Natural disaster-induced dementia and cognitive decline: A meta-analysis and systematic review

Recently, some studies have noted a negative cognitive impact on individuals in the aftermath of large-scale natural disasters; however, the causal relationship between disasters and cognitive/neurodegenerative effects remains widely unexplored. This review analyzes the impact of natural disasters on the development of cognitive decline (CD), all-cause dementia, and Alzheimer's disease (AD) in disaster-affected individuals. Studies reported from their inception to August 2023 were obtained via public online databases. All data presented in this review was derived from precalculated study results, data presented within/alongside articles, or statistics calculated using data obtained by contacting the articles' authors for ancillary information. Data from 28 studies, representing 4,606,561 individuals, 158,994 CD events, 179,694 dementia events, and 47,193 AD events was included for analysis. The pooled odds ratio (OR) and 95% confidence interval (CI) estimates showed that natural disasters significantly increased the risk of CD (OR: 1.25, CI: 1.20–1.30), all-cause dementia (OR: 1.07, CI: 1.05–1.08), and AD (OR: 1.07, CI: 1.05–1.10) in disaster victims as opposed to less- or non-impacted individuals. The greatest effects were noted following hurricanes, earthquakes with tsunamis, and heat waves. The findings from this meta-analysis indicate that natural disasters are significantly associated with the development of CD, all-cause dementia, and AD.