Objectives Anxiety is an increasingly recognised predictor of cognitive deterioration in older adults and in those with mild cognitive impairment. Often believed to be a prodromal feature of neurodegenerative disease, anxiety may also be an independent risk factor for dementia, operationally defined here as preceding dementia diagnosis by ≥10 years.
Design A systematic review of the literature on anxiety diagnosis and long-term risk for dementia was performed following published guidelines.
Setting and participants Medline, PsycINFO and Embase were searched for peer-reviewed journals until 8 March 2017. Publications reporting HR/OR for all-cause dementia based on clinical criteria from prospective cohort or case–control studies were selected. Included studies measured clinically significant anxiety in isolation or after controlling for symptoms of depression, and reported a mean interval between anxiety assessment and dementia diagnosis of at least 10 years. Methodological quality assessments were performed using the Newcastle-Ottawa Scale.
Outcome measure HR/OR for all-cause dementia.
Results Searches yielded 3510 articles, of which 4 (0.02%) were eligible. The studies had a combined sample size of 29 819, and all studies found a positive association between clinically significant anxiety and future dementia. Due to the heterogeneity between studies, a meta-analysis was not conducted.
Conclusions Clinically significant anxiety in midlife was associated with an increased risk of dementia over an interval of at least 10 years. These findings indicate that anxiety may be a risk factor for late-life dementia, excluding anxiety that is related to prodromal cognitive decline. With increasing focus on identifying modifiable risk factors for dementia, more high-quality prospective studies are required to clarify whether clinical anxiety is a risk factor for dementia, separate from a prodromal symptom.
- anxiety disorders
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Contributors AG contributed to design of the study, data screening and extraction, drafting of the manuscript and submission. MS contributed to literature search, data screening and extraction and manuscript preparation. JDH contributed to the study design, provided methodological expertise and editing of the manuscript. NLM contributed to the conception and study design, data interpretation and editing of the manuscript.
Funding This work was supported by a grant from the British Geriatrics Society. NLM was supported by University College London and Alzheimer’s Society (AS-SF-15b-002).
Competing interests None declared.
Patient consent Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.
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