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This case-control study investigates the association between nonoptimum temperature and suicide death in a warming climate. Key Points: Question: How is nonoptimum temperature associated with suicide death in a warming climate? Findings: In this case-control study of 432 008 of individuals, the temperature-suicide associations were found to be approximately linear, with increasing death risks associated with higher temperature, and 15.2% of suicide deaths were associated with nonoptimal temperature nationally. It is projected that there will be consistent and drastic increases in excess suicide deaths over this century under the high-emission scenario. Meaning: Results of this nationwide case-control study suggest that higher temperature may be associated with an increase in the risk and burden of suicide death; further, results suggest a comprehensive picture of the suicide death burden under climate warming in China. Importance: Few studies have projected future suicide burden associated with daily temperatures in a warming climate. Objectives: To assess the burden of suicide death associated with daily nonoptimal temperature and to project the change of suicide burden associated with nonoptimal temperature in different regions and seasons under various climate change scenarios. Design, Setting, and Participants: Between January 1, 2013, and December 31, 2019, we conducted a time-stratified, case-control study among more than 430 000 individual suicide decedents from all counties in mainland China. Exposures: Daily meteorological data were obtained from the European Centre for Medium-Range Weather Forecasts Reanalysis Fifth Generation (ERA5) reanalysis product. Historical and future temperature series were projected under 3 scenarios of greenhouse-gas emissions from 1980 to 2099, with 10 general circulation models. Main Outcomes and Measures: The relative risk (RR) and burden of suicide death associated with nonoptimal temperature (ie, temperatures greater than or less than minimum-mortality temperature); the change of suicide burden associated with future climate warming in different regions and seasons under various climate change scenarios. Results: Of 432 008 individuals (mean [SD] age; 57.6 [19.0] years; 253 093 male [58.6%]) who died by suicide, 85.8% (370 577) had a middle school education or less. The temperature-suicide associations were approximately linear, with increasing death risks at higher temperatures. The excess risk was more prominent among older adults (ie, ≥75 years; RR, 1.71; 95% CI, 1.46-1.99) and those with low education level (ie, middle school education or less; RR, 1.46; 95% CI, 1.36-1.57). There were 15.2% suicide deaths (95% estimated CI [eCI], 14.6%-15.6%) associated with nonoptimal temperature nationally. Consistent and drastic increases in excess suicide deaths over this century were predicted under the high-emission scenario, whereas a leveling-off trend after the mid–21st century was predicted under the medium- and low-emission scenarios. Nationally, compared with the historical period (1980-2009), excess suicide deaths were predicted to increase by 8.3% to 11.4% in the 2050s and 8.5% to 21.7% in the 2090s under the 3 scenarios. The projected percentage increments of excess suicide deaths were predicted to be greater in the South (55.0%; 95% eCI, 30.5%-85.6%) and in winter (54.5%; 95% eCI, 30.4%-77.0%) in the 2090s under the high-emission scenario. Conclusions and Relevance: Findings of this nationwide case-control study suggest that higher temperature may be associated with the risk and burden of suicide death in China. These findings highlight the importance of implementing effective climate policies to reduce greenhouse gas emissions and tailoring public health policies to adapt to global warming. [ABSTRACT FROM AUTHOR]

Background: The evidence for a causal relationship between long-term ozone exposure and cardiovascular mortality is inconclusive, and most published data are from high-income countries. We aimed to investigate the association between long-term exposure to ozone and cardiovascular mortality in China, the most populous middle-income country., Methods: We did a nationwide cohort study comprising Chinese adults aged 18 years and older from the 2010-11 China Chronic Disease and Risk Factors Surveillance project; participants were followed up until Dec 31, 2018, or the date of death. Data on participants' deaths were obtained through linkage to the Disease Surveillance Point system, a national death registration database. Residential ozone exposure was estimated with a previously developed random forest model. We applied stratified Cox proportional hazards models to estimate the associations of ozone with mortality due to overall cardiovascular diseases, ischaemic heart disease, and stroke. The models were stratified by age and sex and adjusted for a set of individual-level and regional covariates. Warm-season average ozone concentration for the previous 1-3 years was added as a time-varying variable. We also did subgroup analyses by age, sex, level of education, smoking status, urban or rural residence, and geographical region., Findings: Data were analysed for 96 955 participants. The