; period 1: Sep 2015 to Aug 2016) and after (period 2: Sep 2016 to Aug 2017; period 3: Sep 2017 to Aug 2018; period 4: Sep 2018 to Aug 2019) the earthquake were estimated. RESULTS: The monthly average incidence of IHD in Gyeongju was 39.5 persons (per 1,000,000) for reference period and 38.4 persons for period 1. However, the number increased to 58.5 persons in period 2, and 49.8 persons in period 3, following the earthquake. The relative risk (RR) [with a 95% confidence interval] of developing IHD among Gyeongju residents increased by 1.58 times (1.43, 1.73) in period 2, 1.33 times (1.21, 1.46) in period 3, and 1.15 times (1.04, 1.27) in period 4, in comparison to both the control cities and the pre-earthquake reference period. The increase in RR was particularly noticeable among women, adults aged 25-44, and individuals with lower incomes. CONCLUSIONS: The major earthquake in Korea was associated with an increase in the development of IHD among local residents. Individuals exposed to earthquakes may benefit from cardiovascular health surveillance.

Patient's Perspective on Psychiatric Drugs: A Multicenter Survey-Based Study.

OBJECTIVE: We aimed to identify the expectations and preferences for medication and medical decision-making in patients with major psychiatric disorders. METHODS: A survey was conducted among patients with major psychiatric disorders who visited psychiatric outpatient clinics at 15 hospitals between 2016 and 2018 in Korea. The survey consisted of 12 questions about demographic variables and opinions on their expectations for medication, important medical decision-makers, and preferred drug type. The most preferred value in each category in the total population was identified, and differences in the preference ratio of each item among the disease groups were compared. RESULTS: A total of 707 participants were surveyed. In the total population, patients reported high efficacy (44.01%±21.44%) as the main wish for medication, themselves (37.39%±22.57%) and a doctor (35.27%±22.88%) as the main decision makers, and tablet/capsule (36.16%±30.69%) as the preferred type of drug. In the depressive disorders group, the preference ratio of high efficacy was significantly lower, and the preference ratio of a small amount was significantly higher than that of the psychotic disorder and bipolar disorder groups. The preference ratio of a doctor as an important decision maker in the bipolar disorder group was higher compared to the other groups. CONCLUSION: This study revealed the preference for medications and showed differences among patients with psychiatric disorders. Providing personalized medicine that considers a patient's preference for the drug may contribute to the improvement of drug compliance and outcomes.

Excess mortality during the Coronavirus disease pandemic in Korea.

BACKGROUND: Although the ongoing epidemics of Coronavirus disease 2019 (COVID-19) may have affected the mortality trend of the nation, the national level assessment of excess mortality (changes in overall mortality in the entire population) is still scarce in Korea. Therefore, this study evaluated the excess mortality during the COVID-19 pandemic in Korea using the certified mortality data. METHODS: Monthly mortality and population data from January 2013 to June 2022 was obtained from the National Health Insurance Service database and Statistics Korea. A quasi-Poisson interrupted time-series model adjusted for age structure, population, seasonality, and long-term trends was used to estimate the counterfactual projections (expected) of mortality during the COVID-19 pandemic (March 2020 to June 2022). The absolute difference (observed-expected) and ratio (observed / expected) of mortality were calculated. Stratified analysis based on pandemic years (years 2020, 2021, and 2022), sex, and age groups (aged 0-4, 5-19, 20-64, and ≥ 65 years) were conducted. RESULTS: An 8.7% increase in mortality was observed during the COVID-19 pandemic [absolute difference: 61,277 persons; ratio (95% confidence interval (CI)): 1.087 (1.066, 1.107)]. The gap between observed and estimated mortality became wider with continuation of the pandemic [ratio (95% CI), year 2020: 1.021 (1.003, 1.040); year 2021: 1.060 (1.039, 1.080), year 2022: 1.244 (1.219, 1.270)]. Although excess mortality across sex was similar, the adult [aged 20-64, ratio (95% CI): 1.059 (1.043, 1.076)] and elderly [aged 65-, ratio (95% CI): 1.098 (1.062, 1.135)] population showed increased excess mortality during the pandemic. CONCLUSIONS: Despite Korea's successful quarantine policy response, the continued epidemic has led to an excess mortality. The estimated mortality exceeded the number of deaths from COVID-19 infection. Excess mortality should be monitored to estimate the overall impact of the pandemic on a nation.

