Seasonal variations of temperature-related mortality burden from cardiovascular disease and myocardial infarction in China

Association between synoptic types in Beijing and acute myocardial infarction hospitalizations: A comprehensive analysis of environmental factors

BACKGROUND

Environmental factors like air pollution and temperature can trigger acute myocardial infarction (AMI). However, the link between large-scale weather patterns (synoptic types) and AMI admissions has not been extensively studied. This research aimed to identify the different synoptic air types in Beijing and investigate their association with AMI occurrences.

METHODS

We analyzed data from Beijing between 2013 and 2019, encompassing 2556 days and 149,632 AMI cases. Using principal component analysis and hierarchical clustering, classification into distinct synoptic types was conducted based on weather and pollution measurements. To assess the impact of each type on AMI risk over 14 days, we employed a distributed lag non-linear model (DLNM), with the reference being the lowest risk type (Type 2).

RESULTS

Four synoptic types were identified: Type 1 with warm, humid weather; Type 2 with warm temperatures, low humidity, and long sunshine duration; Type 3 with cold weather and heavy air pollution; and Type 4 with cold temperatures, dryness, and high wind speed. Type 4 exhibited the greatest cumulative relative risk (CRR) of 1.241 (95%CI: 1.150, 1.339) over 14 days. Significant effects of Types 1, 3, and 4 on AMI events were observed at varying lags: 4-12 days for Type 1, 1-6 days for Type 3, and 1-11 days for Type 4. Females were more susceptible to Types 1 and 3, while individuals younger than 65 years old showed increased vulnerability to Types 3 and 4.

CONCLUSION

Among the four synoptic types identified in Beijing from 2013 to 2019, Type 4 (cold, dry, and windy) presented the highest risk for AMI hospitalizations. This risk was particularly pronounced for males and people under 65. Our findings collectively highlight the need for improved methods to identify synoptic types. Additionally, developing a warning system based on these synoptic conditions could be crucial for prevention.

Residuals in space: Potential pitfalls and applications from single-institution survival analysis

In practice, survival analyses appear in pharmaceutical testing, procedural recovery environments, and registry-based epidemiological studies, each reasonably assuming a known patient population. Less commonly discussed is the additional complexity introduced by non-registry and spatially-referenced data with time-dependent covariates in observational settings. In this short report we discuss residual diagnostics and interpretation from an extended Cox proportional hazard model intended to assess the effects of wildfire evacuation on risk of a secondary cardiovascular events for patients of a specific healthcare system on the California's central coast. We describe how traditional residuals obscure important spatial patterns indicative of true geographical variation, and their impacts on model parameter estimates. We briefly discuss alternative approaches to dealing with spatial correlation in the context of Bayesian hierarchical models. Our findings/experience suggest that careful attention is needed in observational healthcare data and survival analysis contexts, but also highlights potential applications for detecting observed hospital service areas.

Association Between Nutrients and Cardiovascular Diseases

Cardiovascular diseases (CVD) constitute a leading cause of global mortality. Inflammation and oxidative stress are key molecular underpinnings of CVD pathogenesis. This comprehensive review explores the multifaceted role of nutrients in cardiovascular health beyond their impact on cardiac events. The manuscript examines the influence of macronutrients such as fats and carbohydrates, as well as micronutrients including vitamins and folate, on CVD. Additionally, the interplay between dietary supplements and CVD risk reduction is investigated. The purpose of this manuscript is to provide a comprehensive overview of the diverse mechanisms through which nutrients contribute to cardiovascular well-being, addressing both cardioprotective effects and their broader implications. Through an analysis of pertinent studies, we illuminate the complex relationship between nutrition, lifestyle, and cardiovascular health, underscoring the significance of a holistic approach to CVD prevention and management.

Nonoptimum Temperatures Are More Closely Associated With Fatal Myocardial Infarction Than With Nonfatal Events

BACKGROUND

Ambient temperatures trigger hospitalisation, mortality, and emergency department visits for myocardial infarction (MI). However, nonoptimum temperature-related risks of fatal and nonfatal MI have not yet been compared.

METHODS

From 2007 to 2019, 416,894 MI events (233,071 fatal and 183,823 nonfatal) were identified in Beijing, China. A time-series analysis with a distributed-lag nonlinear model was used to compare the relative and population-attributable risks of fatal and nonfatal MI associated with nonoptimum temperatures.

RESULTS

The reference was the optimum temperature of 24.3°C. For single-lag effects, cold (-5.2°C) and heat (29.6°C) effects had associations that persisted for more days for fatal MI than for nonfatal MI. For cumulative-lag effects over 0 to 21 days, cold effects were higher for fatal MI (relative risk [RR] 1.99, 95% confidence interval [CI] 1.68-2.35) than for nonfatal MI (RR 1.60, 95% CI 1.32-1.94) with a P value for difference in effect sizes of 0.048. In addition, heat effects were higher for fatal MI (RR 1.33, 95% CI 1.24-1.44) than for nonfatal MI (RR 0.99, 95% CI 0.91-1.08) with a P value for difference in effect sizes of 0.002. The attributable fraction of nonoptimum temperatures was higher for fatal MI (25.6%, 95% CI 19.7%-30.6%) than for nonfatal MI (19.1%, 95% CI 12.1%-25.0%).

CONCLUSIONS

Fatal MI was more closely associated with nonoptimum temperatures than nonfatal MI, as evidenced by single-lag effects that have associations which persisted for more days, higher cumulative-lag effects, and higher attributable risks for fatal MI. Strategies are needed to mitigate the adverse effects of nonoptimum temperatures.

Urban climate and cardiovascular health: Focused on seasonal variation of urban temperature, relative humidity, and PM2.5 air pollution

Seasonal effects on subclinical cardiovascular functions (CVFs) are an important emerging health issue for people living in urban environment. The objectives of this study were to demonstrate the effects of seasonal variations of temperature, relative humidity, and PM2.5 air pollution on CVFs. A total of 86 office workers in Taipei City were recruited, their arterial pressure waveform was recorded by cuff sphygmomanometer using an oscillometric blood pressure (BP) device for CVFs assessment. Results of paried t-test with Bonferroni correction showed significantly increased systolic and diastolic BP (SBP, DBP), central end-systolic and diastolic BP (cSBP, cDBP) and systemic vascular resistance, but decreased heart rate (HR), stroke volume (SV), cardio output (CO), and cardiac index in winter compared with other seasons. After controlling for related confounding factors, SBP, DBP, cSBP, cDBP, LV dp/dt max, and brachial-ankle pulse wave velocity (baPWV) were negatively associated with, and SV was positively associated with seasonal temperature changes. Seasonal changes of air pollution in terms of PM2.5 were significantly positively associated with DBP and cDBP, as well as negatively associated with HR and CO. Seasonal changes of relative humidity were significantly negatively associated with DBP, and cDBP, as well as positively associated with HR, CO, and baPWV. This study provides evidence of greater susceptibility to cardiovascular events in winter compared with other seasons, with ambient temperature, relative humidity, and PM2.5 as the major factors of seasonal variation of CVFs.

Exposure to outdoor artificial light at night increases risk and burden of metabolic disease in Ningxia, China

Nearly a quarter of the world's land has already been polluted by artificial light. And numerous human and animal studies have corroborated that light at night can disrupt metabolism. Therefore, we aimed to estimate the association between outdoor artificial light at night (ALAN) and the presence of metabolic disease. Daily hospital admission cases from Ningxia, China, between 2014 and 2020 were included. Cumulative associations between outdoor ALAN and metabolic disease were estimated using logistic regression and distributed lagged non-linear models (DLNM) with lags of 0-30 days and stratified analysis by age groups and gender. The results suggest that 26.80% of metabolic disease cases in Ningxia can be attributed to outdoor ALAN and that men, especially in men aged 46-59 years, are more susceptible to lighting. Policymakers need to develop measures and facilities in corresponding areas, such as universal access to indoor blackout curtains. In particular, men should be urged to minimize going outside at night and to develop protective measures specifically for men.

What happened when medical staff in Beijing, China wore over-apron dosemeters?

The wearing method of personal dosemeters for medical staff changed from under to outside the operator's protective apron in April 2020. We measured the radiation dose Hp(10) for medical staff in Beijing from September 2020 to October 2021. The study population consisted of 3291 medical staff. All participants were divided into three groups. After excluding unusually low doses, the collected data higher than the detection limit involved 811 (7.8%) of 10 395 readings from 479 (14.6%) of 3291 staff. The mean equivalent dose was 1.4 mSv/3 months, with an SD of 2.3 mSv. The calculated average annual effective doses of radiation workers in the three groups after the interventional procedures from September 2020 to October 2021 ranged from 0.47 to 0.63 mSv/year, with median values of 0.32, 0.23 and 0.26 mSv/year, respectively.

