Time-stratified Case-crossover Study Research Articles

Short-term effects of air pollutants on hospitalization for childhood respiratory diseases in Suzhou City: a time-stratified case-crossover study

BackgroundShort-term exposure to air pollution has been demonstrated in previous studies to correlate with respiratory disease (RD) in children. Due to regional heterogeneity, our objective was to explore the correlation between short-term exposure to ambient air pollution and hospital admissions for respiratory ailments in children in Suzhou City from January 1, 2017, to December 31, 2022, alongside assessing the influence of the COVID-19 pandemic on this relationship.MethodsWe collected data on air pollutant levels and hospital admissions for childhood respiratory disease (RD) in Suzhou, China, from 2017 to 2022. We utilized a time-stratified case-crossover design along with a conditional logistic regression model to assess the short-term impacts of air pollutants on RD in children through stratified analysis and sensitivity analysis.ResultsA total of 13,408 children with respiratory diseases were included in the study. The findings revealed significant associations between hospitalization for respiratory diseases in children and exposure to PM2.5, PM10, SO2, NO2, and CO. The maximum effect values (95%CI, best lag days) for each 10 µg/m3 increase in the concentrations of PM2.5, PM10, SO2, and NO2 were as follows: 1.017 (1.003–1.031, lag0-2), 1.015 (1.004–1.026, lag0-2), 1.117 (1.001–1.247, lag0-1), and 1.036 (1.009–1.064, lag0-7). Additionally, the maximum effect value (95%CI, best lag days) for each 1 mg/m3 increase in CO concentration was found to be 1.267 1.017–1.579, lag0-7). Stratified analysis indicated that sex, season of admission, and stage of admission did not modify these correlations significantly; however, differential effects on various age groups and sexes were primarily observed among school-age and older children as well as boys.ConclusionsThe short-term exposure to PM2.5, PM10, SO2, NO2, and CO in Suzhou, China, exhibited a positive correlation with RD hospitalization. Prior to the COVID-19 pandemic, the adverse impacts of air pollutants on hospitalizations for childhood respiratory disease were mitigated compared to the period following the pandemic. Local governments should continue promoting decisions and measures for air pollution prevention and control to reduce further pollutant concentration, which is crucial for public health in reducing the burden of childhood respiratory diseases.

Association of short-term exposure to ambient air pollution and temperature with bronchiectasis mortality: a nationwide time-stratified case-crossover study

Ambient pollution and non-optimal temperature are major risk factors for respiratory health. However, the relationships between short-term exposure to these factors and bronchiectasis mortality remain unknown. A nationwide, time-stratified case-crossover study across Mainland China was conducted from 2013 to 2019. Records of bronchiectasis deaths were extracted from the National Death Registration Reporting Information System. Daily concentrations of fine particulate matter (PM2.5), coarse particulate matter (PM2.5-10), nitrogen dioxide (NO2), ozone (O3), and daily temperature were obtained from high-resolution prediction models. We utilized conditional logistic regression model and distributed lag nonlinear model to explore the associations of these exposures with bronchiectasis mortality. We included a total of 19,320 bronchiectasis deaths. Air pollutant was associated with bronchiectasis mortality within the first 3 days after exposure and the exposure-response relationships were almost linear. An interquartile range increase in PM2.5, PM2.5-10, and O3 was associated with increments of 3.18%, 4.14%, and 4.36% in bronchiectasis mortality at lag 02 d, respectively. Additionally, lower temperature was associated with higher odds of bronchiectasis mortality. Compared to referent temperature (23.6°C), the odds ratio for bronchiectasis mortality associated with extremely low temperature (P1:-13.4°C) was 1.54 (95% CI: 1.05, 2.25). This national study provides compelling evidence, and highlights the necessity and importance of reducing air pollution exposures and keeping warm for susceptible populations. National Natural Science Foundation of China (81925001; 82330070); Innovation Program of Shanghai Municipal Education Commission (202101070007-E00097); Program of Shanghai Municipal Science and Technology Commission (21DZ2201800); Program of Shanghai Shenkang Development Center (SHDC12023110); and Major Project of National Health Commission of China.

