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Abstract Background Stroke is a leading cause of death globally. Extreme temperatures may induce stroke, but evidence on the effects of heat on first-ever strokes is not clear. Low air pressure can lead to depression and an increase in blood pressure, and it may exacerbate the health impact of heat. In this study, we aimed to evaluate the effects of heat on first-ever strokes, the possible sensitive populations, and the effect of modification of atmospheric pressure. Methods We collected data on 142,569 first-ever strokes during 2005–2016 in Shenzhen, a coastal city in southern China, with subtropical oceanic monsoon climate. We fitted a time-series Poisson model in our study, estimating the association between daily mean temperature and first-ever strokes in hot months, with a distributed lag non-linear model with 7 days of lag. We calculated strokes attributable to heat in various gender, age groups, household register types, stroke subtypes, and atmospheric pressure levels. Results Heat had a significant cumulative association with first-ever strokes, and the risk of strokes increased with the rise in temperature after it was higher than 30 °C (the 85th percentile). In total, 1.95% (95% empirical CI 0.63–3.20%) of first-ever strokes were attributable to high temperature. The attributable fraction and attributable number of heat were statistically significant in male, female, middle-aged and old patients, immigrant patients, and CBI patients. The fraction attributable to heat was 3.33% in the low atmospheric pressure group, and the number of estimated daily attributable strokes at low atmospheric pressure levels was higher than that of medium and high atmospheric pressure levels (p < 0.01). Conclusions High temperatures in hot months may trigger first-ever strokes, and low atmospheric pressure may exacerbate the effect. We mainly found associations between heat and first-ever strokes for intracerebral hemorrhage, middle-aged and old patients, as well as immigrant patients. Graphical abstract Unlabelled Image Highlights • High temperatures in hot months may trigger first-ever strokes. • Low atmospheric pressure may exacerbate the effects of heat on first-ever strokes. • Middle-aged and old patients, immigrants, as well as cerebral infarction patients were sensitive to heat. [ABSTRACT FROM AUTHOR]

The impact of ambient air pollution on pregnant women is a concern in China. However, little is known about the association between air pollution and preeclampsia and the potential modifying effects of meteorological conditions have not been assessed. This study aimed to assess the effects of prenatal exposure to air pollution on preeclampsia, and to explore whether temperature and humidity modify the effects. We performed a retrospective cohort study based on 1.21 million singleton births from the birth registration system in Shenzhen, China, between 2005 and 2012. Daily average measurements of particulate matter <10 μm (PM 10 ), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), air temperature (T), and dew point (T d ) were collected. Logistic regression models were performed to estimate associations between air pollution and preeclampsia during the first and second trimesters, and during the entire pregnancy. In each time window, we observed a positive gradient of increasing preeclampsia risk with increasing quartiles of PM 10 and SO 2 exposure. When stratified by T and T d in three categories (<5th, 5th −95th, and >95th percentile), we found a significant interaction between PM 10 and T d on preeclampsia; the adverse effects of PM 10 increased with T d . During the entire pregnancy, there was a null association between PM 10 and preeclampsia under T d  < 5th percentile. Preeclampsia risk increased by 23% (95% CI: 19–26%) when 5th < T d  < 95th percentile, and by 34% (16–55%) when T d  > 95th percentile. We also found that air pollution effects on preeclampsia in autumn/winter seasons were stronger than those in the spring/summer. This is the first study to address modifying effects of meteorological factors on the association between air pollution and preeclampsia. Findings indicate that prenatal exposure to PM 10 and SO 2 increase preeclampsia risk in Shenzhen, China, and the effects could be modified by humidity. Pregnant women should limit air pollution exposure, particularly during humid periods. [ABSTRACT FROM AUTHOR]

Background Compared with cold- and heat-related health impacts, the evidence was very limited in assessing the mortality effects of temperature variation (TV) accounting for both intra-day and inter-day changes in temperature. Objective We used a newly proposed composite indicator of intra-day and inter-day TV and evaluated TV-mortality associations in Hubei, China at the provincial level. Methods Daily mortality and meteorological data during 2009–2012 were obtained from 12 urban and rural counties across Hubei Province in China. TV was calculated using the standard deviation of the minimum and maximum temperatures during the exposure days. A quasi-Poisson generalized linear regression combined with distributed lag non-linear model was first applied to estimate county-specific relationship between mortality and TV, adjusting for long-term trend and seasonality, mean temperature, relative humidity, public holiday, and day of the week. A meta-analysis was then conducted to pool the county-specific estimates of TV-related mortality effects. Results A significant positive association was observed between TV and cause-specific mortality (except for respiratory mortality and ischemic heart disease mortality). The effect estimates varied by exposure days, with the highest at 0–7 days. Season-stratified analyses showed similar results, while stronger TV-mortality associations were found in warm season than in cold season. The elderly were more susceptible to TV-related mortality effects than younger groups. Some slight differences in effect estimates were also observed in subgroups stratified by gender, education attainment, place of death, and urban/rural areas. Conclusion Our study strengthened the evidence that temperature variation was an independent risk factor for non-accidental mortality. Some preventive and intervention strategies should be efficiently developed in response to global climate change, so as to minimize public health burden due to unstable weather patterns. [ABSTRACT FROM AUTHOR]

