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Psychiatric Disorders Mediate the Association between Floods and Dementia: A Prospective Cohort Study in the UK Biobank
Yao Yu Wu, Bo Wen, Danijela Gašević, Rongbin Xu, Zhengyu Yang, Pei Yu, Yanming Liu, Guowei Zhou et al.. Environment & Health, 2025-03-13
Topic: Risk, prevention and care in population studies
Flooding has become more frequent and severe worldwide, leading to an increased burden of psychiatric disorders (e.g., depression and anxiety). Psychiatric disorders are associated with an increased risk of subsequent dementia. However, the associations among floods, psychiatric disorders, and dementia are still unclear. Using a population cohort from the UK Biobank, we aimed to investigate the mediating role of psychiatric disorders on the associations between floods and dementia. In this study, cumulative exposure to floods over an eight-year period preceding the study baseline was assessed for each participant at residential addresses. Multivariable Cox proportional hazards regression was used to study the associations of flooding exposure with psychiatric disorders and dementia. Stratified analyses and mediation analyses were conducted to examine whether psychiatric disorders mediate the relationship between floods and dementia. During a median follow-up of 12.3 years (interquartile range: 11.6-13.0), 0.9% (2,028) of participants developed dementia and 9.5% (21,629) were diagnosed with psychiatric disorders. The flooding exposure was associated with an 8.0% increased risk of incident dementia (Hazard Ratio [HR]: 1.080, 95% CI: 1.023-1.141). The flood-dementia association was observed to be partially mediated by several subtypes of psychiatric disorders (overall proportion of mediation: 75.7%), with psychotic disorder accounting for 49.7% (indirect effect HR: 1.039, 95% confidence interval: 1.015-1.064) of flood-related dementia, followed by stress-related disorder (proportion of mediation: 18.1%), and depression (proportion of mediation: 3.9%). This study provides evidence of an increased risk of dementia associated with exposure to floods, with psychiatric disorders playing a crucial mediating role in the flood-related dementia pathway. These findings suggest that flooding exposure is a critical risk factor for dementia, and targeted interventions addressing postdisaster mental health may be crucial for dementia prevention in affected populations.
Key findings
- Psychiatric disorders are associated with an increased risk of subsequent dementia.
- The flooding exposure was associated with an 8.0% increased risk of incident dementia (Hazard Ratio [HR]: 1.080, 95% CI: 1.023-1.141).
- The flood-dementia association was observed to be partially mediated by several subtypes of psychiatric disorders (overall proportion of mediation: 75.7%), with psychotic disorder accounting for 49.7% (indirect effect HR: 1.039, 95% confidence interval: 1.015-1.064) of flood-related dementia, followed by stress-related disorder (proportion of mediation: 18.1%), and depression (proportion of mediation: 3.9%).
- This study provides evidence of an increased risk of dementia associated with exposure to floods, with psychiatric disorders playing a crucial mediating role in the flood-related dementia pathway.
- These findings suggest that flooding exposure is a critical risk factor for dementia, and targeted interventions addressing postdisaster mental health may be crucial for dementia prevention in affected populations.
Why it matters
In this UK Biobank cohort, flood exposure was linked to an 8.0% higher risk of dementia, and this link was partly mediated by psychiatric disorders, especially psychotic disorder. The findings describe an environmental association and mediation pattern, not a treatment or prevention approach.
Study details
- Effect size0.9%; 9.5%; 8.0%
- Evidence strengthModerate
How this study scored 40/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Environment & Health) |
| Journal's citation record | 0 / 4 | Environment & Health: journal h-index 27 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 1 / 7 | Cited 2 times (OpenAlex, 2026-10-10) |
| Citations per year | 0 / 5 | 0.7 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 2 / 6 | Cited 1.3× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 0 / 4 | Cited 2 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Yuming Guo: h-index 120 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | University of Edinburgh: institution h-index 1,378 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 4 institution(s) in 3 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 40567268) |
| Free to read | 2 / 2 | Free to read |
| Total | 40 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1021/envhealth.4c00241
- PubMed: 40567268
- Original source →
- Free full text: Environment & Health →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Wu, Y. Y., Wen, B., Gašević, D., Xu, R., Yang, Z., Yu, P., et al. (2025). Psychiatric Disorders Mediate the Association between Floods and Dementia: A Prospective Cohort Study in the UK Biobank. Environment & Health. https://doi.org/10.1021/envhealth.4c00241
Vancouver
Wu YY, Wen B, Gašević D, Xu R, Yang Z, Yu P, et al. Psychiatric Disorders Mediate the Association between Floods and Dementia: A Prospective Cohort Study in the UK Biobank. Environment & Health. 2025. doi:10.1021/envhealth.4c00241. PMID: 40567268.
BibTeX
@article{wu2025-40567268,
author = {Wu, Yao Yu and Wen, Bo and Gašević, Danijela and Xu, Rongbin and Yang, Zhengyu and Yu, Pei and Liu, Yanming and Zhou, Guowei and others},
title = {{Psychiatric Disorders Mediate the Association between Floods and Dementia: A Prospective Cohort Study in the UK Biobank}},
journal = {Environment \& Health},
year = {2025},
doi = {10.1021/envhealth.4c00241},
pmid = {40567268},
url = {https://doi.org/10.1021/envhealth.4c00241}
}
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