Effects of municipal smoke-free ordinances on secondhand smoke exposure in the Republic of Korea.

Objective: To reduce premature deaths due to secondhand smoke (SHS) exposure among non-smokers, the Republic of Korea (ROK) adopted changes to the National Health Promotion Act, which allowed local governments to enact municipal ordinances to strengthen their authority to designate smoke-free areas and levy penalty fines. In this study, we examined national trends in SHS exposure after the introduction of these municipal ordinances at the city level in 2010. Methods: We used interrupted time series analysis to assess whether the trends of SHS exposure in the workplace and at home, and the primary cigarette smoking rate changed following the policy adjustment in the national legislation in ROK. Population-standardized data for selected variables were retrieved from a nationally representative survey dataset and used to study the policy action's effectiveness. Results: Following the change in the legislation, SHS exposure in the workplace reversed course from an increasing (18% per year) trend prior to the introduction of these smoke-free ordinances to a decreasing (-10% per year) trend after adoption and enforcement of these laws (ß 2 = 0.18, p-value = 0.07; ß 3 = -0.10, p-value = 0.02). SHS exposure at home (ß 2 = 0.10, p-value = 0.09; ß 3 = -0.03, p-value = 0.14) and the primary cigarette smoking rate (ß 2 = 0.03, p-value = 0.10; ß 3 = 0.008, p-value = 0.15) showed no significant changes in the sampled period. Although analyses stratified by sex showed that the allowance of municipal ordinances resulted in reduced SHS exposure in the workplace for both males and females, they did not affect the primary cigarette smoking rate as much, especially among females. Conclusion: Strengthening the role of local governments by giving them the authority to enact and enforce penalties on SHS exposure violation helped ROK to reduce SHS exposure in the workplace. However, smoking behaviors and related activities seemed to shift to less restrictive areas such as on the streets and in apartment hallways, negating some of the effects due to these ordinances. Future studies should investigate how smoke-free policies beyond public places can further reduce the SHS exposure in ROK.

Experimental study of endurance characteristics of Al-doped HfO2ferroelectric capacitor.

In this work, the endurance characteristics of Al-doped HfO2(HAO)-based metal-ferroelectric-metal (MFM) capacitors (which were annealed at 1000 °C) with various doping concentrations were investigated. The doping concentration was optimized for the high annealing temperature (1000 °C) process. To investigate the impact of cycling pulses on the endurance characteristics of HAO-based MFM capacitor, the rise/fall time (tr/f) and hold time (th) for the cycling pulses were varied. Moreover, by adopting the recoverable fatigue process, the endurance characteristics under repetitive wake-up/fatigue processes were studied. The HAO capacitors achieved the remnant polarization (2Pr) of 23.767µC cm-2at pristine state under the high annealing temperature. Furthermore, it was demonstrated that the endurance characteristics (∼108cycles) of the HAO capacitors were comparable to them of other HfO2-based ferroelectric capacitors. Lastly but not least, it turned out that the amount of oxygen and oxygen vacancies in the HAO thin film was dependent of doping concentrations for the film. The impact of oxygen and oxygen vacancies was quantitatively analyzed, in detail, with TEM, XPS and GIXRD analysis.

Seismic activity and development of mood disorders: Findings from the 2016 Kyungju earthquake.

BACKGROUND: An earthquake with a moment magnitude of 5.8 occurred in Kyungju on 12 September 2016. Although the earthquake was the largest seismic activity in Korean history, there were no direct casualties from the event. This study evaluated whether a moderate-level earthquake is related to acute development of mood disorders in earthquake-exposed residents. MATERIAL AND METHODS: The healthcare information of residents (n = 865,263) living in Kyungju and control cities (Gimpo, Jeonju, Gimhae, and Pohang) over a 10-year period (from 2010 to 2019) was gathered from the national health insurance database. Difference-in-difference analysis was used to compare the daily incidence of mood disorders (manic episode; bipolar affective disorder; depressive episode; recurrent depressive disorder) 20 weeks before (reference: -20 to -11 weeks, period 1: -10 to -1 weeks) and after (period 2: 0-9 weeks, period 3: 10-19 weeks) the earthquake. Subregional analyses based on the distance to the epicenter and stratification analyses by sex, age, and income were conducted. RESULTS: The weekly average incidence rate (/100,000 persons) of mood disorders in Kyungju residents increased from 27.0 (-20 to -11 weeks) and 28.3 (-10 to -1 weeks) persons before the earthquake, to 38.1 persons (0 to 9 weeks) after the earthquake. A significant increase in the risk of developing mood disorders was observed in Kyungju residents during the 0 to 9 weeks after the earthquake when compared to the control cities [relative risk (95 % confidence intervals): vs. Gimpo, 1.40 (1.05, 1.88); vs. Jeonju, 1.45 (1.14, 1.84); vs. Gimhae, 1.48 (1.14, 1.93)]. The increase was more prominent in women, low-income individuals, and those living closer to the epicenter. CONCLUSION: Moderate-level earthquakes without direct casualties may cause mood disorders in residents living in affected areas. Mental health aid programs should be provided to earthquake victims even if the earthquake has caused limited life and property loss.

