Current and future temperature-related mortality and morbidity in the UK: a public health and climate change perspective

Lead Research Organisation: London School of Hygiene & Tropical Medicine
Department Name: Public Health and Policy

Abstract

Several scientific studies have demonstrated that exposure to extreme outdoor temperatures increases the risk of mortality and morbidity. The interest in this risk factor has grown considerably in the last few years, with the mounting evidence that climate change will increase the frequency and intensity of extreme weather episodes, and consequently the associated health impacts. Governments and international health organisations are under pressure to respond, primarily through the implementation of effective public health and climate policies, which must be based on solid scientific assessments. However, our knowledge on how non-optimal temperature affect human health, and how these risks will change in a warming planet, is still limited.
This project will address these gaps by offering a comprehensive assessment of current and future health risks associated to non-optimal outdoor temperature and climate change in the England and Wales. The research proposal is structured in a detailed plan of four work packages (WPs). In the first WP, the research team will link country-wide health databases with high-resolution environmental measures, and will then apply advanced epidemiological methods to study how exposure to heat and cold increase the risk of mortality and hospital admissions. The evaluation will be extended in WP2 to assess through meta-regression and machine learning methods how the risk varies across small geographical areas and time, and to define differential vulnerability levels of the population in terms of contextual characteristics, such as local climate, socio-economic conditions, infrastructure, and urban settings. This information will be used in WP3 to quantify excess mortality and morbidity at small-area level in the last 35 years, and then to project health impacts under future scenarios that account for several changes, such as trends in global warming, socio-economic pathways, and potential public health policies. The last WP will create repositories to store the full set of results from the project, and will develop easy-to-use web tools to extract, summarise, display, and map risk measures, and to perform scenario simulations. These resources will be released for free and in open-access form, and will be made available to a broad range of users including scientists, public health experts, journalists, and the general public.
The project will provide a detailed picture of health risks associated to heat and cold, and will help identify drivers of vulnerability and resilience within the population of England and Wales. This information is critical to perform an evidence-based quantification of potential benefits related to climate and public health policies, and to compare alternative mitigation and adaptation strategies to reduce the health burden of global warming at national and international level.

Technical Summary

This project will provide a comprehensive evaluation of current and future health risks associated to non-optimal outdoor temperature in England and Wales, by assessing excess mortality and morbidity at small-area level and then projecting impacts under scenarios that account for climate change, socio-economic and demographic trends, and adaptive strategies. The research proposal is structured in a detailed plan of four work packages (WPs).
In the first WP, the research team will link country-wide databases of mortality and hospital admissions with high-resolution environmental measures, and will then apply advanced epidemiological designs to obtain estimate of potentially complex temperature-health associations varying across small administrative areas. The evaluation will be extended in WP2 to assess geographical and temporal differences in risks, applying cutting-edge meta-regression and machine learning models to characterise vulnerability patterns in terms of climatological, socio-economic, infrastructural, and urban setting characteristics. This information will be used in WP3 to quantify excess mortality and morbidity at small-area level in the historical period, and then to project health impacts under composite scenarios of global warming, socio-economic pathways, and potential public health policies. The last WP will create open-access documented repositories and easy-to-use web tools to extract, summarise, and display risk measures, and to perform scenario simulations.
The project will provide a detailed picture of health risks associated to heat and cold, and will help identify drivers of vulnerability and resilience within the population of England and Wales. This information is critical to perform evidence-based assessments of potential benefits related to climate and public health policies, and to compare alternative mitigation and adaptation strategies to reduce the health burden of global warming at national and international level.

Publications

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Hundessa S (2024) Global and Regional Cardiovascular Mortality Attributable to Nonoptimal Temperatures Over Time. in Journal of the American College of Cardiology

 
Title Temperature-related mortality exposure-response functions for 854 cities in Europe 
Description This repository contains data to reconstruct the exposure-response functions (ERF) of temperature-related mortality by five 5 age groups in 854 cities in Europe. These ERFs have been derived in the study by Masselot et al. 2023, Excess mortality attributed to heat and cold: a health impact assessment study in 854 cities in Europe, The Lancet Planetary Health (https://doi.org/10.1016/S2542-5196(23)00023-2). An associated semi-replicable GitHub repository is available at https://github.com/PierreMasselot/Paper--2023--LancetPH--EUcityTRM to reproduce part of the analysis and the full results, as well as to provide technical details on the derivation of these ERFs. Note: This updated version contains revised data after the correction of an error in the code related to the computation of the age-specific baseline mortality rates. Details about the error can be found in the GitHub repository linked above. This correction only affects the figures of excess mortality (found in the `results.zip` archive) while the ERFs are negligibly affected. The originally published results can be found in V1.0.0 of this repository. Extraction of the ERFs The ERFs are provided as coefficients of B-spline functions that can be used to reconstruct the ERFs, along with variance-covariance matrices and quantiles from location-specific temperature distributions. The parametrisation associated with these coefficients is a quadratic B-spline (degree 2), with knots located at the 10th, 75th and 90th percentiles of the temperature distribution. In R, the associated basis can be constructed using the dlnm package, with a temperature series x, as follows: library(dlnm)  basis <- onebasis(x, fun = "bs", degree = 2, knots = quantile(x, c(.1, .75, .9))) The main files associated with ERFs are the following: coefs.csv: The B-spline coefficients for each age group and city. vcov.csv: The variance-covariance matrix of the coefficients in each city and age group. It is provided here as the lower triangular part of the matrix with names indicating the position of each value (v[row][column]). In R, assuming x is a row of this file, the matrix can be reconstructed using xpndMat(x) after loading the mixmeta package. coef_simu.csv: 1000 simulations from the distribution of each city and age-specific coefficients. Useful to derive empirical confidence intervals for derived measures such as excess deaths or attributable fractions. tmean_distribution.csv: The city-specific temperature percentiles representing the distribution of the data derived from the ERA5-Land dataset. Health impact assessment results results.zip: A summary of the results from the health impact assessment reported in the analysis. The dataset includes several impact measures provided in files representing different geographical levels, including city, country and regional level. Different files are also provided for age-group specific or all age results. Additional data We provide additional data that are useful to reproduce or extend the analysis. Please note that due to restrictive data-sharing agreements for the mortality series, only a part of the code is reproducible. See the associated GitHub repository for more details. metadata.csv: City-specific metadata used to create the ERFs and perform the health impact assessment. additional_data.zip: contains further data used to replicate the second stage of the analysis and the final health impact assessment. It includes the full city-level daily temperature series (era5series.csv), the detail of extracted metadata for available years (metacityyear.csv), a description of the city-level characteristics (metadesc.csv), and the first-stage ERF coefficients for all available city and age-groups (stage1res.csv). Additionally, the file meta-model.RData contains R object defining the second-stage model that can be used to predict new ERFs. 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
URL https://zenodo.org/doi/10.5281/zenodo.7672107