• The first study to examine heat-related diabetes mortality nationwide in Thailand. • High temperatures increased mortality risks from diabetes and the effects are spatially heterogenous. • Higher level of greenness was associated with lower heat-related mortality risk. Diabetes is a major public health problem globally, and heat exposure may be a potential risk factor for death among diabetes. This study examines the association between heat and diabetes mortality in different regions of Thailand and investigates whether heat effects are modified by regional greenness. Daily temperature and daily diabetes deaths data were obtained for 60 provinces of Thailand during 2000–2008. A case-crossover analysis was conducted to quantify the odds of heat-related death among diabetes. Meta-regression was then used to examine potential modification effects of regional greenness (as represented by the Normalized Difference Vegetation Index) on heat-related mortality. A strong association between heat and diabetes mortality was found in Thailand, with important regional variations. Nationally, the pooled odds ratio of diabetes mortality was 1.10 (95% confidence interval (CI): 1.06–1.14) for heat (90th percentile of temperature) and 1.20 (95% CI: 1.10–1.30) for extreme heat (99th percentile of temperature) compared with the minimum mortality temperature, across lag 0–1 days. Central and northeast Thailand were the most vulnerable regions. Regional greenness modified the effects of heat, with lower mortality impacts in areas of higher levels of greenness. In conclusion, heat exposure increases mortality risk in diabetes, with large geographical variations in risk suggesting the need for region-specific public health strategies. Increasing greenness levels may help to reduce the burden of heat on diabetes in Thailand against the backdrop of a warming climate. [ABSTRACT FROM AUTHOR]

Abstract Background Climate change has exacerbated the health effects of high ambient temperatures on occupational health and safety; however, to what extent heat stress can induce workplace injuries and economic costs is poorly studied. This study aimed to quantify the attributable fractions of injury claims and subsequent insurance payouts using data from work-related injury insurance system in Guangzhou, China. Methods Individual workers' injury claims data were collected for the period of 2011–2012, including demographic characteristics and work-related information. Daily maximum wet bulb globe temperature (WBGT, °C) was calculated from meteorological data. To examine the association between WBGT index and work-related injury, we fit a quasi-Poisson regression with distributed lag non-linear model. Then we calculated the numbers of injury claims and costs of insurance compensations attributable to days with WBGT above the heat stress limit according to the national occupational health standards. Results There were 9550 work-related injury claims, resulting in an insurance payout of 282.3 million Chinese Yuan. The risks of injury claims increased with rising WBGT. 4.8% (95% eCI: 2.9%–6.9%) of work-related injuries and 4.1% (95% eCI: 0.2%–7.7%) of work-related injury insurance payouts were attributed to heat exposure for WBGT threshold above the heat stress limit. Male workers, those in small enterprises and with low educational attainment were especially sensitive to the effects of heat exposure. Conclusions Heat stress can contribute to higher risk of work-related injury and substantial economic costs. Quantified the impacts of injuries and related economic costs should be considered to develop targeted preventive measures in the context of climate change. Graphical abstract Unlabelled Image Highlights • High WBGT contributed to increased risks of work injuries. • Substantial costs were attributable to heat stress due to excessive injury claims. • Workers in small enterprises and with low educational attainment were most affected. [ABSTRACT FROM AUTHOR]

Abstract Ambient air pollution has been linked to small for gestational age (SGA); however, the relationship with large for gestational age (LGA) is unclear and very few studies have investigated seasonal effects on the association between air pollution and SGA or LGA. Using birth registry data of 506,000 singleton live births from 11 districts in Guangzhou, China between January 2015 and July 2017, we examined associations between ambient air pollutants (PM 2.5 , PM 10 , NO 2 , SO 2 , and O 3) and SGA/LGA, and further assessed the modification effect of season. Daily concentrations of air pollutants from 11 monitoring stations were used to estimate district-specific exposures for each participant based on their district of residence during pregnancy. Two-level binary logistic regression models were used to evaluate associations between air pollution and SGA/LGA. Stratified analyses by season and a Cochran Q test were performed to assess the modification of season. Exposure to PM 2.5 , NO 2 , SO 2 , and O 3 was significantly associated with increased risk of SGA, especially for exposure during the second and third trimester. For an interquartile range (IQR) increase in PM 2.5 (6.5 μg/m3), NO 2 (12.7 μg/m3), SO 2 (2.8 μg/m3) and O 3 (20.8 μg/m3) during the entire pregnancy, SGA risk increased by 2% (OR = 1.02, 95% CI: 1.00–1.04), 8% (OR = 1.08, 95% CI: 1.04–1.12), 2% (OR = 1.02, 95% CI: 1.01–1.03), and 14% (1.14, 1.11–1.17), respectively. A decreased risk of LGA was found for PM 2.5 , PM 10 , SO 2 , and O 3 during the first trimester or entire pregnancy. When examined by season, significant associations between air pollutants and SGA were observed for women who conceived during summer or fall, and the patterns were consistent for all pollutants. Our study suggests that conception during different seasons might modify the association between ambient air pollution and SGA. Graphical abstract Unlabelled Image Highlights • Prenatal PM 2.5 , NO 2 , SO 2 , and O 3 exposures increased the risk of SGA. • Prenatal exposure to PM 2.5 , PM 10 , SO 2 , and O 3 decreased the risk of LGA. • Effects of prenatal air pollution exposure on SGA may be modified by season. • Effects of air pollution on SGA were observed for pregnancies conceived in summer or fall. [ABSTRACT FROM AUTHOR]