Association of long-term exposure to PM2.5 and survival following ischemic heart disease.

BACKGROUND: Numerous studies have suggested that long-term exposure to particulate matter ≤2.5 µm (PM2.5) may cause cardiovascular morbidity and mortality. However, susceptibility among those with a history of ischemic heart disease is less clearly understood. We aimed to evaluate whether long-term PM2.5 exposure is related to mortality among patients with ischemic heart disease. METHODS: We followed up 306,418 patients hospitalized with ischemic heart disease in seven major cities in South Korea between 2008 and 2016 using the National Health Insurance Database. We linked the modeled PM2.5 data corresponding to each patient's administrative districts and estimated hazard ratios (HRs) of cause-specific mortality associated with the long-term exposure to PM2.5 in time-varying Cox proportional hazard models after adjusting for individual- and area-level characteristics. We also estimated HRs by sex, age group (65-74 vs. ≥75 years), and household income. RESULTS: Of the patients with ischemic heart disease, mean age at the discharge was 76.8 years, and 105,913 died during a mean follow-up duration of 21.4 months. The HR of all-cause mortality was 1.10 [95% confidence intervals (CI): 1.07, 1.14] per 10 µg/m3 increase in a 12-month moving average PM2.5. The HRs of cardiovascular, stroke, and ischemic heart disease were 1.17 (95% CI: 1.11, 1.24), 1.17 (95% CI: 1.06, 1.30), and 1.25 (95% CI: 1.15, 1.35), respectively. The subgroup analyses showed that participants aged 65-74 years were more susceptible to adverse effects of PM2.5 exposure. We did not observe any differences in the risk by sex and household income. CONCLUSION: Mortality from all-cause and cardiovascular disease following hospitalization due to ischemic heart disease was higher among individuals with greater PM2.5 exposure in seven major cities in South Korea. The result supports the association of long-term exposure to air pollution with poor prognosis among patients with ischemic heart disease.

The Ratio of Second and Fourth Digit Length: A Biomarker for Methamphetamine Dependence?

Objective: The ratio of 2nd and 4th digit length (2D:4D) is considered to be a sexually dimorphic trait. Low 2D:4D is implicated in alcohol dependence and heroin dependence and correlated with psychological traits such as aggression, physical aggression, and sensation. The purpose of this study is to compare the 2D:4D between methamphetamine (METH) dependence and controls and the 2D:4D ratio that is a potential biomarker for METH dependence. Methods: In this study, 40 patients diagnosed with METH dependence in Eulji University Gangnam Eulji Hospital and 50 healthy volunteers were all employees in the same hospital. Images of participants' hands were created using a scanning device. The images contained both the right and left hands; computer software was used to measure the 2D:4D ratio for both hands. We compared the ratios, analyzed by t test, between the METH dependence group and the control group. Results: The mean 2D:4D values were 0.941 (right hand) and 0.943 (left hand) for the patients with METH dependence; in contrast, they were 0.961 (right hand) and 0.961 (left hand) for the control group. These values were significantly smaller than the control in patients' right hands (p = 0.003) and left hands (p = 0.012). Conclusion: Patients with METH dependence had smaller 2D:4D ratios than those in the control group, which is similar to the results from the previous substance use disorder studies. Thus, elevated prenatal testosterone levels during the gonadal period could be related to future METH problems. Furthermore, the 2D:4D ratio is a potential marker for the prediction of METH dependence.

Improved remnant polarization of Zr-doped HfO2 ferroelectric film by CF4/O2 plasma passivation.

