Affiliations: [a]
Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Haidian District, Beijing, China
| [b] Institute for Global Health and Development, Peking University, Haidian District, Beijing, China
| [c] Global Center for Infectious Disease and Policy Research & Global Health and Infectious Diseases Group, Peking University, Beijing, China
Correspondence:
[*]
Correspondence to: Prof. Jue Liu, Department of Epidemiology and Biostatistics, School of Public Health, Peking University; Institute for Global Health and Development, Peking University Beijing 100191, China. Tel.: +86 10 8 2801528 316; Fax: +86 10 8 2805146; E-mail: jueliu@bjmu.edu.cn.
Abstract: Background:Dementia is a critical global public health problem. Previous cohort studies have found that influenza vaccination can decrease the risk of dementia. Objective:This meta-analysis aimed to systematically examine the relationship between influenza vaccination and dementia risk. Methods:We searched PubMed, Embase, Web of Science, ScienceDirect, medRxiv, and bioRxiv for studies investigating dementia risk based on influenza vaccination status, up to September 14, 2022. Relative risks (RRs) and 95% confidence intervals (95% CIs) were pooled in the meta-analysis. Subgroup analyses and sensitivity analyses were conducted as well. Results:Of the 4,087 articles initially reviewed, 6 cohort studies were included in the final meta-analysis, and all eligible studies were at low risk of bias. There were 2,087,195 participants without dementia at baseline (mean age: 61.8–75.5 years, 57.05% males), and 149,804 (7.18%) cases of dementia occurred during 4.00–13.00 years of follow-up. Pooled analysis of adjusted RRs found that influenza vaccination could reduce dementia risk by 31% (RR = 0.69, 95% CI: 0.57–0.83). Subgroup analyses showed that in the study with a mean age of 75–80 years or 75%–100% males, the association was generally weakened compared with studies with a mean age of 60–75 years or 25%–50% males. The results were stable in the sensitivity analyses, and no publication bias was observed. Conclusion:Influenza vaccination in older adults was markedly associated with a decreased risk of dementia. More mechanistic studies and epidemiological studies are needed to clarify the association between influenza vaccination and decreased dementia risk.