warm-season average ozone concentration during the follow-up period was 89·7 μg/m 3 (SD 14·4). In the fully adjusted models, we observed significant and positive associations between ozone and mortality from overall cardiovascular diseases (hazard ratio [HR] 1·093 [95% CI 1·046-1·142] per 10 μg/m 3 increase in warm-season ozone concentrations), ischaemic heart disease (1·184 [1·099-1·276] per 10 μg/m 3 increase in warm-season ozone concentrations), and stroke (1·063 [1·002- 1·128] per 10 μg/m 3 increase in warm-season ozone concentrations). After adjusting for fine particulate matter, the associations with overall cardiovascular disease and ischaemic heart disease mortality were almost unchanged, whereas the association with stroke mortality lost statistical significance. The association of long-term ozone exposure with cardiovascular mortality was more prominent in people aged 65 years and older than in those younger than 65 years. We did not find any effect modification of sex, level of education, smoking status, urban or rural residence, and geographical region. We observed an almost linear exposure-response relationship between ozone and cardiovascular mortality., Interpretation: This study is, to the best of our knowledge, the first nationwide cohort study to show that long-term ozone exposure contributes to elevated risks of cardiovascular mortality, particularly from ischaemic heart disease, in a middle-income setting. The exposure-response function generated from this study could potentially inform future air quality standard revisions and environmental health impact assessments., Funding: National Natural Science Foundation of China., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: The use of e-cigarettes among adults is increasing globally. Since 2018, policies in China have restricted e-cigarette use; however, little information is available on the national trend in e-cigarette use before regulations were implemented. Therefore, we sought to estimate the trend in e-cigarette use in China before policy implementation and explored associated factors., Methods: We assessed two nationally representative cross-sectional datasets from the China Chronic Disease and Nutrition Surveillance (CCDNS) surveys initiated in 2015 (June, 2015, to May, 2016) and 2018 (August, 2018, to June, 2019). The surveys were done at 298 national disease surveillance points in 31 provinces in mainland China, and used a multistage, stratified, cluster-randomised sampling design, recruiting community-based Chinese adults aged 18 years and older. Within the standard CCDNS survey, face-to-face questionnaire interviews were used to collect self-report data on e-cigarette use in the preceding 30 days. E-cigarette users were those who self-reported e-cigarette use on 1 day or more in the past 30 days. Prevalence estimates of past 30-day e-cigarette use were weighted to represent the Chinese adult population accounting for the complex sampling design. Populations for the years 2015-16 and 2018-19 were standardised with the 2010 population census to gain comparable estimates. Multivariable logistic regression models adjusted for age, sex, urban or rural residence, household income, occupation, and education level were applied to identify factors associated with the likelihood of e-cigarette use among the total population, ever smokers (current and former), and never smokers across both surveys., Findings: Our study included 189 306 Chinese adults from the 2015 survey (100 405 [53·0%] women; mean age 43·6 years [SD 14·6]) and 184 475 Chinese adults from the 2018 survey (102 373 [55·5%] women; mean age 43·4 years [13·9]). The weighted prevalence of past 30-day e-cigarette use among Chinese adults increased from 1·3% (95% CI 1·1-1·5%) in 2015-16 to 1·6% (95% CI 1·4-1·8%) in 2018-19 (an increase of 0·3% [95% CI 0·1-0·6]; Rao-Scott χ 2 p=0·0086). Based on weighted proportion data, e-cigarette users were predominantly men (97·4% [95% CI 96·7-98·1] in 2015-16 and 97·0% [95·4-98·6] in 2018-19) and current conventional smokers (93·0% [90·7-95·2] in 2015-16 and 96·2% [95·1-97·3] in 2018-19). Across both surveys, the odds of e-cigarette use were significantly associated with obesity (odds ratio 1·6 [95% CI 1·3-2·1]; p=0·0007), awareness of smoking hazards (1·2 [1·0-1·4]; p=0·022), and smoking status (in current smokers, 135·2 [87·7-208·6]; and in former smokers, 33·5 [21·3-52·7]; p<0·0001). Among current smokers, the odds were increased with daily cigarette consumption (2·1 [1·5-2·8]; p<0·0001), smoking more than 20 cigarettes per day (1·8 [1·5-2·3]; p<0·0001), and an attempt to quit smoking (within the past 12 months, 1·9 [1·5-2·4]; and before the past 12 months, 1·5 [1·3-1·9]; p<0·0001). In never smokers, the odds were increased in those aware of the hazards of smoking (2·4 [1·2-4·7]; p=0·011)., Interpretation: E-cigarette use in China remains low but has increased substantially between 2015 and 2019. Our study identified increased e-cigarette use among subpopulations, and use patterns, that warrant further attention from public health policy makers in China., Funding: Chinese Central Government, National Key Research and Development Program of China., (Copyright © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)