In this work, the impact of fluorine (CF4) and oxygen (O2) plasma passivation on HfZrOx (HZO) based ferroelectric capacitor was investigated. By the fluorine passivation, the surface trap density and oxygen vacancies in the HZO-based Metal-ferroelectric-insulator-semiconductor (MFIS) capacitors were suppressed, resulting in the increased pristine remnant polarization (2Pr). The pristine value (2Pr) of baseline samples annealed at 500 °C and 600 °C were 11.4 µC/cm2 and 24.4 µC/cm2, respectively. However, with the F-passivation, the 2Pr values were increased to 30.8 µC/cm2 and 48.2 µC/cm2 for 500 °C and 600 °C, respectively. The amount of surface defects and oxygen vacancies are quantitatively confirmed by the conductance method and XPS analysis. However, due to the incorporation of fluorine atoms into the ferroelectric-insulator films, undesirable degradation on endurance characteristics were observed.

Vertical Gate-All-Around Device Architecture to Improve the Device Performance for Sub-5-nm Technology.

In this work, we propose a vertical gate-all-around device architecture (GAA-FinFET) with the aim of simultaneously improving device performance as well as addressing the short channel effect (SCE). The GAA-FinFET was built using the technology computer-aided design (TCAD) simulation tool, and then, its electrical characteristics were quantitatively evaluated. The electrical characteristics of the GAA-FinFET were compared to those of conventional FinFET and nano-sheet FET (NSFET) at 7 nm or 5 nm nodes. When comparing the GAA-FinFET against the FinFET, it achieved not only better SCE characteristics, but also higher on-state drive current due to its gate-all-around device structure. This helps to improve the ratio of effective drive current to off-state leakage current (i.e., Ieff/Ioff) by ~30%, resulting in an improvement in DC device performance by ~10%. When comparing the GAA-FinFET against the NSFET, it exhibited SCE characteristics that were comparable or superior thanks to its improved sub-channel leakage suppression. It turned out that the proposed GAA-FinFET (compared to conventional FinFET at the 7 nm or 5 nm nodes, or even beyond) is an attractive option for improving device performance in terms of SCE and series resistance. Furthermore, it is expected that the device structure of GAA-FinFET is very similar to that of conventional FinFET, resulting in further improvement to its electrical characteristics as a result of its gate-all-around device structure without significant modification with respect to the processing steps for conventional FinFET.

Urinary phthalate metabolites and anemia: Findings from the Korean National Environmental Health Survey (2015-2017).

BACKGROUND: Several animal studies have suggested an association between phthalate exposure and decreased hemoglobin levels. To address the lack of epidemiological evidence, we evaluated the association between urinary phthalate metabolite concentrations and hematologic indices by using nationally representative data from Korea. METHODS: Data from 3722 adults included in the third stage (2015-2017) of the Korean National Environmental Health Survey (KONEHS) were used. The association between various urinary phthalate metabolites and hematologic indices (hemoglobin, hematocrit, mean corpuscular volume [MCV], and red blood cell [RBC], white blood cell [WBC], and platelet counts) was evaluated using linear regression analysis adjusted for potential confounders. Sex-stratified analysis was performed. RESULTS: All urinary phthalate metabolites were negatively associated with hemoglobin levels. A two-fold increase in urinary mono-(2-ethyl-5-carboxy-pentyl) phthalate (MECPP), mono-carboxyoctyl phthalate (MCOP), mono-carboxyonyl phthalate (MCNP), and mono-(3-carboxypropyl) phthalate (MCPP) levels was associated with a -0.099 g/dL (95% confidence interval (CI), -0.137 to -0.060), -0.116 g/dL (95% CI, -0.156 to -0.076), -0.111 g/dL (95% CI, -0.154 to -0.068), and -0.144 g/dL (95% CI, -0.198 to -0.089) change in hemoglobin levels, respectively. The RBC count and MCV showed negative and positive associations, respectively, with urinary phthalate metabolite concentrations. WBC counts were positively associated with MECPP, MCOP, MCNP, and MCPP levels, whereas the platelet count showed no association with urinary phthalate metabolites. CONCLUSIONS: Urinary phthalate metabolite concentration showed a negative association with hemoglobin level. Since this was a cross-sectional study, further longitudinal and experimental studies are needed to identify a clear causal linkage and the pathological mechanism underlying phthalate exposure and anemia.

Impact of Chamber/Annealing Temperature on the Endurance Characteristic of Zr:HfO2 Ferroelectric Capacitor.

