Does the meteorological origin of heat waves influence their impact on health? A 6-year morbidity and mortality study in Madrid (Spain)

Human adaptation to heat in the context of climate change: A conceptual framework

Climate change is causing serious damage to natural and social systems, as well as having an impact on human health. Among the direct effects of climate change is the rise in global surface temperatures and the increase in the frequency, duration, intensity and severity of heat waves. In addition, understanding of the adaptation process of the exposed population remains limited, posing a challenge in accurately estimating heat-related morbidity and mortality. In this context, this study seeks to establish a conceptual framework that would make it easier to understand and organise knowledge about human adaptation to heat and the factors that may influence this process. An inductive approach based on grounded theory was used, through the analysis of case studies connecting concepts. The proposed conceptual framework is made up of five components (climate change, vulnerability, health risks of heat, axes of inequality and health outcomes), three heat-adaptation domains (physiological, cultural and political), two levels (individual and social), and the pre-existing before a heat event. The application of this conceptual framework facilitates the assistance of decision-makers in planning and implementing effective adaptation measures. Recognizing the importance of addressing heat adaptation as a health problem that calls for political solutions and social changes. Accordingly, this requires a multidisciplinary approach that would foster the participation and collaboration of multiple actors for the purpose of proposing effective measures to address the health impact of the rise in temperature.

Short-term impact of extreme temperatures, relative humidity and air pollution on emergency hospital admissions due to kidney disease and kidney-related conditions in the Greater Madrid area (Spain)

While some studies report a possible association between heat waves and kidney disease and kidney-related conditions, there still is no consistent scientific consensus on the matter or on the role played by other variables, such as air pollution and relative humidity. Ecological retrospective time series study 01-01-2013 to 31-12-2018). Dependent variables: daily emergency hospitalisations due to kidney disease (KD), acute kidney injury (AKI), lithiasis (L), dysnatraemia (DY) and hypovolaemia (HPV). Independent variables: maximum and minimum daily temperature (Tmax, Tmin, °C), and daily relative humidity (RH, %). Other variables were also calculated, such as the daily temperature for risk of kidney disease (Theat, °C) and low daily hazardous relative humidity (HRH%). As variables of air pollution, we used the daily mean concentrations of PM10, PM2.5, NO2 and O3 in μg/m3. Based on these, we then calculated their daily excesses over World Health Organisation (WHO) guideline levels (hPM10, hPM2.5, hNO2 and hO3 respectively). Poisson family generalised linear models (GLMs) (link = log) were used to calculate relative risks (RRs), and attributable risks and attributable admissions. In the models, we controlled for the covariates included: seasonalities, trend, autoregressive component, day of the week, month and year. A statistically significant association was found between Theat and all the dependent variables analysed. The greatest AKI disease burden was attributable to Theat (2.2 % (1.7, 2.6) of attributable hospital admissions), followed by hNO2 (1.7 % (0.9, 3.4)) and HRH (0.8 (0.6, 1.1)). In the case of hypovolaemia and dysnatraemia, the greatest disease burden again corresponded to Theat, with 6.9 % (6.2, 7.6) and 5.7 (4.8, 6.6) of attributable hospital admissions respectively. Episodes of extreme heat exacerbate daily emergency hospital admissions due to kidney disease and kidney-related conditions; and attributable risks are likewise seen for low relative humidity and high ozone levels.

Do heat waves worsen air quality? A 21-year observational study in Seoul, South Korea

Heat waves are generally known to deteriorate air quality. However, the impacts of heat waves on air quality can substantially vary depending on characteristics of heat waves. In this study, we examine air quality changes in Seoul during heat waves and their associations with large-scale atmospheric patterns. For this, air quality data from 25 stations and meteorological data from 23 weather stations and reanalysis datasets during July and August of 2001-2021 are used. Under heat waves, the mean daily PM₁₀, NO₂, and CO concentrations decrease by 7.9 %, 6.1 %, and 4.6 %, respectively, whereas the mean daily PM_2.5, O₃, and SO₂ concentrations increase by 4.1 %, 17.2 %, and 2.9 %, respectively. The atmospheric circulation under heat waves is less favorable for long-range transport of air pollutants to Seoul. The PM_2.5/PM₁₀ ratio increases under heat waves, indicating that the secondary formation of aerosols becomes more important under heat waves. 37 % of the heat wave days are accompanied by severe O₃ pollution exceeding the O₃ concentration standard in South Korea. There is a significant variability of air quality in Seoul within heat waves. The heat wave days with higher concentrations of PM_2.5, PM₁₀, O₃, NO₂, and CO than their non-heat wave means exhibit a prominent difference in large-scale atmospheric pattern from the heat wave days with lower concentrations. This difference is characterized by a zonal wave-like pattern of geopotential height, which is similar to the circumglobal teleconnection pattern known as one of the major patterns for heat waves in South Korea. This zonal wave-like pattern produces more stagnant conditions over Seoul.

Analysis of the relationship between ambient air pollution and the severity of heart failure decompensations in two Spanish metropolises (Barcelona and Madrid)

OBJECTIVES

To analyze whether the high levels of air pollutants are related to a greater severity of decompensated heart failure (HF).

METHOD

Patients diagnosed with decompensated HF in the emergency department of 4 hospitals in Barcelona and 3 in Madrid were included. Clinical data (age, sex, comorbidities, baseline functional status), atmospheric (temperature, atmospheric pressure) and pollutant data (SO₂, NO₂, CO, O₃, PM₁₀, PM_2.5) were collected in the city on the day of emergency care. The severity of decompensation was estimated using 7-day mortality (primary indicator) and the need for hospitalization, in-hospital mortality, and prolonged hospitalization (secondary indicators). The association adjusted for clinical, atmospheric and city data between pollutant concentration and severity was investigated using linear regression (linearity assumption) and restricted cubic spline curves (no linearity assumption).

RESULTS

A total of 5292 decompensations were included, with a median age of 83 years (IQR=76-88) and 56% women. The medians (IQR) of the daily pollutant averages were: SO₂=2.5μg/m³ (1.4-7.0), NO₂=43μg/m³ (34-57), CO=0.48mg/m³ (0.35-0.63), O₃=35μg/m³ (25-48), PM₁₀=22μg/m³ (15-31) and PM_2.5=12μg/m³ (8-17). Mortality at 7 days was 3.9%, and hospitalization, in-hospital mortality, and prolonged hospitalization were 78.9, 6.9, and 47.5%, respectively. SO₂ was the only pollutant that showed a linear association with the severity of decompensation, since each unit of increase implied an OR for the need for hospitalization of 1.04 (95% CI 1.01-1.08). The restricted cubic spline curves study also did not show clear associations between pollutants and severity, except for SO₂ and hospitalization, with OR of 1.55 (95% CI 1.01-2.36) and 2.71 (95% CI 1.13-6.49) for concentrations of 15 and 24μg/m³, respectively, in relation to a reference concentration of 5μg/m³.

CONCLUSION

Exposure to ambient air pollutants, in a medium to low concentration range, is generally not related to the severity of HF decompensations, and only NO₂ may be associated with an increased need for hospitalization.