Joint Exposure to Ambient Air Pollutants Might Elevate the Risk of Small for Gestational Age (SGA) Infants in Wuhan: Evidence From a Cross-Sectional Study

Objective: To investigate the effect of exposure to multiple ambient air pollutants during pregnancy on the risk of children being born small for gestational age (SGA). Methods: An Air Pollution Score (APS) was constructed to assess the effects of being exposed to six air pollutants simultaneously, PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ (referred to as joint exposure). A logistic regression model was applied to estimate the associations of APS and SGA. Results: The adjusted odds ratios (ORs) of SGA per 10 ug/m³ increased in APS during the first and second trimesters and the entire pregnancy were 1.003 [95% confidence intervals (CIs): 1.000, 1.007], 1.018 (1.012, 1.025), and 1.020 (1.009, 1.031), respectively. The ORs of SGA for each 10 μg/m³ elevated in APS during the whole pregnancy were 1.025 (1.005, 1.046) for mothers aged over 35 years old vs. 1.018 (1.005, 1.031) for mothers aged under 35 years old. Women who were pregnant for the first time were more vulnerable to joint ambient air pollution. Conclusion: In summary, the results of the present study suggested that joint exposure to ambient air pollutants was associated with the increment in the risks of SGA.

Mathematical modeling in the health risk assessment of air pollution-related disease burden in China: A review

This review paper covers an overview of air pollution-related disease burden in China and a literature review on the previous studies which have recently adopted a mathematical modeling approach to demonstrate the relative risk (RR) of air pollution-related disease burden. The associations between air pollution and disease burden have been explored in the previous studies. Therefore, it is necessary to quantify the impact of long-term exposure to ambient air pollution by using a suitable mathematical model. The most common way of estimating the health risk attributable to air pollution exposure in a population is by employing a concentration-response function, which is often based on the estimation of a RR model. As most of the regions in China are experiencing rapid urbanization and industrialization, the resulting high ambient air pollution is influencing more residents, which also increases the disease burden in the population. The existing RR models, including the integrated exposure-response (IER) model and the global exposure mortality model (GEMM), are critically reviewed to provide an understanding of the current status of mathematical modeling in the air pollution-related health risk assessment. The performances of different RR models in the mortality estimation of disease are also studied and compared in this paper. Furthermore, the limitations of the existing RR models are pointed out and discussed. Consequently, there is a need to develop a more suitable RR model to accurately estimate the disease burden attributable to air pollution in China, which contributes to one of the key steps in the health risk assessment. By using an updated RR model in the health risk assessment, the estimated mortality risk due to the impacts of environment such as air pollution and seasonal temperature variation could provide a more realistic and reliable information regarding the mortality data of the region, which would help the regional and national policymakers for intensifying their efforts on the improvement of air quality and the management of air pollution-related disease burden.

Assessing myocardial infarction severity from the urban environment perspective in Wuhan, China

Health inequalities are globally widespread due to the regional socioeconomic inequalities. Myocardial infarction (MI) is a leading health problem causing deaths worldwide. Yet medical services for it are often inequitably distributed by region. Moreover, studies concerning MI's potential spatial risk factors generally suffer from difficulties in focusing on too few factors, inappropriate models, and coarse spatial grain of data. To address these issues, this paper integrates registered 1098 MI cases and urban multi-source spatio-temporal big data, and spatially analyses the risk factors for MI severity by applying an advanced interpretable model, the random forest algorithm (RFA)-based SHapley Additive exPlanations (SHAP) model. In addition, a community-scale model between spatio-temporal risk factors and MI cases is constructed to predict the MI severity of all communities in Wuhan, China. The results suggest that those risk factors (i.e., age of patients, medical quality, temperature changes, air pollution and urban habitat) affect the MI severity at the community scale. We found that Wuhan residents in the downtown area are at risk for high MI severity, and the surrounding suburb areas show a donut-shape pattern of risk for medium-to-high MI severity. These patterns draw our attention to the impact of spatial environmental risk factors on MI severity. Thus, this paper provides three recommendations for urban planning to reduce the risk and mortality from severe MI in the aspect of policy implication.

Impact of meteorological factors on hospital admissions for spinal diseases in Shanghai during 2015-2019

PURPOSE

To assess the correlation between meteorological factors and spinal disease admissions.

METHODS

Data was obtained from the electronic medical records of a tertiary general hospital. Meteorological data was collected from China Meteorological Science Data Sharing Service. Distributed lag nonlinear models were used to evaluate the impact of meteorological variables on weekly spinal disease admissions.

RESULTS

A total of 2739 spinal cases were documented. Compared with estimates at the 50^th, the cumulative relative risk (RR) for extremely high temperatures at the 97.5^th over lag week 18 to lag week 20 increased by 75.7%. When the weekly maximum temperature reached 38°C during lag week 20, the maximum RR was 1.96 (95% CI:1.095-3.506). Moreover, the effects of extremely high temperatures on spinal disease admissions were more obvious in females and the age group ≥65 years old compared with males and the age group<65 years old.

CONCLUSIONS

Extremely high temperatures were significantly associated with higher risks of spinal disease admissions.

Non-optimum temperature increases risk and burden of acute myocardial infarction onset: A nationwide case-crossover study at hourly level in 324 Chinese cities

BACKGROUND

The associations of ambient temperature with acute myocardial infarction (AMI) have seldom been examined based on the time of symptom onset.

METHODS

We conducted a time-stratified case-crossover study among 1,046,773 eligible AMI patients from 2,093 hospitals in 324 Chinese cities from January 1, 2015 to June 30, 2021, after excluding those transferred from other hospitals or having not reported the time of symptom onset. Hourly exposure to ambient temperature was calculated as multiple moving 24-h averages (days) before hourly onset of AMI symptoms. Conditional logistic regression and distributed lag non-linear models with a duration of 0-21 days were used to estimate the cumulative associations of non-optimum temperature with AMI onset and the corresponding disease burden nationally. Subgroup analyses by region and period were conducted. Specifically, cities with and without centralized heating system were classified into heating and non-heating regions, respectively. The whole year in heating region was divided into heating and non-heating periods based on the duration of centralized heating in each city.

FINDINGS

Almost monotonically increasing risks were observed for both overall AMI and its two subtypes when ambient temperature declined. The effects of extremely low temperature occurred immediately on the concurrent day, and lasted up to almost 3 weeks. The excess risks of AMI onset associated with non-optimum ambient temperatures were observed during the whole year in the non-heating region and non-heating period in the heating region, but not during heating period. Specifically, odds ratios of AMI onset associated with extremely low temperature cumulated over 0-21 days were 1.24 (95% CI: 1.13-1.37), 1.46 (95% CI: 1.20-1.76), and 1.62 (95% CI: 1.46-1.81) in the heating region during non-heating period, in the non-heating region during winter and non-winter period, respectively. The heat effects on AMI onset were very modest and transient. Totally, 13.26% of AMI cases could be attributable to non-optimum temperatures nationally. The burden of AMI attributable to non-optimum temperature was much smaller in heating region than in non-heating region. Somewhat stronger effects were observed in females and patients aged older than 65.

INTERPRETATION

This nationwide study provided robust evidence that non-optimum ambient temperature may significantly trigger AMI onset, and for the first time estimated the disease burden after accounting for spatial and seasonal heterogeneity. Centralized heating might substantially mitigate AMI burden due to non-optimum temperature.

FUNDING

Shanghai International Science and Technology Partnership Project, National Natural Science Foundation of China, Talent Training Program of Zhongshan Hospital, Fudan University.

No Impact of Seasonality of Diagnoses on Baseline Tumor Immune Infiltration, Response to Treatment, and Prognosis in BC Patients Treated with NAC

Simple Summary

High tumor-infiltrating lymphocyte (TIL) levels are associated with an increased response to neoadjuvant chemotherapy (NAC) in breast cancer (BC). The seasonal fluctuation of TILs in breast cancer is poorly documented. In this study, we compared pre- and post-treatment immune infiltration, the treatment response as assessed by means of pathological complete response (pCR) rates, and survival according to the seasonality of BC diagnoses in a clinical cohort of patients treated with NAC. We found no association between seasonality and baseline TIL levels or pCR rates. We found that post-NAC stromal lymphocyte infiltration was lower when cancer was diagnosed in the summer, especially in the subgroup of patients with TNBC. Our data do not support the hypothesis that the seasonality of diagnoses has a major impact on the natural history of BC treated with NAC.

