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# Summer heat in Italy raises deaths from nervous system and mental illness
- URL: https://www.coios.me/heat-attributable-death-fractions-in-italy-are-highest-for/
- Published: 2026-10-10T08:10:15.000Z
- Updated: 2026-10-10T22:45:02.000Z
- Description: Across 7,864 Italian municipalities over 20 summers, heat-attributable fractions were highest for nervous system diseases at 14.93% and mental and behavioural disorders at 14.47%.
- Author: Daniel Ryan
- Tags: Tomorrow's world, A changing climate, Italy, #preprint, #refines, #item, #source-2026-10

Daily deaths in eight cause groups were linked to daily maximum temperature across 7,864 Italian municipalities, for June to August between 2004 and 2023\. Associations spanned a broad range of causes, particularly among those aged 65 and over, with the highest attributable fraction for nervous system diseases at 14.93%. Circulatory disease carried the largest absolute burden, at 85,524 heat-attributable deaths over the 20 summers.

*Why it is interesting: Heat attribution usually stops at cardiorespiratory causes; here neurological and mental causes carry the highest attributable shares.*

Source

[medRxiv, 6 October 2026](https://doi.org/10.64898/2026.10.02.26364563?ref=coios.me)

Paper

Cause-specific mortality attributable to summer heat in Italy, 2004–2023: a nationwide Bayesian spatiotemporal study

Authors

Ceccarelli E, Stoppa G, Blangiardo M, Konstantinoudis G, Vanacore N, Jona Lasinio G et al.

DOI

10.64898/2026.10.02.26364563

Type

Preprint

Design

Bayesian hierarchical spatiotemporal Poisson analysis of daily deaths by cause, 7,864 Italian municipalities, June-August 2004-2023

Verdict

Refines prior evidence

Driver

[A changing climate](https://www.coios.me/d-climate/)

Abstract — the authors' own words, CC BY

Background

Italy experiences a substantial heat-related mortality burden, but evidence on cause-specific mortality across its heterogeneous climatic settings remains limited. We aimed to quantify cause-specific mortality attributable to summer heat in Italy at national and ecological region levels and to map its distribution across municipalities. Methods

We analysed daily deaths classified by underlying cause in eight ICD-10 groups among individuals aged 18–64 years and 65 years or older across 7,864 municipalities during June–August, 2004–2023\. Mortality data were linked to area-weighted ERA5-Land daily maximum temperature. Nonlinear temperature–mortality associations were estimated with Bayesian hierarchical Poisson models, fitted separately for each cause, age group, and ecological region, with municipality-level attributable fractions. Findings

High temperatures were associated with mortality from a broad range of causes, particularly among individuals aged 65 years or older. Among the study population, heat-attributable fractions were highest for nervous system diseases (14 · 93%, 95% credible inter-val 14 · 22–15 · 69) and mental and behavioural disorders (14 · 47%, 13 · 55–15 · 39). Circulatory diseases accounted for the largest absolute burden, with 85,524 heat-attributable deaths (82,762–88,271) across the summers of the 20 years considered. Interpretation

The mortality burden associated with summer heat in Italy extended well beyond circulatory and respiratory diseases, highlighting the relevance of a broader range of health outcomes. These findings support heat–health strategies that account for cause-specific and geographical differences in heat-related risk, with greater consideration of neurological and mental health outcomes alongside established cardiorespiratory risks. Funding

NextGenerationEU (CUP: B53C23002660006); Imperial College Research Fellowship; NIHR Imperial Biomedical Research Center (BRC: NIHR203323). Research in context

Evidence before this study

We searched PubMed from database inception to 6 August 2026, combining exposure terms (“heat”, “high temperature”, or “ambient temperature”) with mortality terms (“mortality”, “cause-specific mortality”, or “cause of death”). Additional searches included terms related to attributable burden (“attributable fraction” or “attributable burden”) and geographical setting (“Italy” or “Europe”). We considered population-based observational studies examining mortality associated with high ambient temperatures, with particular attention to studies reporting cause-specific associations or attributable burden. Previous studies have consistently associated high ambient temperatures with increased mortality. Cause-specific analyses have shown that the effects of heat extend beyond cardiovascular and respiratory diseases to mental and behavioural, neurological, endocrine and metabolic, genitourinary, digestive, and external causes. However, much of the European evidence has been based on selected cities or relatively large administrative areas, and geographical variation has generally been characterised using administrative regions or broad climatic zones. Evidence on the fine-scale spatial distribution of cause-specific heat-attributable mortality across Italy remains limited, particularly when accounting for geographical differences in temperature–mortality associations. Added value of this study

To our knowledge, this is the first nationwide Italian study to estimate cause-specific heat–mortality associations separately across ecological regions and to map the corresponding heatattributable burden at the municipality level. Using daily mortality records from all Italian municipalities over the 20-year period 2004–2023, we estimated heat–mortality associations separately across ecological regions and age groups within a Bayesian modelling framework, propagating uncertainty from the estimated exposure–response associations to the attributable burden. We found consistent heat-related mortality risks across all major causes of death among older adults, with the strongest associations observed for mental and behavioural disorders and diseases of the nervous system. Implications of all the available evidence

The available evidence supports considering a broader range of causes than cardiovascular and respiratory diseases alone in heat-health surveillance and prevention. Evidence of increased mortality for selected causes among adults aged 18–64 years also supports extending prevention beyond older populations. Accounting for heterogeneity across ecoregions reflects climatic variability across the country, provides a more accurate assessment of at-risk populations, and offers a framework applicable to other countries and regions characterised by similar climatic variability. These findings can support public health authorities in prioritising prevention measures and allocating resources where they are most needed under a warming climate.