The endurance characteristic of Zr-doped HfO2 (HZO)-based metal-ferroelectric-metal (MFM) capacitors fabricated under various deposition/annealing temperatures in the atomic layer deposition (ALD) process was investigated. The chamber temperature in the ALD process was set to 120 °C, 200 °C, or 250 °C, and the annealing temperature was set to 400 °C, 500 °C, 600 °C, or 700 °C. For the given annealing temperature of 700 °C, the remnant polarization (2Pr) was 17.21 µC/cm2, 26.37 µC/cm2, and 31.8 µC/cm2 at the chamber temperatures of 120 °C, 200 °C, and 250 °C, respectively. For the given/identical annealing temperature, the largest remnant polarization (Pr) was achieved when using the chamber temperature of 250 °C. At a higher annealing temperature, the grain size in the HZO layer becomes smaller, and thereby, it enables to boost up Pr. It was observed that the endurance characteristics for the capacitors fabricated under various annealing/chamber temperatures were quite different. The different endurance characteristics are due to the oxygen and oxygen vacancies in ferroelectric films, which affects the wakeup/fatigue behaviors. However, in common, all the capacitors showed no breakdown for an externally applied pulse (up to 108 cycles of the pulse).

Changes in mortality rate of the general population during the COVID-19 pandemic: an interrupted time series study in Korea.

BACKGROUND: Unlike other countries, South Korea did not implement a large-scale lockdown or closure of businesses to manage the coronavirus disease 2019 (COVID-19) pandemic, but relied on changes in population behaviours and early isolation and treatment of patients. It is important to evaluate the effectiveness of such alternative strategies on the mortality of the general population. METHODS: Mortality and monthly population data from 2013 to 2020 were obtained. A quasi-Poisson regression model adjusting for age structure, seasonality and time was used to evaluate whether underlying trends for monthly mortality rate have changed with the pandemic. Stratification analyses based on sex and location of deaths (inside vs outside of medical facilities) were conducted. RESULTS: The risk estimates showed no changes in non-accidental mortality during the COVID-19 pandemic [relative risk (RR) (95% confidence interval, 95% CI), slope change: 1.00 (1.00, 1.01), step change: 0.99 (0.97, 1.01)] compared with those before the pandemic. In cause-specific analysis, there was an abrupt and sustained decrease in the mortality rate of respiratory diseases [RR (95% CI), step change: 0.81 (0.77, 0.84)]. In the analysis of deaths by location, an increase in non-accidental mortality [RR (95% CI), slope change: 1.01 (1.01, 1.02), step change: 1.16 (1.11, 1.22)] and several cause-specific mortalities was observed outside of medical facilities. CONCLUSIONS: The non-accidental mortality rate in South Korea for the first year of the pandemic followed the historical trends. However, there was a decrease in mortality associated with respiratory diseases, and an increase in mortality occurring outside of medical facilities. The findings may be attributed to changes in public behaviours, and availability of medical resources during the pandemic.

Particulate respirator use and blood pressure: A systematic review and meta-analysis.

People use a particulate respirator in order to reduce exposure to ambient fine particulate matter (PM2.5). Acute exposure to PM2.5 is known to increase blood pressure. However, systematic reviews or meta-analyses on blood pressure-related benefits of using a particulate respirator is lacking. Therefore, we reviewed randomized crossover intervention studies on blood pressure-related effects of particulate matter respirator use. We conducted a literature review of articles found on Embase, Medline, and Cochrane library on August 31, 2020. The study outcomes were systolic and diastolic blood pressure and mean arterial pressure. A random-effect model was used in the meta-analysis. Subgroup analyses, based on age (adult < 60 years, elderly ≥ 60 years), personal PM2.5 exposure levels (High: ≥ 25 µg/m3, Low: < 25 µg/m3), and types of monitoring methods (ambulatory and resting blood pressure) were conducted. We identified 297 references, and seven studies were included in our systematic review. None of the studies used a sham respirator as control and complete allocation concealment and blinding were impossible. The use of a particulate respirator was associated with a -1.23 mmHg (95% confidence interval (CI): -2.53, 0.07) change in systolic blood pressure and a -1.57 mmHg (95% CI: -3.85, 0.71) change in mean arterial pressure. There were significant heterogeneities and possibilities for publication bias. The subgroup analyses revealed that studies involving elderly individuals, those conducted in high PM2.5 personal exposure, and those in which resting blood pressure was monitored demonstrated a larger decrease in blood pressure resulting from respirator use. Further intervention studies with a large sample size and subjects with diverse characteristics and different personal PM2.5 levels may add the evidence to current literature.

Short-term exposure to air pollution and hospital admission for heart failure among older adults in metropolitan cities: a time-series study.