Non-fatal Injury burden attributed to night-time temperature during 1990s-2010s in China

The night-time temperature-related injury risks and burdens were unclear. Using 11,512,467 non-fatal injury cases in 243 surveillance hospitals across China from 2006-2021, we estimated the associations between daytime or night-time temperature and injury by a time-stratified case-crossover study, and compared their injury burden during 1990s–2010s. We found the excess risk (ER) for per 1°C rise in night-time temperature (ER = 1.21%, 95%CI:1.03%,1.39%) was greater than that in daytime (ER = 0.86%, 95%CI:0.72%,1.00%). Compared with the 1980s, the attributable fractions (AFs) for daytime and night-time temperature change during the 1990s–2010s were 0.59% (95%eCI:0.54%,0.67%) and 0.73% (95%eCI:0.69%,0.77%), respectively. Spatially, the higher AFs of night-time temperature were more widely distributed than daytime temperature. The non-fatal injury risk attributed to night-time temperature was stronger than daytime temperature, and increased night-time temperatures posed a heavier injury burden compared with daytime temperature in China. Our findings indicate that high night-time temperature is an important injury risk in the context of climate change.

Effects of fine particulate matter from wildfire and non-wildfire sources on emergency-department visits in people who were housed and unhoused in San Diego County (CA, USA) during 2012–20: a time-stratified case–crossover study

Being unhoused can increase vulnerability to adverse health effects due to air pollution. We aimed to quantify changes in emergency-department visits during and after exposure to wildfire-specific and non-wildfire particulate matter 2·5 μm or less in diameter (PM2·5) in San Diego County (CA, USA) in people who were both unhoused and housed. For this time-stratified case-crossover study, we used data on exposure to wildfire-specific PM2·5 in California and individual-level data for people admitted to the emergency departments of two hospitals (UC San Diego Health emergency departments at La Jolla and Hillcrest, San Diego) in San Diego County between July 1, 2012, and Dec 31, 2020. People with a postcode outside of San Diego County were excluded. Demographic information was age group, race or ethnicity, and transport to the emergency department. Wildfire-specific PM2·5 concentration at the postcode level was previously estimated using an ensemble model that combined multiple machine-learning algorithms and explanatory variables obtained via data on 24-h mean PM2·5 concentrations from the US Environmental Protection Agency Air Quality System. Conditional logistic regression models were applied, adjusting for specific humidity, wind velocity, and maximum temperature extracted from the US Gridded Surface Meteorological Dataset. Housing status was established by registration staff or triage nurses on arrival at the emergency department. For people who were unhoused, exposure was defined based on the weighted mean PM2·5 concentration at the city level proportional to the number of people who were unhoused in each specific city across urban centres in San Diego County. For people who were housed, we used residence postcode to measure exposure. We assessed the association between PM2·5 from wildfire and non-wildfire sources and emergency-department visits in people who were housed and unhoused. There were 587 562 emergency-department visits at the two hospitals, 76 407 (13·0%) of which were by people who were unhoused. People who were housed had a higher exposure to overall PM2·5 (24-h mean over the study period of 9·904 mg/m3, SD 3·445) and non-wildfire PM2·5 (9·663, 2·977) than people who were unhoused (9·863, 3·221; 9·557, 2·599). However, people who were unhoused had a higher exposure to wildfire-specific PM2·5 (0·305, 1·797) than people who were housed (0·240, 1·690). Overall PM2·5 exposure was associated with increased odds of emergency-department visits for both people who were housed (odds ratio 1·003, 95% CI 1·001-1·004 per 1 μg/m3 PM2·5 for 0-3 days after exposure) and people who were unhoused (1·004, 1·000-1·008 for 0-3 days after exposure). We found that non-wildfire PM2·5 was associated with emergency-department visits among people who were housed (1·003, 1·002-1·005 for 0-3 days after exposure) and wildfire-specific PM2·5 was associated with emergency-department visits in people who were unhoused (1·006, 1·001-1·011 for 0-3 days after exposure). People who were unhoused in San Diego County were more likely to visit emergency departments after exposure to increased wildfire-specific PM2·5. As the intensity and frequency of wildfires increase, understanding risk factors for vulnerable populations, such as people who are unhoused, is crucial to develop effective adaptation strategies. US National Institutes of Health, National Institute on Aging.