Abstract

Breast cancer (BC) is the most common cancer in women worldwide. Neoadjuvant chemotherapy (NAC) makes it possible to monitor in vivo response to treatment. Several studies have investigated the impact of the seasons on the incidence and detection of BC, on tumor composition, and on the prognosis of BC. However, no evidence is available on their association with immune infiltration and the response to treatment. The objective of this study was to analyze pre- and post-NAC immune infiltration as assessed by TIL levels, the response to treatment as assessed by pathological complete response (pCR) rates, and oncological outcomes as assessed by relapse-free survival (RFS) or overall survival (OS) according to the seasonality of BC diagnoses in a clinical cohort of patients treated with neoadjuvant chemotherapy. Out of 1199 patients, the repartition of the season at BC diagnosis showed that 27.2% were diagnosed in fall, 25.4% in winter, 24% in spring, and 23.4% in summer. Baseline patient and tumor characteristics, including notable pre-NAC TIL levels, were not significantly different in terms of the season of BC diagnosis. Similarly, the pCR rates were not different. No association for oncological outcome was identified. Our data do not support the idea that the seasonality of diagnoses has a major impact on the natural history of BC treated with NAC.

Cause-specific cardiovascular disease mortality attributable to ambient temperature: A time-stratified case-crossover study in Jiangsu province, China

BACKGROUND

Exposure to non-optimum ambient temperature has been linked to increased risk of total cardiovascular disease (CVD) mortality; however, the adverse effects on mortality from specific types of CVD remain less understood.

OBJECTIVES

To comprehensively investigate the association of ambient temperature with cause-specific CVD mortality, and to estimate and compare the corresponding mortality burden.

METHODS

We conducted a time-stratified case-crossover study of 1000,014 CVD deaths in Jiangsu province, China during 2015-2019 using data from the China National Mortality Surveillance System. Residential daily 24-hour average temperature for each subject was extracted from a validated grid data at a spatial resolution of 0.0625° × 0.0625°. We fitted distributed lag non-linear models (DLNM) based on conditional logistic regression to quantitatively investigate the association of ambient temperature with total and cause-specific CVD mortality, which was used to further estimate mortality burden attributable to non-optimum ambient temperatures.

RESULTS

With adjustment for relative humidity, we observed reverse J-shaped exposure-response associations of ambient temperature with total and cause-specific CVD mortality, with minimum mortality temperatures ranging from 19.5 °C to 23.0 °C. An estimated 20.3% of the total CVD deaths were attributable to non-optimum temperatures, while the attributable fraction (AF) of mortality from chronic rheumatic heart diseases, hypertensive diseases, ischemic heart diseases (IHD), pulmonary heart disease, stroke, and sequelae of stroke was 22.4%, 23.2%, 23.3%, 20.9%, 17.6% and 21.3%, respectively. For total and cause-specific CVDs, most deaths were attributable to moderate cold temperature. We observed significantly higher mortality burden from total and certain cause-specific CVDs in adults 80 years or older and those who were widowed.

CONCLUSION

Exposure to ambient temperature was significantly associated with increased risk of cause-specific CVD mortality. The burden of CVD mortality attributable to non-optimum temperature was substantial especially in older and widowed adults, and significantly varied across specific types of CVD.

Pesticide poisoning risk attributable to ambient temperature: a time series analysis in Qingdao China during 2007-2018

Pesticide poisoning prevention has become a public health issue of great concern. We estimated the association between temperature and attributable risk of pesticide poisoning using 3,545 pesticide poisoning cases in Qingdao China from June 2007 to July 2018. A distributed lag non-linear model was applied to estimate the temperature-pesticide poisoning associated with the assessment of attributable number and fraction. The hot temperature is responsible for the pesticide poisoning incidence, with backward and forward attributable fractions, respectively, 7.79% and 7.61%. Most of the pesticide poisoning burden (backward attributable fraction 5.30% and forward attributable fraction 5.06%) was caused by mild hot (22°C-26°C), whereas the burden due to extreme hot (27°C-31°C) was small (backward attributable fraction 2.94% and forward attributable fraction 2.69%).

Climatic influences on cardiovascular diseases

Classical risk factors only partially account for variations in cardiovascular disease incidence; therefore, also other so far unknown features, among which meteorological factors, may influence heart diseases (mainly coronary heart diseases, but also heart failure, arrhythmias, aortic dissection and stroke) rates. The most studied phenomenon is ambient temperature. The relation between mortality, as well as cardiovascular diseases incidence, and temperature appears graphically as a ‘‘U’’ shape. Exposure to cold, heat and heat waves is associated with an increased risk of acute coronary syndromes. Other climatic variables, such as humidity, atmospheric pressure, sunlight hours, wind strength and direction and rain/snow precipitations have been hypothesized as related to fatal and non-fatal cardiovascular diseases incidence. Main limitation of these studies is the unavailability of data on individual exposure to weather parameters. Effects of weather may vary depending on other factors, such as population disease profile and age structure. Climatic stress may increase direct and indirect risks to human health via different, complex pathophysiological pathways and exogenous and endogenous mechanisms. These data have attracted growing interest because of the recent earth’s climate change, with consequent increasing ambient temperatures and climatic fluctuations. This review evaluates the evidence base for cardiac health consequences of climate conditions, and it also explores potential further implications.

Hourly temperature variability and mortality in 31 major Chinese cities: Effect modification by individual characteristics, season and temperature zone

BACKGROUND

In the context of ongoing climate change, temperature variability (TV) has been considered as an important trigger of death. However, evidence of association between mortality and hourly temperature variability (HTV) is scarce at the multi-city level, and the time window of health effects of HTV is lack of investigation. This study aims at quantifying the mortality risk and burden of HTV and exploring subpopulations susceptible to HTV from a large-scale multi-city perspective.

METHODS

Data on daily number of deaths and meteorology were collected for 31 Chinese major cities during 2007-2013. HTV was calculated as the standard deviation of hourly temperature within a few days. The optimal exposure period of HTV was chosen according to multiple scientific criteria. A quasi-Poisson regression combined with distributed lag nonlinear model was used to assess the city-specific HTV-mortality associations. Then, meta-analysis was further applied to pool city-specific effect estimates. Finally, we calculated the fraction of mortality attributable to HTV. Stratification analyses were conducted by individual characteristics (i.e. age, sex, and educational attainment), season, and region.

RESULTS

HTV calculated in a relatively long-time window like 18 d (HTV_0-17) could capture the impact of HTV adequately. Per 1 °C raise of HTV_0-17 associated with 1.38% (95%CI: 0.77, 1.99) increase of non-accidental mortality. During the study period, 5.47% (95%CI: 1.06, 9.64) of non-accidental mortality could be attributed to HTV. The females, the elderly, and individuals with low education level were more susceptible to HTV than their counterparts, respectively. Moreover, a stronger HTV-mortality association was observed in individuals who live in warmer season and temperature zone.

CONCLUSION

HTV is associated with a considerable mortality burden, which may be modified by season, geographic and individual-level factors. Our findings highlight the practical importance of establishing early warning systems and promoting health education to mitigate the impacts of temperature variability.

Extreme temperature exposure and acute myocardial infarction: Elevated risk within hours?

Day-to-day change in ambient temperature is associated with acute myocardial infarction (AMI) attacks, but evidence is scarce about the effects of extreme temperatures on the risk of AMI within hours of exposure. This study investigated the hour-level associations between extreme temperatures and AMI occurrence. State-wide data on AMI patients and temperature during winter and summer of 2013-2015 were obtained for Queensland state of Australia. We employed a fixed time-stratified case-crossover analysis to quantify the risk of AMI associated with temperature within 24 h after exposure. Subgroups analyses by age, gender and disease history were also conducted. We observed a very acute effect of cold on men (occurred 9-10 h after exposure), women (19-22 h after exposure), and the elderly (4-20 h after exposure). Cold was associated with elevated AMI risk for men within 9 h (OR = 2.1, 95 % CI: 1.2-3.6), women within 19 h (OR = 2.5, 95 % CI: 1.0-6.0), and the elderly within 4 h (OR: 2.0, 95 % CI: 1.0-4.0). However, elevated risk of AMI associated with heat occurred 15 h later for men (OR: 3.9; 95 % CI: 1.1-13.9) and 23 h later for adults (OR: 4.1, 95 % CI: 1.1-15.4). People never suffered AMI and the elderly with diabetes or hyperlipidaemia were particularly vulnerable to cold. Those that were particularly vulnerable to heat were men never experienced AMI or having hypertension or having hyperlipidaemia as well as women ever suffered AMI. Effects of temperature on AMI risk at sub-daily timescales should be considered to prevent cardiac events.