PURPOSE: We aimed to investigate the association between air pollution concentration levels and hospital admissions for heart failure (HF) among older adults in metropolitan cities in South Korea. METHODS: We used hospital admission data of 1.8 million older adults in seven metropolitan cities from 2008 to 2016, derived from the National Health Insurance Service of South Korea. Daily HF admission data were linked to air pollutants concentrations for the respective dates, including particulate matter less than 2.5 µm in size (PM2.5), 10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone. We estimated the association between air pollutants and daily HF admissions using quasi-Poisson generalized additive models for each city. RESULTS: During the study period, 142,490 hospital admissions for HF were noted. Increases of 10 µg/m3 of PM2.5 and PM10, and 10 ppb of SO2, NO2, and CO were associated with an increased risk of HF admission by 0.93% ([95% confidence intervals 0.51-1.36], 0.55% [0.31-0.80], 6.04% [2.15-10.08], 1.10% [0.38-1.82], and 0.05% [0.01-0.09]), respectively, on the same day. Increases in mean exposure to PM2.5, PM10, and SO2 for 8 days from the concurrent day were also significantly associated with HF admissions. During the warm season, the risk of HF admissions increased shortly after an increase in PM2.5, whereas prolonged effects were observed during the cold season. CONCLUSION: Our study suggests the adverse effects of air pollution on HF. Moreover, the evidence of seasonality may help tailor protection guidelines for older adults.

Particulate air pollution and survival after stroke in older adults: A retrospective cohort study in Korea.

Although many studies have evaluated the effects of ambient particulate matter with diameters of less than 2.5 µm (PM2.5) on stroke mortality in the general population, little is known about the mortality effects of PM2.5 in post-stroke populations. Therefore, a retrospective cohort was constructed using information from the health insurance database to evaluate whether exposure to PM2.5 is associated with increased mortality in aged stroke survivors residing in seven Korean metropolitan cities. A total of 45,513 older adults (≥65 years) who visited emergency rooms due to stroke and who were discharged alive between 2008 and 2016 were followed up. By using district-level modeled PM2.5 concentrations and a time-varying Cox proportional hazard model, associations between 1-month and 2-month moving average PM2.5 exposures and mortality in stroke survivors were evaluated. The annual average concentration of PM2.5 was 27.9 µg/m3 in the seven metropolitan cities, and 14,880 subjects died during the follow-up period. A 10 µg/m3 increase in the 1-month and 2-month moving average PM2.5 exposures was associated with mortality hazard ratios of 1.07 (95% confidence interval: 1.05, 1.09) and 1.06 (95% confidence interval: 1.03, 1.08), respectively. The effects of PM2.5 were similar across types of stroke (ischemic and hemorrhagic), age groups (65-74, 75-84, and ≥85), and income groups (low and high) but were greater in women than in men. This study highlights the adverse health effects of ambient PM2.5 in post-stroke populations. Active avoidance behaviors against PM2.5 are recommended for aged stroke survivors.

Long-term exposure to fine particulate matter and incident asthma among elderly adults.

RATIONALE: Although an association of fine particulate matter (PM2.5) with asthma incidence has been assumed, there is insufficient evidence regarding the effect of long-term exposure to PM2.5 on incident asthma among elderly adults. OBJECTIVES: This study aimed to investigate an association between long-term exposure to PM2.5 and incident asthma among elderly adults in South Korea. METHODS: Adults ≥65 years of age (n = 1,220,645) who did not visit hospitals for asthma during a washout period (between 2008 and 2010) were followed up until 2016 using data from the National Health Insurance System in South Korea. Incident asthma was defined as the number of patients with a primary diagnostic code of asthma who visited hospitals more than twice. We linked the health data with district-level PM2.5 concentrations and estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for incident asthma after adjusting for potential confounders in time-varying Cox proportional hazard models. MEASUREMENTS AND MAIN RESULTS: Over 5,942,256 person-years, 54,522 patients developed asthma, with an incidence of 9.2 cases/1000 person-years. A 10 µg/m3 increase in the 36-month mean PM2.5 concentration was significantly associated with a 9% increase in incident asthma (HR = 1.09, 95% CI: 1.04-1.14). This association was found to be robust for different definitions of incident asthma and washout periods. CONCLUSION: Long-term exposure to PM2.5 was associated with the incidence of asthma in elderly adults. This finding provides evidence of an association between PM2.5 and adult-onset asthma.