Increased Emergency Department Medical Imaging: Association with Short-Term Exposures to Ambient Heat and Particulate Air Pollution.

Background Climate change adversely affects human health, resulting in higher demand for health care services. However, the impact of climate-related environmental exposures on medical imaging utilization is currently unknown. Purpose To determine associations of short-term exposures to ambient heat and particulate air pollution with utilization of emergency department medical imaging. Materials and Methods In this retrospective time-stratified case-crossover study, daily imaging utilization counts from four emergency departments were linked to local daily environmental data-including fine particulate matter with 2.5-µm or smaller aerodynamic diameter (PM2.5) and ambient temperature-over 10 years (January 2013 to December 2022). Conditional Poisson regression models were used to evaluate the associations between daily imaging utilization and environmental exposures on the same day and each of the 7 days preceding imaging, lag days 0-7, controlling for day of the week, month, and year. Moving averages of mean daily PM2.5 and temperature were calculated to account for lagged exposure effects. Imaging counts were also stratified by modality (CT, radiography, US, and MRI). Results In an analysis of 1 666 420 emergency department imaging studies, a rise of 10 °C in the 2-day moving average of mean daily temperature and a rise of 10 μg/m3 in the 3-day moving average of mean daily PM2.5 were associated with overall imaging utilization increases of 5.1% (incidence rate ratio [IRR], 1.051; 95% CI: 1.045, 1.056) and 4.0% (IRR, 1.040; 95% CI: 1.035, 1.046), respectively. Heat exposure days (mean temperature >20 °C) and air pollution exposure days (mean PM2.5 >12 μg/m3) were associated with same-day excess absolute risk of 5.5 and 6.4 imaging studies per 1 million people at risk per day, respectively. Heat exposure days and air pollution exposure days were associated with increased utilization of radiography (excess relative risk, 2.7% [P < .001] and 2.1% [P < .001], respectively) and CT (excess relative risk, 2.0% [P = .001] and 2.7% [P < .001]) but not US (P = .14 and P = .14) or MRI (P = .70 and P = .65). Conclusion Short-term exposures to ambient heat and particulate air pollution were associated with increased utilization of radiography and CT but not US or MRI. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Vosshenrich in this issue.

Association between heat exposure and Kawasaki disease: A time-stratified case-crossover study

Nationwide studies investigating the association between daily mean temperature and Kawasaki disease are lacking. This study aimed to examine the association between ambient temperature and Kawasaki disease by utilizing daily data from nationwide administrative claims databases. The daily number of Kawasaki disease patients younger than 15 years old, who were hospitalized from 2011 to 2022, was extracted from the nationwide administrative claims database of hospitalizations in Japan. Daily mean temperature data and relative humidity data were obtained from the Japan Meteorological Agency. Since the exposure of interest includes heat, hospitalizations during the five warmest months (May through September) were used for analysis. A time-stratified case-crossover study with conditional quasi-Poisson regression analysis was used to estimate the relative risk (RR) of weather exposure for Kawasaki disease hospitalization with a lag of 0–5 days by prefecture. Relative humidity was included in the model simultaneously to control for its potential confounding effect. Random-effects meta-analysis was used to estimate pooled RRs. There was a total of 48,784 cases of Kawasaki disease hospitalization during the study period, of which 87.9% were under 5 years of age. Exposure to high daily mean temperatures was associated with an increased risk of hospitalization for Kawasaki disease. Specifically, exposure to extreme high daily mean temperatures (99th percentile high temperature) was associated with higher risk of hospitalization by 33% (RR 1.33, 95% confidence interval (CI):1.08, 1.65). Similar results were obtained from sensitivity analysis. Future research should elucidate the mechanisms by which high temperature is associated with hospitalization for Kawasaki disease.

