Huimin Chen, Huimin Chen, Ling Ji, Yilin Wang, Iven Klineberg, Hui Chen, Hui Chen
BACKGROUND: Recent research suggests a potential link between tooth loss and cognitive decline among the elderly population, but longitudinal evidence remains limited. AIM: This meta-analysis aims to investigate the longitudinal relationship between dentition status (tooth loss/edentulism) and cognitive outcomes (dementia/MCI) in aging populations. METHOD: A systematic search was conducted across PubMed, Scopus, and Web of Science up to February 2025. Twenty-one longitudinal studies (N = 35 744 989 participants) meeting inclusion criteria were analysed. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random- or fixed-effects models. Study quality was assessed via the Newcastle-Ottawa Scale. RESULTS: Longitudinal evidence supports a connection between tooth loss and cognitive decline. Specifically, tooth loss was associated with increased risks of dementia (OR = 1.26 [1.07, 1.49]) and MCI (OR = 1.40 [1.14, 1.71]). Edentulism showed higher risks (dementia: OR = 1.16 [1.09, 1.23]; MCI: OR = 1.90 [1.07, 3.35]). Subgroup analyses revealed greater risks in women and Western populations. Denture use mitigated dementia risk in individuals with tooth loss (OR = 1.03 [0.82, 1.28]). CONCLUSION: Tooth loss may accelerate cognitive decline, with more severe loss correlating to greater deterioration. Dentures could help mitigate this effect by restoring chewing function. Given that tooth loss is a modifiable risk factor for cognitive impairment, preventive dental care and timely prosthodontic treatment may play a protective role in maintaining brain health among older adults.