Associations of plasma lipids, lipoproteins, and cardiovascular outcomes with climatic variations in a large Brazilian population of Campinas, São Paulo state: an eight-year study

In this eight-year retrospective study, we evaluated the associations between climatic variations and the biological rhythms in plasma lipids and lipoproteins in a large population of Campinas, São Paulo state, Brazil, as well as temporal changes of outcomes of cardiovascular hospitalizations. Climatic variables were obtained at the Center for Meteorological and Climatic Research Applied to Agriculture (University of Campinas - Unicamp, Brazil). The plasma lipid databases surveyed were from 27,543 individuals who had their lipid profiles assessed at the state university referral hospital in Campinas (Unicamp). The frequency of hospitalizations was obtained from the Brazilian Public Health database (DATASUS). Temporal statistical analyses were performed using the methods Cosinor or Friedman (ARIMA) and the temporal series were compared by cross-correlation functions. In normolipidemic cases (n=11,892), significantly different rhythmicity was observed in low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol (C) both higher in winter and lower in summer. Dyslipidemia (n=15,651) increased the number and amplitude of lipid rhythms: LDL-C and HDL-C were higher in winter and lower in summer, and the opposite occurred with triglycerides. The number of hospitalizations showed maximum and minimum frequencies in winter and in summer, respectively. A coincident rhythmicity was observed of lower temperature and humidity rates with higher plasma LDL-C, and their temporal series were inversely cross-correlated. This study shows for the first time that variations of temperature, humidity, and daylight length were strongly associated with LDL-C and HDL-C seasonality, but moderately to lowly associated with rhythmicity of atherosclerotic outcomes. It also indicates unfavorable cardiovascular-related changes during wintertime.

Modelling of Temperature-Attributable Mortality among the Elderly in Lisbon Metropolitan Area, Portugal: A Contribution to Local Strategy for Effective Prevention Plans

Epidemiological studies on the impact of determining environmental factors on human health have proved that temperature extremes and variability constitute mortality risk factors. However, few studies focus specifically on susceptible individuals living in Portuguese urban areas. This study aimed to estimate and assess the health burden of temperature-attributable mortality among age groups (0-64 years; 65-74 years; 75-84 years; and 85+ years) in Lisbon Metropolitan Area, from 1986-2015. Non-linear and delayed exposure-lag-response relationships between temperature and mortality were fitted with a distributed lag non-linear model (DLNM). In general, the adverse effects of cold and hot temperatures on mortality were greater in the older age groups, presenting a higher risk during the winter season. We found that, for all ages, 10.7% (95% CI: 9.3-12.1%) deaths were attributed to cold temperatures in the winter, and mostly due to moderately cold temperatures, 7.0% (95% CI: 6.2-7.8%), against extremely cold temperatures, 1.4% (95% CI: 0.9-1.8%). When stratified by age, people aged 85+ years were more burdened by cold temperatures (13.8%, 95% CI: 11.5-16.0%). However, for all ages, 5.6% of deaths (95% CI: 2.7-8.4%) can be attributed to hot temperatures. It was observed that the proportion of deaths attributed to exposure to extreme heat is higher than moderate heat. As with cold temperatures, people aged 85+ years are the most vulnerable age group to heat, 8.4% (95% CI: 3.9%, 2.7%), and mostly due to extreme heat, 1.3% (95% CI: 0.8-1.8%). These results provide new evidence on the health burdens associated with alert thresholds, and they can be used in early warning systems and adaptation plans.

Years of life lost and mortality risk attributable to non-optimum temperature in Shenzhen: a time-series study

To assess YLL and mortality burden attributable to non-optimum ambient temperature, we collected mortality and environmental data from June 1, 2012 to December 30, 2017 in Shenzhen. We applied distributed lag nonlinear models with 21 days of lag to examine temperature-YLL and temperature-mortality associations, and calculated the attributable fractions of YLL and deaths for non-optimum temperature, including four subranges, mild cold, mild heat, extreme cold, and extreme heat. Cold and heat were distinguished by the optimum temperature, and each was separated into extreme and mild by cutoffs at 2.5th (12.2 °C) and 97.5th (30.4 °C) temperature percentile further. The optimum temperature was defined as the temperature that had minimum effect on YLL or mortality risk. The optimum temperature for non-accidental YLL was 24.5 °C, and for mortality it was 25.4 °C. Except for the population older than 65 years, the optimum temperature was generally lower in the YLL model than the mortality model. Of the total 61,576 non-accidental deaths and 1,350,835.7 YLL within the study period, 17.28% (95% empirical CI 9.42-25.14%) of YLL and 17.27% (12.70-21.34%) of mortality were attributable to non-optimum temperature. More YLL was caused by cold (10.14%, 3.94-16.36%) than by heat (7.14%, 0.47-13.88%). Mild cold (12.2-24.5 °C) was responsible for far more YLL (8.78%, 3.00-14.61%) than extreme cold (3.5-12.2 °C). As for cardiovascular deaths, only the fractions attributable to overall and cold temperature were significant, with mild cold contributing the largest fraction to YLL (16.31%, 6.85-25.82%) and mortality (16.08%, 9.77-21.22%). Most of the temperature-related YLL and mortality was attributable to mild but non-optimum weather, especially mild cold, while the YLL model implied a more prominent heat effect on premature death. Our findings can supply additional evidence from multiperspectives for health planners to define priorities and make targeted policies for mitigating the burden of adverse temperatures.

Impacts of urbanization on the temperature-cardiovascular mortality relationship in Beijing, China

The effect of temperature on cardiovascular disease (CVD) mortality has been extensively studied. However, it remains largely unknown over whether there is any difference between urban and suburban areas within the same city and how urbanization modifies the relationship between temperature and CVD mortality. In order to examine whether the association between temperature and CVD mortality existed difference in urban and suburban areas, and how urbanization modified this association, we used a distributed lag nonlinear model and a generalized additive model to investigate temperature-related CVD mortality in urban and suburban areas in Beijing, China, from 2006 to 2011. The age, gender, and educational attainment of the population were stratified to explore the modifying effect. We observed that the impacts of heat and cold temperature on CVD mortality were higher in suburban areas than in urban areas. In addition, the elderly and illiterate subjects in suburban areas were more vulnerable to both heat and cold than their counterparts in urban areas. Moreover, higher urbanization levels were significantly associated with districts having lower the excess risks for temperature- CVD mortality. Our findings provide evidence that populations in suburban Beijing have higher risk of temperature-related CVD mortality than those in urban areas. Therefore, greater attention should be paid to vulnerable groups in suburban areas to reduce temperature-related health burden.

Individual sensitivity of cold pressor, environmental meteorological factors associated with blood pressure and its fluctuation

Previous studies have examined the associations of meteorological factors with blood pressure; however, these associations have not fully elucidated, especially lacking of evidence from cohort study, little information about the associations of cold pressor sensitivity with blood pressure and its fluctuation. The objective of this study was to investigate the outdoor and indoor temperature, barometric pressure, humidity, and cold pressor sensitivity with blood pressure and its fluctuation. Forty-eight healthy subjects were recruited, and response of blood pressure to cold exposure was measured with cold pressor test (CPT). Then, all the subjects were followed up, and blood pressure was measured every half a month in a period of consecutive 12 months. Multiple panel analysis with random-effects generalized least squares (GLS) regression was used to analyze the effect of the outdoor and indoor temperature, barometric pressure, humidity, and response to cold pressor exposure on blood pressure. Outdoor and indoor temperature and humidity were found to be independently associated with blood pressure (all the P values < 0.05). The response to cold exposure positively associated with blood pressure and its fluctuation (P < 0.05). The subjects with higher cold pressor sensitivity had about 4.7 mmHg higher maximum difference of SBP in 1 year than the subjects with lower sensitivity. Outdoor and indoor temperature, humidity, and response to cold exposure are associated with blood pressure and its fluctuation. These findings provided extending evidence on blood pressure management in clinic and preventive practice.

Influence of summer tourist flows on occurrence of out-of-hospital cardiac arrest in an Italian tourist-intensive area

INTRODUCTION

The study aims to evaluate the seasonal variation of out-of hospital cardiac arrest (OHCA) in a tourist-intensive area.