Comorbidities, Tobacco Exposure, and Geography: Added Risk Factors of Heat and Cold Wave Related Mortality among United States Veterans with COPD.

Understanding the health risks associated with extreme weather events is needed to inform policies to protect vulnerable populations. To address this need, we estimated heat and cold wave related mortality risks in a cohort of veteran patients with chronic obstructive pulmonary disease (COPD) and explored disparities among strata of comorbidities, tobacco exposure, and urbanicity. We designed a time stratified case-crossover study among deceased patients with COPD between 2016 to 2021 in the Veterans Health Administration system. Distributed lag models with conditional logistic regression estimated incidence rate ratios (IRR) of heat and cold wave associated mortality risk from lag days 0 to 3 for heatwaves and 0 to 7 for cold waves. Attributable risks (AR) per 100,000 patients were also calculated. Of the 377,545 deceased patients with COPD, the largest heatwave related mortality risk was in patients with COPD and asthma, AR: 14,016 (95% CI: -326, 30,706) across lag days 0 to 3. The largest cold wave related mortality burden was in patients with COPD with no other reported comorbidities, AR: 1,704 (95% CI: 759, 2,686) across lag days 0 to 7. Patients residing in urban settings had the greatest heatwave, AR: 1,062 (95% CI: (576, 1,559), and cold wave AR: 1,261 (95% CI: 440, 2,105) related mortality risk (across lag days 0 to 1 and 0 to 7 respectively). There were no differences in mortality risk by tobacco exposure. Our findings show individuals with COPD are susceptible to heat and cold waves. This information can inform clinical practice and public health policy about the mortality risk vulnerable populations experience with respect to extreme weather conditions. Furthermore, our results may be used in the development and refinement of future extreme weather warning systems designed for public health purposes.

Ambient Air Pollution and Hospitalizations for Schizophrenia in China

Schizophrenia episodes may be triggered by short-term environmental stimuli. Short-term increases in ambient air pollution levels may elevate the risk of schizophrenia episodes, yet few epidemiologic studies have examined this association. To investigate whether short-term increases in air pollution levels are associated with an additional risk of schizophrenia episodes, independent of absolute air pollution concentrations, and whether sustained increases in air pollution levels for several days are associated with more pronounced risks of schizophrenia episodes. This nationwide, population-based, time-stratified case-crossover study was performed based on hospitalization records for schizophrenia across 295 administrative divisions of prefecture-level or above cities in China. Records were extracted from 2 major health insurance systems from January 1, 2013, to December 31, 2017. Thirty-six cities with a small number of schizophrenia hospitalizations (n < 50) were excluded. Data analysis for this study was performed from January to March 2024. Daily absolute concentrations of fine particulate matter (PM2.5), inhalable particulate matter (PM10), nitrogen dioxide, sulfur dioxide, ozone, and carbon monoxide were collected. Air pollution increases between neighboring days (APINs) were generated as the differences in absolute air pollution concentrations on the current day minus that on the previous day. Sustained increases (APIN ≥5 μg/m3 for PM2.5 and PM10, APIN ≥1 μg/m3 for nitrogen dioxide and sulfur dioxide, and APIN ≥0.05 mg/m3 for carbon monoxide) lasting for 1 or more to 4 or more days were defined for different air pollutants. Patients with schizophrenia episodes were identified by principal discharge diagnoses of schizophrenia. A conditional logistic regression model was used to capture the associations of absolute concentrations, APINs, and sustained increase events for different air pollutants with risks of schizophrenia hospitalizations. The study included 817 296 hospitalization records for schizophrenia across 259 Chinese cities (30.6% aged 0-39 years, 56.4% aged 40-64 years, and 13.0% aged ≥65 years; 55.04% male). After adjusting for the absolute concentrations of respective air pollutants, per-IQR increases in 6-day moving average (lag0-5) APINs of PM2.5, PM10, nitrogen dioxide, sulfur dioxide, and carbon monoxide were associated with increases of 2.37% (95% CI, 0.88%-3.88%), 2.95% (95% CI, 1.46%-4.47%), 4.61% (95% CI, 2.93%-6.32%), 2.16% (95% CI, 0.59%-3.76%), and 2.02% (95% CI, 0.39%-3.68%) in schizophrenia hospitalizations, respectively. Greater risks of schizophrenia hospitalizations were associated with sustained increases in air pollutants lasting for longer durations up to 4 or more days. This case-crossover study of the association between ambient air pollution increases and schizophrenia hospitalizations provides novel evidence that short-term increases in ambient air pollution levels were positively associated with an elevated risk of schizophrenia episodes. Future schizophrenia prevention practices should pay additional attention to APINs, especially sustained increases in air pollution levels for longer durations, besides the absolute air pollution concentrations.