Abstract Maternal exposure to ambient air pollution has been associated with preterm birth (PTB), however, entire pregnancy or trimester-specific associations were generally reported, which may not sufficiently identify windows of susceptibility. Using birth registry data from Guangzhou, a megacity of southern China (population ~14.5 million), including 469,975 singleton live births between January 2015 and July 2017, we assessed the association between weekly air pollution exposure and PTB in a retrospective cohort study. Daily average concentrations of PM 2.5 , PM 10 , NO 2 , SO 2 , and O 3 from 11 monitoring stations were used to estimate district-specific exposures for each participant based on their district residency during pregnancy. Distributed lag models (DLMs) incorporating Cox proportional hazard models were applied to estimate the association between weekly maternal exposure to air pollutant and PTB risk (as a time-to-event outcome), after controlling for temperature, seasonality, and individual-level covariates. We also considered moderate PTB (32–36 gestational weeks) and very PTB (28–31 gestational weeks) as outcomes of interest. Hazard ratios (HRs) and 95% confidential intervals (95% CIs) were calculated for an interquartile range (IQR) increase in air pollutants during the study period. An IQR increase in PM 2.5 exposure during the 20th to 28th gestational weeks (27.0 μg/m3) was significantly associated with PTB risk, with the strongest effect in the 25th week (HR = 1.034, 95% CI:1.010–1.059). The significant exposure windows were the 19th–28th weeks for PM 10 , the 18th–31st weeks for NO 2 , and the 23rd–31st weeks for O 3 , respectively. The strongest associations were observed in the 25th week for PM 10 (IQR = 37.0 μg/m3; HR = 1.048, 95% CI:1.034–1.062), the 26th week for NO 2 (IQR = 29.0 μg/m3; HR = 1.060, 95% CI:1.028–1.094), and in the 28th week for O 3 (IQR = 90.0 μg/m3; HR = 1.063, 95% CI:1.046–1.081). Similar patterns were observed for moderate PTB (32–36 gestational weeks) and very PTB (28–31 gestational weeks) for PM 2.5 , PM 10 , NO 2 exposure, but the effects were greater for very PTB. We did not observe any association between pregnancy SO 2 exposure and the risk of PTB. Our results suggest that middle to late pregnancy is the most susceptible air pollution exposure window for air pollution and PTB among women in Guangzhou, China. Highlights • Limited studies identified susceptible windows for prenatal air pollution and preterm birth at a weekly level. • Prenatal PM 2.5 , PM 10 , NO 2 , and O 3 exposure is associated with preterm birth. • The most susceptible exposure window for each pollutant is gestational weeks 18–31. • Distributed lag models are applicable for identifying the susceptible windows. [ABSTRACT FROM AUTHOR]

Background: Despite increasing concerns about the health effects of climate change, the extent to which workers are affected by hot weather is not well documented. This study aims to investigate the association between high temperatures and work-related injuries using data from a large subtropical city in China.Methods: We used workers' compensation claims to identify work-related injuries in Guangzhou, China during 2011-2012. To feature the heat effect, the study period was restricted to the warm seasons in Guangzhou (1 May-31 October). We conducted a time-stratified case-crossover study to examine the association between ambient outdoor temperatures, including daily maximum and minimum temperatures, and cases of work-related injury. The relationships were assessed using conditional Poisson regression models.Results: Overall, a total of 5418 workers' compensation claims were included over the study period. Both maximum and minimum temperatures were significantly associated with work-related injuries, but associations varied by subgroup. One °C increase in maximum temperature was associated with a 1.4% (RR = 1.014, 95%CIs 1.012-1.017) increase in daily injury claims. Significant associations were seen for male and middle-aged workers, workers in small and medium-sized enterprises, and those working in manufacturing sector. And 1 °C increase in minimum temperature was associated with 1.7% (RR = 1.017, 95%CIs 1.012-1.021) increase in daily injury claims. Significant associations were observed for female and middle-aged workers, workers in large-sized enterprises, and those working in transport and construction sectors.Conclusions: We found a higher risk of work-related injuries due to hot weather in Guangzhou, China. This study provides important epidemiological evidence for policy-makers and industry that may assist in the formulation of occupational safety and climate adaptation strategies. [ABSTRACT FROM AUTHOR]