METHODS

Data of all OHCA treated by the Emergency Medical Service of Lecce (LE-EMS), Italy, between 2013 and 2017, were retrospectively analyzed and complemented with information about tourist flows, in order to determine the influence of the seasonal variation of population on incidence and outcome.

RESULTS

Tourist arrivals were around 1,700,000 per year, mostly in summer, adding up to 803,161 residents. The occurrence of OHCA did not show a monthly variation when referring to the resident population (p = 0.90). When taking into account the tourist flows, a difference in occurrence of OHCA across months was found, with the highest rate of arrests in December and the lowest in August (10.3 vs 3.4 per 100,000 persons, p < 0.01). No difference was found in terms of EMS arrival time and event survival rate between summer and the rest of the year (13.6 vs 13.8 min, p = 0.55, and 4.4% vs 4.5%, p = 0.86, respectively).

CONCLUSION

In summer tourism areas, the occurrence of OHCA is unchanged throughout the year, while the actual population presents seasonal increases. Summer enhancement of provincial EMS may contribute to maintain the performance of emergency care.

Years of life lost with premature death due to ambient temperatures in a southwest plateau region of China: a cause-specific and individual characteristics stratified mortality study

We aimed to explore whether there were cold and heat temperature adverse effects on years of life lost (YLL) for non-accidental mortality in Yuxi, a southwest plateau region of China. From data for 89,467 non-accidental deaths over an 8-year study period, we used a general linear regression model combined with a distributed lag non-linear model to assess the burden of disease non-accidental mortality due to ambient temperature with the YLL indicator. We estimated the mean YLL change per 1 °C decrease from the 25th to 1st percentile mean temperature as the cold effect and per 1 °C increase from the 75th to 99th percentile as the heat effect. The 95% empirical confidence intervals (eCIs) were calculated by using a bootstrap simulation method. The exposure-response curve between average temperature and YLL was U-shaped. The cold effect peaked at the first day after exposure and disappeared at 2 weeks, and the heat effect only lasted for the first 3 days. A per 1 °C decrease from the 25th to 1st mean temperature percentile was associated with an increase of 15.6 (95% eCI: 2.4, 22.9) in YLL for non-accidental diseases, and the cumulative effects due to cold were stronger in contrast to that attributed by heat. Cold temperature had a significant impact on YLL among the subgroups, with higher YLL in cardiovascular disease, stroke, males, Han nationality, married, and those engaged in agriculture than their corresponding categories. An increasing death burden of non-accidental in Yuxi of China due to cold temperature was demonstrated, and the association was also modified by specific disease causes and individual features.

Temperature modulation of the adverse consequences on human mortality due to exposure to fine particulates: A study of multiple cities in China

Exposure to particulate matter of smaller than 2.5 μm in diameter (PM_2.5) is linked to increased human mortality, and could be further complicated by concurrent ambient air temperatures. Published reports indicate that the association between ambient temperatures and mortality due to PM_2.5 exposure is dissimilar across different geographic areas. Thus, it is unclear how ambient temperatures at different geographic locations can together modulate the influence of PM_2.5 on mortality. In this paper, we examined how temperature modulated the association between mortality and PM_2.5 exposure in 15 Chinese cities during 2014-2016. For analysis, First, Poisson generalized additive models under different temperature stratifications (<10th, 10-90th, and >90th temperature percentiles) was used to estimate PM_2.5 associations to mortality, which were specific to different cities. Second, we used a meta-analysis to combine the effects at each temperature stratum and region (southern and northern China). Results revealed that high temperatures (daily mean temperature >90th percentile) robustly amplified observed associations of mortality and PM_2.5 exposure, and the modifications were heterogeneous geographically. In the northern regions, a 10 μg/m³ increment in PM_2.5 was associated with 0.18%, 0.28%, and 1.54% increase in non-accidental mortalities and 0.33%, 0.39%, and 1.32% increase in cardiovascular mortalities at low, moderate, and high temperature levels, respectively. In the southern regions, a 10 μg/m³ increment in PM_2.5 was associated with 0.52%, 0.62%, and 1.90% increase in non-accidental mortalities and 0.55%, 0.98%, and 2.25% increase in cardiovascular mortalities at low, moderate, and high temperature levels, respectively. It is concluded that temperature altered PM_2.5-mortality associations in southern and northern China synergistically, but the effect was more pronounced in the south. Therefore, geography and temperature need to be considered when studying how PM_2.5 affects health.

Reversal of the seasonality of temperature-attributable mortality from respiratory diseases in Spain

A growing number of epidemiological studies have recently assessed temporal variations in vulnerability and/or mortality attributable to hot and cold temperatures. However, the eventual changes in the seasonal distribution of temperature-attributable mortality remain unexplored. Here, we analyse countrywide daily time-series of temperature and mortality counts from respiratory diseases by sex, age group and province of residence during the period 1980–2016 in Spain. We show the complete reversal of the seasonality of temperature-attributable mortality, with a significant shift of the maximum monthly incidence from winter to summer, and the minimum monthly incidence from early and late summer to winter. The reversal in the seasonal distribution of the attributable deaths is not driven by the observed warming in both winter and summer temperatures, but rather by the very large decrease in the risk of death due to cold temperatures and the relatively much smaller reduction due to hot temperatures. We conclude that the projected decrease in the number of moderate and extreme cold days due to climate warming will not contribute to a further reduction of cold-attributable respiratory deaths.

Potential changes in the seasonality of temperature-attributable mortality due to climate warming have been poorly investigated. Here, the authors show that the projected decrease in the number of moderate and extreme cold days will not contribute to a further reduction of cold-attributable deaths.

Winter temperature and myocardial infarction in Brisbane, Australia: Spatial and temporal analyses

Myocardial infarction (MI) incidence often peaks in winter, but it remains unclear how winter temperature affects MI temporally and spatially. We examined the short-term effects of winter temperature on the risk of MI and explored spatial associations of winter MI hospitalizations with temperature and socioeconomic status (area-based index) in Brisbane, Australia. We used a distributed lag non-linear model to fit the association at the city level between population-weighted daily mean temperature and daily MI hospitalizations during 11 winters of 2005-2015. For each winter, a Bayesian spatial conditional autoregressive model was fitted to examine the associations at postal code level of MI hospitalisations with temperature and socioeconomic status measured as the Index of Relative Socio-Economic Advantage and Disadvantage (IRSAD). Area-specific winter temperature was categorised into three levels: cold (<25th percentile of average winter temperature across postal areas), mild (25th-75th percentile) and warm (>75th percentile). This study included 4978 MI hospitalizations. At the city level, each 1 °C drop in temperature below a threshold of 15.6 °C was associated with a relative risk (RR) of 1.016 (95% confidence interval (CI): 1.008-1.024) for MI hospitalizations on the same day. Low temperature had a much delayed and transient effect on women but an immediate and longer-lasting effect on men. Winter MI incidence rate varied spatially in Brisbane, with a higher incidence rate in warmer areas (RR for mild areas: 1.214, 95%CI: 1.116-1.320; RR for warm areas: 1.251, 95%CI: 1.127-1.389; cold areas as the reference) and in areas with lower socioeconomic levels (RR: 0.900, 95%CI: 0.886-0.914 for each decile increase in IRSAD). This study provides compelling evidence that short-term winter temperature drops were associated with an elevated risk of MI in the subtropical region with a mild winter. Particular attention also needs to be paid to people living in relatively warm and socioeconomically disadvantaged communities in winter.

Some Near- and Far-Environmental Effects on Human Health and Disease with a Focus on the Cardiovascular System

Environmental effects on human physiopathology are revisited herein from a chronobiologic viewpoint, with a focus on the cardiovascular system. Physiological variables undergo recurring changes that are predictable in a statistical, albeit not deterministic way. Biological rhythms cover a broad range of frequencies, which are usually shared by the environment as “co-periodisms”. Some of these photic and non-photic periodicities shared by the environment and physiopathology are reviewed herein, together with their possible underlying mechanisms. A plausible cascade of events from the long-period cycles found in the cosmic environment to those affecting the Earth’s atmosphere and weather conditions is presented, which may shed light on how they may shape the cycles characterizing human health. Maps of important cycles shared between the environment and physiopathology are being catalogued in an atlas of chronomes with the goal of distinguishing between strong and weak associations and providing an estimate of the lag that can be anticipated before observing physiological changes.

The role of cities in reducing the cardiovascular impacts of environmental pollution in low- and middle-income countries

BACKGROUND

As low- and middle-income countries urbanize and industrialize, they must also cope with pollution emitted from diverse sources.