Vulnerability to heat-related mortality and the effect of prevention measures: a time-stratified case-crossover study in Switzerland.

Swiss climate scenarios predict increases in the frequency and intensity of extreme heat episodes in the future. For the effective prevention of heat-related mortality, several aspects of the population's vulnerability to heat must be understood on a local level. A nationwide analysis of individual death records was conducted, enabling a more comprehensive understanding than typical heat studies based on aggregated data. A total of 320,306 individual death records from the Swiss National Cohort with precise address information during the warm season (May to September) from 2003-2016 were linked to indoor and outdoor high-resolution daily temperature estimates. A time-stratified case-crossover study combined with distributed lag non-linear models was then performed to assess the temperature-mortality associations for various causes of death and to estimate the potential effect modification of individual characteristics. Additionally, it was explored whether the effect of extreme heat changed over time in regions with and without cantonal heat-health action plans (HHAPs). Using the temperature with the lowest cause-specific mortality risk (minimum mortality temperature) as the reference temperature, extreme heat (defined as ambient daily maximum temperature reaching 33 °C) was associated with a strong increase in all-cause mortality (odds ratio (OR): 1.21, 95% CI: 1.17-1.25) and disease-specific mortality from Alzheimer's disease and dementia (OR: 1.67, 95% CI: 1.48-1.88), COPD (OR: 1.37, 95% CI: 1.12-1.67), diabetes (OR: 1.34, 95% CI: 1.06-1.70), and myocardial infarction (OR: 1.26, 95% CI: 1.10-1.44). Indoor temperatures above 24 °C were found to be critical for mortality. The population most vulnerable to heat included older adults (≥75 years), unmarried individuals, people with a low education level, older women with low neighbourhood socioeconomic position, and men under 75 years old with low socioeconomic position. Overall, the risk of heat-related all-cause mortality in 2009-2016 was lower than that in 2003-2008. The decrease was significantly stronger in the region where cantonal HHAPs were implemented. This study provides important information for planning targeted and effective measures to reduce heat-related health risks in Switzerland. It demonstrates that HHAPs contribute to reducing heat-related mortality, although they may not reach the high-risk population of individuals with low socioeconomic position. Future prevention efforts should also target the less privileged population, including people younger than 75 years.

Short-term exposure to nitrogen dioxide and cardiopulmonary mortality among the oldest-old people: A nationwide time-stratified case-crossover study in China

Short-term exposure to nitrogen dioxide and cardiopulmonary mortality among the oldest-old people: A nationwide time-stratified case-crossover study in China

Summer temperature and emergency room visits due to urinary tract infection in South Korea: a national time-stratified case-crossover study

BackgroundAlthough urinary tract infection (UTI) is a common and severe public health concern, and there are clear biological mechanisms between UTI and hot temperatures, few studies have addressed the association between hot temperatures and UTI.MethodsWe designed a time-stratified case-crossover study using a population-representative sample cohort based on the National Health Insurance System (NHIS) in South Korea. We obtained all NHIS-based hospital admissions through the emergency room (ER) due to UTI (using a primary diagnostic code) from 2006 to 2019. We assigned satellite-based reanalyzed daily summer (June to September) average temperatures as exposures, based on residential districts of beneficiaries (248 districts in South Korea). The conditional logistic regression was performed to evaluate the association between summer temperature and UTI outcome.ResultsA total of 4,436 ER visits due to UTI were observed during the summer between 2006 and 2019 among 1,131,714 NHIS beneficiaries. For 20% increase in summer temperatures (0–2 lag days), the odd ratio (OR) was 1.06 (95% CI: 1.02–1.10) in the total population, and the association was more prominent in the elderly (people aged 65 y or older; OR:1.11, 95% CI: 1.05–1.17), females (OR: 1.12, 95% CI: 1.05–1.19), and people with diabetes history (OR: 1.14, 95% CI: 1.07–1.23). The effect modification by household income was different in the total and elderly populations. Furthermore, the association between summer temperature and UTI increased during the study period in the total population.ConclusionsOur results are consistent with the hypothesis that higher summer temperatures increase the risk of severe UTIs, and the risk might be different by sub-populations.

