Programme d'impulsion

HOT-SPOT

Hospitalizations and Overheating Trends – Studying Public health Outcomes in a Transitioning climate

| Overview

Duration: 36 months
Budget: 150 208 euros

Scientific coordination:
Bénédicte Jacquemin, Noémie Letellier, Elixir Team, U1085 Inserm, IRSET

Partner:
Tarik Benmarhnia, University of California, San Diego

| Context

Heat-related health impacts have drastically increased in the last two decades in France and will grow at a rapid pace in the coming years under climate change with important environmental justice implications. Short-term effects of exposure to extreme heat on morbidities have been largely described in epidemiological literature.

However, there have been no comprehensive investigations of fine-scale relationships between heat and various cause-specific morbidity outcomes, the role of human-induced climate change in such relationships, and health inequities related to heat.

| Aims

We aim to characterize the fine-scale vulnerability and health impacts of heat over space in France. We have three specific aims:

  • To estimate the impacts of heat on hospitalizations for a large set of medical conditions at the commune-level (2006-2020)
  • To quantify the role of anthropogenic climate change in the burden of heat in the past (1990-2020) and projecting future (2030 – 2100)
  • To determine how heat-related health impacts are associated with contextual socioeconomic status as well as historical CO2 emissions level

| Methods

We will use the French administrative healthcare database (Système National des Données de Santé, SNDS), which covers approximately 99% of the French population. We will analyze daily cause-specific hospitalization rates by principal discharge diagnosis codes. We will assess daily average maximum, minimum, and diurnal ambient temperatures for each French commune, provided by the French national meteorological service Météo-France.
First, we will estimate the concentration-response functions (CRF) at the commune-level between multiple heat metrics and hospitalizations for a large set of medical conditions and quantify the burden attributable to heat (2006-2020) by conducting a two-stage time-series approach. We will also assess the spatial distribution of heat-related health impacts using novel spatio-temporal techniques (i.e., a within-community matched design coupled with a Bayesian Hierarchical model).
Second, using the latest climate simulations (Coupled Model Intercomparison Projects [CMIP6] downscaled and bias-corrected products), and relying on the CRF developed before, we will use a health impact assessment approach to first estimate the future burden in the context of climate change the upcoming decades (horizon 2030-2100) at the commune-level. We will then use these products to conduct an attribution study (1990-2020) at the commune-level in metropolitan France.
Finally, we will determine how heat-related health impacts are associated with contextual socioeconomic status (FDep index) as well as historical CO2 emissions level.

| Perspectives

This project’s novelty lies in the comprehensive assessment of heat exposure on various morbidity outcomes using one of the world’s largest and comprehensive universal healthcare databases; the use of state-of-the art epidemiological models including spatio-temporal analyses; the use of latest climate simulations to project heat-related morbidity and quantify the proportion attributed to human-induced climate change; and the characterization of adverse health impacts on a fine scale across climatologically and sociologically diverse locations in France.

In conclusion, this project will provide key results to better understand the past and future impacts of heat, the role of human-induced climate change in such relationships, and health inequalities related to heat. Such results will be directly relevant to inform local and national heat prevention plans, and long-term adaptations strategies to pro-actively prevent heat public health impacts in France.