Risk of dementia in older patients with different anesthesia: a systematic review and meta-analysis of cohort studies.

backgroundAnesthesia has been hypothesized to influence dementia risk due to its potential neurotoxic effects, especially in older patients. The administration of anesthetic agents may exacerbate underlying neurodegenerative processes. This study aimed to assess the risk of dementia, Alzheimer’s disease (AD), and Alzheimer’s disease and related dementia (ADRD) in older patients who underwent general or regional anesthesia.

methodsWe conducted a systematic review and meta-analysis to explore the associations between different types of anesthesia and the risk of dementia, AD, and ADRD in older patients. We searched Cochrane Library, PubMed, Web of Science, and EMBASE databases from inception to 13, February 2025. Two authors independently selected eligible studies, used the Newcastle-Ottawa Scale to assess the quality of included studies, and extracted data. Any disagreements were resolved through discussions involving a third author.

resultsEight population-based cohort studies were included and considered as high quality. Our findings indicated that the type of anesthesia (general or regional) did not increase the risk of dementia (hazard ratio [HR] 1.30, 95% confidence interval [CI] 0.85–2.00), AD (HR 0.83, 95% CI 0.55–1.25),ADRD (HR 0.95, 95% CI 0.84–1.08), or composite outcome dementia (HR 1.17, 95% CI 0.90–1.52). We also found no increase in the risk of dementia (HR 1.33, 95% CI 0.30–5.94), AD (HR 0.83, 95% CI 0.55–1.25, or composite outcome dementia (HR 1.06, 95% CI 0.72–1.56) among older patients underwent general anesthesia. In the stratified analysis, we found differences between male and female in terms of increased risk of dementia, AD or ADRD (HR 0.89, 95% CI 0.82–0.96).We also found no increase in dementia, AD or ADRD among older patients exposed to different anesthesia protocols between Asia and North America.

conclusionsThe available limited, low-quality evidence does not indicate an increased risk of dementia in older patients exposed to general or regional anesthesia. However, it is necessary to acknowledge that anesthesia may influence cognitive function.