Nationwide Analysis of the Relationship Between Low Ambient Temperature and Acute Aortic Dissection-related Hospitalizations.

Acute aortic dissection (AAD) is a life-threatening cardiovascular emergency. Therefore, identifying modifiable risk factors for AAD is of great public health significance. An association between ambient temperature (AT) and AAD has been reported; however, not all findings have been elucidated. This study examined the association between AAD-related hospitalization and AT using data from the Japanese Registry of All Cardiac and Vascular Diseases Diagnostic Procedure Combination (JROAD-DPC), which is a nationwide claims-based database. This nationwide time-stratified case-crossover study evaluated data of hospitalized patients with AAD from 1,119 certified hospitals between 2012 and 2020 using the JROAD-DPC database. Conditional logistic regression and distributed lag non-linear models were used to investigate the association between average daily temperature and AAD-related hospitalization. Among the 96,812 cases analyzed. The exposure-response curve between AT and AAD-related hospitalization showed an increase in the odds ratio for lower temperatures, with a peak at timed -10°C (odds ratio: 2.28, 95% confidence interval: 1.92-2.71, compared with that at 20°C). The effects of temperature on lag days 0 and 1 were also significant.Stratified analyses showed a greater association between AT and AAD-related hospitalization for the following variables: older age (≥75 years), female sex (44.4%, the mean age ± SD was 76 ± 12 years), low body mass index (<22), winter season, and warmer regions. Low AT is associated with an increased risk of AAD-related hospitalization. Several susceptible groups are affected by cold temperatures and have a higher risk of hospitalization.

Nighttime Heat and Road Mortality: A Time-stratified Case-crossover Study

Nighttime Heat and Road Mortality: A Time-stratified Case-crossover Study

Acute impact of air pollution on infant mortality in the San Joaquin Valley, California: A time-stratified case-crossover study

Acute impact of air pollution on infant mortality in the San Joaquin Valley, California: A time-stratified case-crossover study

Short-term exposure to ambient fine particulate matter constituents and myocardial infarction mortality

Short-term ambient fine particulate matter (PM2.5) exposure has been related to an increased risk of myocardial infarction (MI) death, but which PM2.5 constituents are associated with MI death and to what extent remain unclear. We aimed to explore the associations of short-term exposure to PM2.5 constituents with MI death and evaluate excess mortality. We conducted a time-stratified case-crossover study on 237,492 MI decedents in Jiangsu province, China during 2015–2021. Utilizing a validated PM2.5 constituents grid dataset at 1 km spatial resolution, we estimated black carbon (BC), organic carbon (OC), sulfate (SO42−), nitrate (NO3−), ammonium (NH4+), and chloride (Cl−) exposure by extracting daily concentrations grounding on the home address of each subject. We employed conditional logistic regression models to evaluate the exposure-response relationship between PM2.5 constituents and MI death. Overall, per interquartile range (IQR) increase of BC (lag 06-day; IQR: 1.75 μg/m3) and SO42− (lag 04-day; IQR: 5.06 μg/m3) exposures were significantly associated with a 3.91% and 2.94% increase in odds of MI death, respectively, and no significant departure from linearity was identified in the exposure-response curves for BC and SO42−. If BC and SO42− exposures were reduced to theoretical minimal risk exposure concentration (0.89 μg/m3 and 1.51 μg/m3), an estimate of 4.55% and 4.80% MI deaths would be avoided, respectively. We did not find robust associations of OC, NO3−, NH4+, and Cl− exposures with MI death. Individuals aged ≥80 years were more vulnerable to PM2.5 constituent exposures in MI death (p for difference <0.05). In conclusion, short-term exposure to PM2.5-bound BC and SO42− was significantly associated with increased odds of MI death and resulted in extensive excess mortality, notably in older adults. Our findings emphasized the necessity of reducing toxic PM2.5 constituent exposures to prevent deaths from MI and warranted further studies on the relative contribution of specific constituents.