MAIN TEXT

Strong and consistent evidence associates exposure to air pollution and lead with increased risk of cardiovascular disease occurrence and death. Further, increasing evidence, mostly from high-income countries, indicates that exposure to noise and to both high and low temperatures may also increase cardiovascular risk. There is considerably less research on the cardiovascular impacts of environmental conditions in low- and middle-income countries (LMICs), where the levels of pollution are often higher and the types and sources of pollution markedly different from those in higher-income settings. However, as such evidence gathers, actions to reduce exposures to pollution in low- and middle-income countries are warranted, not least because such exposures are very high. Cities, where pollution, populations, and other cardiovascular risk factors are most concentrated, may be best suited to reduce the cardiovascular burden in LMICs by applying environmental standards and policies to mitigate pollution and by implementing interventions that target the most vulnerable. The physical environment of cities can be improved though municipal processes, including infrastructure development, energy and transportation planning, and public health actions. Local regulations can incentivize or inhibit the polluting behaviors of industries and individuals. Environmental monitoring can be combined with public health warning systems and publicly available exposure maps to inform residents of environmental hazards and encourage the adoption of pollution-avoiding behaviors. Targeted individual or neighborhood interventions that identify and treat high-risk populations (e.g., lead mitigation, portable air cleaners, and preventative medications) can also be leveraged in the very near term. Research will play a key role in evaluating whether these approaches achieve their intended benefits, and whether these benefits reach the most vulnerable.

CONCLUSION

Cities in LMICs can play a defining role in global health and cardiovascular disease prevention in the next several decades, as they are well poised to develop innovative, multisectoral approaches to pollution mitigation, while also protecting the most vulnerable.

Heat waves, ambient temperature, and risk of myocardial infarction: an ecological study in the Community of Madrid

INTRODUCTION AND OBJECTIVES

Episodes of extreme heat are associated with increased morbidity and mortality in chronically-ill patients but there is a need to clearly establish the relationship between extreme heat and myocardial infarction. The aim of this study was to analyze the relationship between the incidence of ST-segment elevation myocardial infarction (STEMI) and maximum temperature, in particular during heat wave alert periods (HWAP).

METHODS

The population studied consisted of confirmed STEMI cases registered in the Infarction Code of the Community of Madrid between June 2013 and June 2017. Incidence rate ratios (IRR) adjusted for trend and seasonality and 95%CI were estimated using time series regression models.

RESULTS

A total of 6465 cases of STEMI were included; 212 cases occurred during the 66-day period of HWAP and 1816 cases during the nonalert summer period (IRR, 1.14; 95%CI, 0.96-1.35). The minimum incidence rate was observed at the maximum temperature of 18°C. Warmer temperatures were not associated with a higher incidence (IRR,1.03; 95%CI, 0.76-1.41), whereas colder temperatures were significantly associated with an increased risk (IRR, 1.25; 95%CI, 1.02-1.54). No effect modification was observed by age or sex.

CONCLUSIONS

We did not find an increased risk of STEMI during the 66 days of HWAP in the Community of Madrid between June 2013 and June 2017. However, an increased risk was found during colder temperatures. No extra health resources for STEMI management are required during periods of extreme heat, but should be considered during periods of cold weather.

The hospitalization attributable burden of acute exacerbations of chronic obstructive pulmonary disease due to ambient air pollution in Shijiazhuang, China

Few studies have investigated the acute exacerbations of chronic obstructive pulmonary disease (AECOPD)-associated attributable burden under exposure to high levels of air pollution among Asians. Data on hospitalization for AECOPD, air pollution and meteorological factors from 1 January 2013 to 31 December 2016 were collected in Shijiazhuang, China. We used a Poisson generalized linear regression model combined with a distributed lag nonlinear model (DLNM) to evaluate the relative cumulative risk for a lag of 0-7 days and examined the potential effect modifications by age and sex via stratification analyses, controlling for long-term trends, seasonal patterns, meteorological factors, and other possible confounders. Then, we computed hospitalization percentages attributable to air pollutants. The AECOPD-associated relative cumulative risks for PM_2.5, PM₁₀, NO₂, SO₂, and CO for a lag of 0-7 days were significantly positively correlated with hospitalization. The associations were stronger in females and retired patients. The NO₂ Cum RR of AECOPD admission was the greatest. A 10μg/m³ increase in daily NO₂ concentration was associated with 6.7% and 5.7% increases in COPD hospitalizations in the retired and female groups, respectively. The results showed that 13%, 9.4%, 1.7%, 9.7%, and 8.8% of AECOPD hospitalizations were attributable to exposure to PM_2.5, PM₁₀, SO₂, NO₂, and CO, respectively. If the air pollutant concentration was reduced to the 24-h average grade II levels of NAAQS of China, the AECOPD attributable percentage for PM_2.5 and PM₁₀ would decrease by 80%. The air pollutants PM_2.5, PM₁₀, SO₂, NO₂, and CO were significantly relevant to AECOPD-associated hospitalization. The associations differed by individual characteristics. The retired and female populations were highly vulnerable.

Comparison of air pollutant-related hospitalization burden from AECOPD in Shijiazhuang, China, between heating and non-heating season

Few researches have been investigated on the effects of ambient air pollutants from coal combustion on acute exacerbation of chronic obstructive pulmonary disease (AECOPD) hospitalizations. The whole time series was split into heating season and non-heating season. We used a quasi-Poisson generalized linear regression model combined with distributed lag non-linear models (DLNMs) to estimate the relative cumulative risk and calculate the air pollutant hospitalization burden of AECOPD for lag 0-7 days in heating season and non-heating season. There were higher PM_2.5, PM₁₀, NO₂, SO₂, and CO concentrations in heating seasons than non-heating season in Shijiazhuang; however, O₃ was higher in non-heating season than heating season. The AECOPD-associated relative cumulative risks for PM_2.5, PM₁₀, NO₂, and SO₂ for lag 0-7 days were significantly positively associated with hospitalization in heating and non-heating season; we found that the cumulative relative risk of NO₂ was the greatest in every 1 unit of air pollutants during the heating season and the cumulative relative risk of SO₂ was the greatest during the non-heating season. The results showed that 17.8%, 12.9%, 1.7%, 16.7%, and 10.5% of AECOPD hospitalizations could be attributable to PM_2.5, PM₁₀, SO₂, NO₂, and CO exposure in heating season, respectively. However, the results showed that 19.5%, 22.4%, 15%, 8.3%, and 10.4% of AECOPD hospitalizations could be attributable to PM_2.5, PM₁₀, SO₂, NO_2, and O₃ exposure in non-heating season, respectively. The attributable burden of AECOPD hospitalization in heating season and non-heating season are different. PM_2.5, PM₁₀, NO₂, and CO are the main factors of heating season, while PM₁₀, PM_2.5, SO₂, and O₃ are the main factors of non-heating season. In conclusions, the centralized heating can change the influence of attributable risk. When government departments formulate interventions to reduce the risk of acute hospitalization of chronic obstructive pulmonary disease (COPD), the influence of heating on disease burden should be considered.

Short - term effects of temperature on hospital admissions for acute myocardial infarction: A comparison between two neighboring climate zones in Vietnam

BACKGROUND

Vietnam is one of the countries most affected by climate change, but few studies have focused on the population health effects of climate variation. Extreme heatwaves and cold spells might exacerbate underlying chronic conditions and precipitate hospitalization or early death. This study examined the short-term effects of ambient temperature extremes on hospital admissions (HAs) due to acute myocardial infarction (AMI) between different climate zones in the Central Coast region of Vietnam.

METHODS

Information from medical records of all 3328 cases of AMI HAs (with hospital records cross-checked by clinicians) was collected from three hospitals in the South-Central Coast region (tropical savanna climate) and North-Central Coast region (tropical monsoon climate) for the period 2008-2015. Meteorological data were obtained from the National Hydro-Meteorological and Environment Network Centre. We used distributed lag non-linear models to assess the association between daily average temperature and AMI HAs, accounting for long-term trend and other meteorological variables.

RESULTS

We found a negative and significant association between AMI HAs and temperature in the North-Central Coast region while conversely there was a positive and significant association in the South-Central Coast region. In the North-Central Coast region, the risk of AMI HAs increased by 11% (Relative risk (RR): 1.11, 95% CI: 0.91-1.35, p > 0.05) at moderately low temperatures (10th percentile of temperature range - 18.5 °C) and increased by 25% (RR: 1.25, 95% CI: 1.02-1.55, p < 0.05) at extremely low temperatures (5th percentile of temperature range - 16.8 °C). In the South-Central Coast region, the risk of AMI HAs increased by 18% (RR: 1.18, 95% CI: 0.95-1.47, p > 0.05) and 36% (RR: 1.36, 95% CI: 1.06-1.73, p < 0.05) at moderately high temperatures (90^th percentile of temperature range -29.5 °C) and extreme high temperatures (95th percentile of temperature range - 29.9 °C), respectively.

