Evaluating Mortality Response Associated with Two Different Nordic Heat Warning Systems in Riga, Latvia

Heatwave Definition and Impact on Cardiovascular Health: A Systematic Review

Objectives: We aimed to analyze recent literature on heat effects on cardiovascular morbidity and mortality, focusing on the adopted heat definitions and their eventual impact on the results of the analysis. Methods: The search was performed on PubMed, ScienceDirect, and Scopus databases: 54 articles, published between January 2018 and September 2022, were selected as relevant. Results: In total, 21 different combinations of criteria were found for defining heat, 12 of which were based on air temperature, while the others combined it with other meteorological factors. By a simulation study, we showed how such complex indices could result in different values at reference conditions depending on temperature. Heat thresholds, mostly set using percentile or absolute values of the index, were applied to compare the risk of a cardiovascular health event in heat days with the respective risk in non-heat days. The larger threshold's deviation from the mean annual temperature, as well as higher temperature thresholds within the same study location, led to stronger negative effects. Conclusion: To better analyze trends in the characteristics of heatwaves, and their impact on cardiovascular health, an international harmonization effort to define a common standard is recommendable.

Temperature effects on incidence of surgery for acute type A aortic dissection in the Nordics

We aimed to investigate a hypothesised association between daily mean temperature and the risk of surgery for acute type A aortic dissection (ATAAD). For the period of 1 January 2005 until 31 December 2019, we collected daily data on mean temperatures and date of 2995 operations for ATAAD at 10 Nordic cities included in the Nordic Consortium for Acute Type A Aortic Dissection (NORCAAD) collaboration. Using a two-stage time-series approach, we investigated the association between hot and cold temperatures relative to the optimal temperature and the rate of ATAAD repair in the selected cities. The relative risks (RRs) of cold temperatures (≤-5°C) and hot temperatures (≥21°C) compared to optimal temperature were 1.47 (95% CI: 0.72-2.99) and 1.43 (95% CI: 0.67-3.08), respectively. In line with previous studies, we observed increased risk at cold and hot temperatures. However, the observed associations were not statistically significant, thus only providing weak evidence of an association.

The influence of heat and cold waves on mortality in Russian subarctic cities with varying climates

Publications on ambient temperature-related mortality among Arctic or subarctic populations are extremely rare. While circumpolar areas cover large portions of several European countries, Canada, and the USA, the population of these territories is relatively small, and the data needed for statistical analysis of the health impacts of extreme temperature events are frequently insufficient. This study utilizes standard time series regression techniques to estimate relative increases in cause- and age-specific daily mortality rates during heat waves and cold spells in four Russian cities with a subarctic climate. The statistical significance of the obtained effect estimates tends to be greater in the continental climate than in the marine climate. A small meta-analysis was built around the obtained site-specific health effects. The effects were homogeneous and calculated for the selected weather-dependent health outcomes. The relative risks of mortality due to ischemic heart disease, all diseases of the circulatory system, and all non-accidental causes during cold spells in the age group ≥ 65 years were 1.20 (95% CI: 1.11-1.29), 1.14 (1.08-1.20), and 1.12 (1.07-1.17), respectively. Cold spells were more harmful to the health of the residents of Murmansk, Archangelsk, and Magadan than heat waves, and only in Yakutsk, heat waves were more dangerous. The results of this study can help the public health authorities develop specific measures for the prevention of excess deaths during cold spells and heat waves in the exposed subarctic populations.

Combined Effect of Hot Weather and Outdoor Air Pollution on Respiratory Health: Literature Review

Association between short-term exposure to ambient air pollution and respiratory health is well documented. At the same time, it is widely known that extreme weather events intrinsically exacerbate air pollution impact. Particularly, hot weather and extreme temperatures during heat waves (HW) significantly affect human health, increasing risks of respiratory mortality and morbidity. Concurrently, a synergistic effect of air pollution and high temperatures can be combined with weather–air pollution interaction during wildfires. The purpose of the current review is to summarize literature on interplay of hot weather, air pollution, and respiratory health consequences worldwide, with the ultimate goal of identifying the most dangerous pollution agents and vulnerable population groups. A literature search was conducted using electronic databases Web of Science, Pubmed, Science Direct, and Scopus, focusing only on peer-reviewed journal articles published in English from 2000 to 2021. The main findings demonstrate that the increased level of PM10 and O3 results in significantly higher rates of respiratory and cardiopulmonary mortality. Increments in PM2.5 and PM10, O3, CO, and NO2 concentrations during high temperature episodes are dramatically associated with higher admissions to hospital in patients with chronic obstructive pulmonary disease, daily hospital emergency transports for asthma, acute and chronic bronchitis, and premature mortality caused by respiratory disease. Excessive respiratory health risk is more pronounced in elderly cohorts and small children. Both heat waves and outdoor air pollution are synergistically linked and are expected to be more serious in the future due to greater climate instability, being a crucial threat to global public health that requires the responsible involvement of researchers at all levels. Sustainable urban planning and smart city design could significantly reduce both urban heat islands effect and air pollution.

Mortality attributable to heat and cold among the elderly in Sofia, Bulgaria

Although a number of epidemiological studies have examined the effects of non-optimal temperatures on mortality in Europe, evidence about the mortality risks associated with exposures to hot and cold temperatures in Bulgaria is scarce. This study provides evidence about mortality attributable to non-optimal temperatures in adults aged 65 and over in Sofia, Bulgaria, between 2000 and 2017. We quantified the relationship between the daily mean temperature and mortality in the total elderly adult population aged 65 and over, among males and females aged 65 and over, as well as individuals aged 65-84 and 85 years or older. We used a distributed lag non-linear model with a 25-day lag to fully capture the effects of both cold and hot temperatures and calculated the fractions of mortality attributable to mild and extreme hot and cold temperatures. Cold temperatures had a greater impact on mortality than hot temperatures during the studied period. Most of the temperature-attributable mortality was due to moderate cold, followed by moderate heat, extreme cold, and extreme heat. The total mortality attributable to non-optimal temperatures was greater among females compared to males and among individuals aged 85 and over compared to those aged 65 to 84. The findings of this study can serve as a foundation for future research and policy development aimed at characterizing and reducing the risks from temperature exposures among vulnerable populations in the country, climate adaptation planning and improved public health preparedness, and response to non-optimal temperatures.