Short-term exposure to gaseous ambient pollution and hospital admissions for mental health among children and adolescents: A time-stratified case-crossover study

Little evidence has demonstrated the linkage of gaseous air pollution and hospitalization rates for mental diseases among children and adolescents in China. Based on a time-stratified case-crossover design among children and adolescents in nine cities, Sichuan, a conditional logistic regression and a concentration-response (C–R) curve model were applied to investigate mental disorders in relation to gaseous air pollutants exposure at lag 0-lag 7, and lag 01-lag 07. Hospitalization costs were calculated through the attributable risk method. With daily data from official environmental monitoring centers, individual daily mean ambient pollutants estimates were evaluated via Inverse Distance Weighted method. Daily hospitalized records for mental illness were collected from medical organization or/and institutions from January 2016 to December 2019. There were 11479 inpatients suffering depression, anxiety, and/or other mental disorders. In single- and cumulative-day-lag analyses, with each 10 μg/m3 increment of NO2, SO2, and O3, the greatest odds ratio (OR) for all-cause mental disorders were 1.114 (95% confidence interval [CI]: 1.067–1.164) (lag 0), 1.219 (95% CI: 1.040–1.430) (lag 4), and 1.039 (95% CI: 1.009–1.069) (lag 7), separately. Stronger associations were found in inpatients hospitalized in warm days in SO2 analysis. C–R curve showed that all-cause mental disorders hospitalizations were positively related to SO2 and O3 exposure at relative high levels. During study period, the total economic cost of hospitalization for all-cause mental disorders caused by NO2 pollution was 94.71 million CNY. These findings indicated that gaseous air pollutants exposure may increase the risk and economic burdens of mental disorders among children and adolescents.

Relationship between short-term ozone exposure, cause-specific mortality, and high-risk populations: A nationwide, time-stratified, case-crossover study

BackgroundPrevious studies reported that short-term exposure to ground-level ozone is associated with mortality risk. However, due to the limited monitored areas, existing studies were limited in assessing the nationwide risk and suggesting specific vulnerable populations to the ozone-mortality risk. MethodsWe performed a nationwide time-stratified case-crossover study to evaluate the association between short-term ozone and cause-specific mortality in South Korea (2015–2019). A machine learning-ensemble prediction model (a test R2 > 0.96) was used to assess the short-term ozone exposure. Stratification analysis was conducted to examine the high-risk populations, and the excess mortality due to non-compliance with the WHO guideline was also assessed. ResultsFor all-cause mortality (1,343,077 cases), the risk associated with ozone (lag0– 1) was weakly identified (odd ratio: 1.005 with 95% CI: 0.997–1.014), and the risk was prominent in mortality with circulatory system diseases. In addition, based on the point estimates, the ozone-mortality risk was higher in people aged less than 65y, and this pattern was also observed in circulatory system disease deaths and urban areas. ConclusionsThis study provides national estimates of mortality risks associated with short-term ozone. Results showed that the benefits of stricter air quality standards could be greater in vulnerable populations.

Short-term exposures to temperature and risk of sudden cardiac death in women: A case-crossover analysis in the Nurses' Health Study.