CONCLUSIONS

Risk of AMI is associated with extremely high and extremely low temperature in Vietnam and the risk varies in relation to the local regional climate. Public health preparedness and multi-level interventions should attempt to reduce people's exposure in periods of disadvantageous temperatures.

The effect and burden modification of heating on adult asthma hospitalizations in Shijiazhuang: a time-series analysis

Background

Previous studies have found associations between asthma morbidity and air pollution especially in young population, (PLoS One 12:e0180522, 2017; Can J Public Health 103:4-8, 2012; Environ Health Perspect 118:449-57, 2010; Am J Respir Crit Care Med 182:307-16, 2010; J Allergy Clin Immunol 104:717-22, 2008; J Allergy Clin Immunol 104:717-22, 1999; Environ Res 111:1137-47, 2011) but most of them were conducted in areas with relatively low air pollutant level. Moreover, very few studies have investigated the effect and burden modification of heating season during which the ambient air pollution level is significantly different from that during non-heating season in north China.

Objectives

This study aimed to evaluate the effect and burden modification of heating on short-term associations between adult asthma hospitalizations and ambient air pollution in the north China city of Shijiazhuang.

Methods

Generalized additive models combined with penalized distributed lag nonlinear models were used to model associations between daily asthma hospitalizations and ambient air pollutants from 1 January 2013 to 16 December 2016 in Shijiazhuang city, adjusting for long-term and seasonality trend, day of week, statutory holiday, daily mean air pressure and temperature. Attributable risks were calculated to evaluate the burden of asthma hospitalizations due to air pollutants exposure. The effect of pollutants on hospitalization and the attributable measures were estimated in heating and non-heating season separately and the comparisons between the two seasons were conducted.

Results

All pollutants demonstrated positive and significant impacts on asthma hospitalizations both in heating season and non-heating season, except for O₃ in heating season where a negative association was observed. However, the differences of the pollutant-specific effects between the two seasons were not significant. SO₂ and NO₂ exposure were associated with the heaviest burden among all pollutants in heating season; meanwhile, PM₁₀ and PM_2.5 were associated with the heaviest burden in heating season.

Conclusions

In conclusion, we found evidence of the effect of ambient air pollutants on asthma hospitalizations in Shijiazhuang. The central heating period could modify the effects in terms of attributable risks. The disease burden modification of heating should be taken into consideration when planning intervention measures to reduce the risk of asthma hospitalization.

Effects of heat on first-ever strokes and the effect modification of atmospheric pressure: A time-series study in Shenzhen, China

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.

Burden of non-accidental mortality attributable to ambient temperatures: a time series study in a high plateau area of southwest China

OBJECTIVE

To examine the total non-accidental mortality burden attributable to ambient temperatures and assess the effect modification of the burden by specific causes of death and individual characteristics in a high plateau area in southwest China.

METHODS

Using daily mortality and meteorological data from 2009 to 2016, we applied a quasi-Poisson model combined with a distributed lag non-linear model to estimate the temperature-mortality association with the assessment of attributable fraction and number. We calculated attributable fractions and deaths with 95% empirical CIs (eCIs), that were due to cold and heat, defined as temperatures below and above the median temperature, and for mild and extreme temperatures, defined by cut-offs at the 2.5th and 97.5th temperature percentiles.

RESULTS

We analysed 89 467 non-accidental deaths; 4131 were attributable to overall temperatures, with an attributable fraction of 4.75% (95% eCI 2.33% to 6.79%). Most of the mortality burden was caused by cold (4.08%; 0.86% to 7.12%), whereas the burden due to heat was low and non-significant (0.67%; -2.44% to 3.64%). Extreme cold (1.17%; 0.58% to 1.69%) was responsible for 24.6% (ie, 1.17% divided by 4.75%) of the total death burden. In the stratification analyses, attributable risk due to cold was higher for cardiovascular than respiratory disease (6.18% vs 3.50%). We found a trend of risk of increased death due to ambient temperatures with increasing age, with attributable fractions of 1.83%, 2.27% and 6.87% for age ≤64, 65-74 and ≥75 years old, respectively. The cold-related burden was slightly greater for females, farmers, ethnic minorities and non-married individuals than their corresponding categories.

CONCLUSIONS

Most of the burden of death was attributable to cold, and specific causes and individual characteristics might modify the mortality burden attributable to ambient temperatures. The results may help make preventive measures to confront climate change for susceptible population in this region.

Seasonal analyses of the association between prenatal ambient air pollution exposure and birth weight for gestational age in Guangzhou, China

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, PM₁₀, NO₂, SO₂, and O₃) 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, NO₂, SO₂, and O₃ 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), NO₂ (12.7 μg/m³), SO₂ (2.8 μg/m³) and O₃ (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, PM₁₀, SO₂, and O₃ 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.

Projections for temperature-related years of life lost from cardiovascular diseases in the elderly in a Chinese city with typical subtropical climate

OBJECTIVE

Extreme temperature is an important risk factor for cardiovascular diseases, and the elderly are particularly vulnerable to temperature variation. Global warming and the increasingly aging population are two major global challenges for human health; thus, an urgent need exists to project the temperature-related cardiovascular disease burden regarding both of the aforementioned factors. We aimed to the project temperature-related burden of cardiovascular diseases using years of life lost (YLL) in the elderly in a Chinese city with typical subtropical climate.

METHODS

A retrospective time-series study was first conducted to estimate cardiovascular disease burden associated with temperature in the elderly from 2008 to 2015 in Ningbo, China. Then, future projections considering demographic change and adaptation under 19 global-scale climate models (GCMs) and 3 different Representative Concentration Pathways (RCPs) scenarios for the 2050s and 2070s were estimated.

RESULTS

The exposure-response curve for temperature on YLL from cardiovascular diseases was U-shaped, with increased YLL for both higher- and lower- than optimal temperature. The projected annual increase in heat-related YLL was outweighed by the decrease in cold-related YLL. However, monthly analysis demonstrated that temperature-related YLL will increase significantly in August. Additionally, heat-related YLL is projected to increase 3.1-11.5 times for the 2050s and 2070s relative to baseline, when considering demographic changes, even with 30% adaptation taken into consideration.

CONCLUSIONS

Although annual YLL from cardiovascular diseases in the elderly associated with temperature will decrease in the future, heat-related YLL will increase tremendously, which indicates that more adaptation strategies and greenhouse emission control measures should be undertaken to reduce the future heat-related burden of cardiovascular diseases in the elderly.

Future temperature-related years of life lost projections for cardiovascular disease in Tianjin, China

It is widely accepted that temperatures is associated with cardiovascular mortality, however, few studies have explored the effects of temperature on years of life lost (YLL) from cardiovascular mortality in China under future global warming scenarios. Therefore, there is an urgent need to obtain projections of YLL from cardiovascular diseases. Here we applied nineteen global-scale climate models (GCMs) and three Representative Concentration Pathway emission scenarios (RCPs) in the 2050s and 2070s for temperature-related YLL projection in Tianjin, China. We found the relationships between daily maximum temperatures with YLL from cardiovascular mortality were basically U-shaped. We observed increasing net annual YLL across a range of multiple models under different climate scenarios, suggesting that increasing heat-related YLL from cardiovascular mortality could offset decreasing cold-related YLL from cardiovascular mortality. The largest temperature-related YLL from cardiovascular mortality were observed under the RCP8.5 scenario and increased more rapidly in the 2070s versus the 2050s. Monthly analyses of percent changes in YLL from cardiovascular mortality showed that the largest percent increases occurred from May to September. If warm adaptation occurs, only the adverse effects under RCP2.6 could be fully offset in both 2050 and 2070. Our exploration provided further evidence for the potential health impacts of global warming and highlighted that government should develop environmental policies for future health risks.

Temporal and seasonal variations of mortality burden associated with hourly temperature variability: A nationwide investigation in England and Wales

BACKGROUND

Sudden temperature change may elevate short-term mortality and remains an important global health threat in the context of climate change. To date, however, little available temperature-mortality evidence has taken into account both intra- and inter-day temperature variability (TV), thus largely limiting the comprehensive understanding of mortality burden due to unstable weather. Moreover, seasonal and temporal patterns in TV-mortality associations were sparsely discussed, nationally and regionally.