Sudden cardiac death (SCD) is a major source of mortality and is the first manifestation of heart disease for most cases. Thus, there is a definite need to identify risk factors for SCD that can be modified on the population level. Short-term exposures to temperature have been implicated as a potential risk factor. Our objective was to determine if short-term temperature exposures were associated with increased risk of SCD in a US-based time-stratified case-crossover study. A total of 465 cases of SCD were identified among participants of the prospective Nurses' Health Study (NHS). Control days were selected from all other matching days of the week within the same month as the case day. Average ambient temperature on the current day (Lag0) and preceding 27 days (Lags1-27) was determined at the residence level using 800-m resolution estimates. Conditional logistic distributed lag nonlinear models (DLNMs) were used to assess the relative risk (RR) of the full range of temperature exposures over the lag period. Warmer exposures in the days before event and colder temperatures 21-28 days prior were associated with increased risks of SCD. These results were driven by associations in regions other than the Northeast and among married women. Both warm and cold ambient temperatures are suggestively associated with risks of SCD among middle-aged and older women living across the United States.

Temporal change and spatial heterogeneity of the association between ambient temperature and transport accident mortality in Japan from 1972 to 2019: a nationwide time-stratified case-crossover study

Abstract Studies have demonstrated that ambient temperature was associated with transport accidents; however, little is known about the temporal change and spatial heterogeneity of this association. This study investigated the temporal change and spatial variation in the association between temperature and transport accident mortality in Japan using daily time-series data from 1972 to 2019. First, we used time-stratified case-crossover analyses with a distributed lag nonlinear model to estimate the risks of transport accident mortality with temperature in 47 prefectures in Japan. We then pooled the estimates to obtain the risk at the country level through multivariate meta-analysis. In addition, we divided the whole time period into five sub-periods to explore temporal changes in the association and fitted the mixed-effects meta-regression to identify climatic, demographic, and socioeconomic factors that may explain the spatial heterogeneity. We found that temperature was positively associated with transport accident mortality, with a percent change (PC) of 1.47% (95% confidence interval [CI]: 1.10%, 1.85%) increase in transport accident mortality per 1 °C increase in daily mean temperature. The risk of transport accident mortality associated with temperature has decreased from 1972 [PC = 2.14% (95% CI: 1.51%, 2.77%)] to 2000 [PC = 0.89% (95% CI: 0.21%, 1.57%)] but increased slightly from 2001 [PC = 1.13% (95% CI: 0.47%, 1.48%)] to 2019 [PC = 1.60% (95% CI: 0.73%, 2.48%)]. The association between temperature and transport accident mortality was larger in relatively less developed prefectures, as explained by demographic and socioeconomic factors (e.g., total population, proportion of older people and females, and number of general hospitals). Our findings may help to better understand the association between high temperature and transport accident mortality and underlying potential mechanisms, which can provide implications for public health policies to reduce the mortality burden from transport accidents in the future.

Meteorological factors and risk of ischemic stroke, intracranial hemorrhage, and subarachnoid hemorrhage: A time-stratified case-crossover study.

Stroke risks associated with rapid climate change remain controversial due to a paucity of evidence. To examine the risk of subarachnoid hemorrhage (SAH), intracranial hemorrhage (ICH), and ischemic stroke (IS) associated with meteorological parameters. In this time-stratified case-crossover study, adult patients hospitalized for their first stroke between 2011 and 2020 from the insurance claims data in Taiwan were identified. The hospitalization day was designated as the case period, and three or four control periods were matched by the same day of the week and month of each case period. Daily mean and 24-h variations in ambient temperature, relative humidity, air pressure, and apparent temperature were measured. Conditional logistic regression models were applied to assess the risk of stroke associated with exposure to weather variables, using the third quintile as a reference, controlling for air pollutant levels. There were 7161 patients with SAH, 40,426 patients with ICH, and 107,550 patients with IS. There was an inverse linear relationship between mean daily temperature and apparent temperature with ICH. Elevated mean daily atmospheric pressure was associated with an increased risk of ICH. A greater decrease in apparent temperature over a 24-h period was associated with increased risk of ICH but decreased risk of IS (odds ratio (95% confidence interval) for the first vs. third quintile of changes in apparent temperature, 1.141 (1.053-1.237) and 0.946 (0.899-0.996), respectively). There were considerable differences in short-term associations between meteorological parameters and three main pathological types of strokes. The authors have no permission to share the data.