OBJECTIVES

We aimed to assess the nationwide association of all-cause mortality with hourly temperature variability (HTV), quantify HTV-attributable mortality, and further explore the temporal and seasonal variations of mortality burden due to HTV in United Kingdom.

METHODS

Fourteen-year time-series data on temperature and mortality were collected from 10 regions in England and Wales during 1993-2006, totally including 7,573,716 all-cause deaths. HTV was calculated from the standard deviation of hourly temperature records within two neighboring days. A three-stage analytic approach was adopted to assess HTV-associated mortality burden. We first applied a time-series quasi-Poisson regression to estimate region-specific HTV-mortality associations, then pooled these associations at the national level using a multivariate meta-analysis, and finally estimated the HTV-attributable mortality fraction and illustrated its seasonal and temporal variations by conducting season- and period-specific analyses based on time-varying distributed lag models.

RESULTS

We found strong evidence that large HTV exposure elevated short-term mortality risk in England and Wales, with a pooled estimate of 1.13% (95% confidence interval (CI): 0.88, 1.39) associated with a 1-°C increase in HTV. During the whole study period, HTV accounted for a national average attributable fraction of 2.52% (95% empirical confidence interval (eCI): 2.27, 2.76) of the total deaths. This HTV-attributable mortality estimate showed a significant temporal decrease (p < 0.001) from 2.72% (95% eCI: 2.58, 2.87) in 1993-99 to 2.28% (95% eCI: 2.13, 2.43) in 2000-06. Additionally, clear seasonal variations were observed for HTV-attributable mortality burden, with the largest estimate of 3.08% (95% eCI: 2.80, 3.38) in summer, followed by 2.71% (95% eCI: 2.44, 2.98) in spring, 2.40% (95% eCI: 2.16, 2.63) in autumn, and 2.00% (95% eCI: 1.81, 2.20) in winter.

CONCLUSIONS

Despite clear evidence observed for the reduction, mortality burden caused by temperature variability remained a great public health threat, especially in warm seasons. It highlighted the importance of specific interventions targeted to unstable weather as well as temperature extremes, so as to reduce climate-related mortality burden.

Effects of diurnal temperature range on mortality in Hefei city, China

Although several studies indicated an association between diurnal temperature range (DTR) and mortality, the results about modifiers are inconsistent, and few studies were conducted in developing inland country. This study aims to evaluate the effects of DTR on cause-specific mortality and whether season, gender, or age might modify any association in Hefei city, China, during 2007-2016. Quasi-Poisson generalized linear regression models combined with a distributed lag non-linear model (DLNM) were applied to evaluate the relationships between DTR and non-accidental, cardiovascular, and respiratory mortality. We observed a J-shaped relationship between DTR and cause-specific mortality. With a DTR of 8.3 °C as the reference, the cumulative effects of extremely high DTR were significantly higher for all types of mortality than effects of lower or moderate DTR in full year. When stratified by season, extremely high DTR in spring had a greater impact on all cause-specific mortality than other three seasons. Male and the elderly (≥ 65 years) were consistently more susceptible to extremely high DTR effect than female and the youth (< 65 years) for non-accidental and cardiovascular mortality. To the contrary, female and the youth were more susceptible to extremely high DTR effect than male and the elderly for respiratory morality. The study suggests that extremely high DTR is a potential trigger for non-accidental mortality in Hefei city, China. Our findings also highlight the importance of protecting susceptible groups from extremely high DTR especially in the spring.

Air pollutants and atmospheric pressure increased risk of ED visit for spontaneous pneumothorax

OBJECTIVE

To investigate the impact of short-term exposure to air pollutants and meteorological variation on ED visits for primary spontaneous pneumothorax (PSP).

MATERIAL AND METHODS

We retrospectively identified PSP cases that presented at the ED of our tertiary center between January 2015 and September 2016. We classified the days into three types: no PSP day (0 case/day), sporadic days (1-2 cases/day), and cluster days (PSP, ≥3 cases/day). Association between the daily incidence of PSP with air pollutants and meteorological data were determined using Poisson generalized-linear-model to calculate incidence rate ratio (IRRs) and the use of time-series (lag-1 [the cumulative air pollution level on the previous day of PSP], lag-2 [two days ago], and lag-3 [three days ago]).

RESULTS

Using multivariate logistic regression analysis, O₃ (p = 0.010), NO₂ (p = 0.047), particulate matters (PM)₁₀ (p = 0.021), and PM_2.5 (p = 0.008) were significant factors of PSP occurrence. When the concentration of O₃, NO₂, PM₁₀, and PM_2.5 were increased, PSP IRRs increased approximately 15, 16, 3, and 5-fold, respectively. With the time-series analyses, atmospheric pressure in lag-3 was significantly lower and in lag-2, was significantly higher in PSP days compared with no PSP days. Among air pollutant concentrations, O₃ in lag-1 (p = 0.017) and lag-2 (p = 0.038), NO₂ in lag-1 (p = 0.015) and lag-2 (p = 0.009), PM₁₀ in lag-1 (p = 0.012), and PM_2.5 in lag-1 (p = 0.021) and lag-2 (p = 0.032) were significantly different between no PSP and PSP days.

CONCLUSION

Increased concentrations of air pollutants and abrupt change in atmospheric pressure were significantly associated with increased IRR of PSP.

Obesity mediated the association of exposure to polycyclic aromatic hydrocarbon with risk of cardiovascular events

Exposure to polycyclic aromatic hydrocarbons (PAHs) could cause high blood pressure (BP) and increased risk for atherosclerotic cardiovascular disease (ASCVD). However, the mechanisms underlying the relationship between them were unclear. We investigated potential mediation effect of obesity on the association of exposure to PAHs with high BP and increased risk for ASCVD. In the repeated measures study, 106 community-dwelling residents in Wuhan, China finished the physical examination in the winter and summer seasons, eight urinary PAHs metabolites were measured. Associations of urinary PAHs with high BP and increased risk for ASCVD were assessed using either linear mixed effect models or generalized estimating equations models. Mediation analysis was performed to evaluate the mediating effect of obesity on the association of urinary PAHs metabolites with high BP or increased risk of ASCVD. We observed the positive association between urinary PAHs metabolites and BP or the odds ratios for high BP (all P<0.05). Additionally, each one-unit increase in ln-transformed urinary levels of 4-hydroxyphenanthrene or the total of PAH metabolites was associated with a 12.63% or 11.91% increase in the estimated 10-year ASCVD risk (both P<0.05). The waist-to-height ratio mediated 29.0% of the association of urinary 4-hydroxyphenanthrene with increased risk of ASCVD (P<0.05). The findings suggest that PAHs exposure may be associated with elevated BP and an increased risk of ASCVD. Obesity may partially mediate the association between PAHs exposure and higher BP or increased risk of ASCVD.

Humidity May Modify the Relationship between Temperature and Cardiovascular Mortality in Zhejiang Province, China

Background: The evidence of increased mortality attributable to extreme temperatures is widely characterized in climate-health studies. However, few of these studies have examined the role of humidity on temperature-mortality association. We investigated the joint effect between temperature and humidity on cardiovascular disease (CVD) mortality in Zhejiang Province, China. Methods: We collected data on daily meteorological and CVD mortality from 11 cities in Zhejiang Province during 2010–2013. We first applied time-series Poisson regression analysis within the framework of distributed lag non-linear models to estimate the city-specific effect of temperature and humidity on CVD mortality, after controlling for temporal trends and potential confounding variables. We then applied a multivariate meta-analytical model to pool the effect estimates in the 11 cities to generate an overall provincial estimate. The joint effects between them were calculated by the attributable fraction (AF). The analyses were further stratified by gender, age group, education level, and location of cities. Results: In total, 120,544 CVD deaths were recorded in this study. The mean values of temperature and humidity were 17.6 °C and 72.3%. The joint effect between low temperature and high humidity had the greatest impact on the CVD death burden over a lag of 0–21 days with a significant AF of 31.36% (95% eCI: 14.79–38.41%), while in a condition of low temperature and low humidity with a significant AF of 16.74% (95% eCI: 0.89, 24.44). The AFs were higher at low temperature and high humidity in different subgroups. When considering the levels of humidity, the AFs were significant at low temperature and high humidity for males, youth, those with a low level of education, and coastal area people. Conclusions: The combination of low temperature and high humidity had the greatest impact on the CVD death burden in Zhejiang Province. This evidence has important implications for developing CVD interventions.