Bipolar disorder and risk of all-cause and specific dementia: a systematic review and meta-analysis.
- 1School of Public Health, Shanxi Medical University, Taiyuan, China.
Abstract
Background
Bipolar disorder (BD) is associated with cognitive impairment and an increased risk of dementia; however, the magnitude of this association and subtype-specific risk patterns remain unclear. This systematic review and meta-analysis quantified the associations between BD and the risks of all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD), and explored potential sources of between-study heterogeneity.Methods
PubMed, Embase, the Cochrane Library, and Web of Science were searched from inception to September 15, 2026. Eligible cohort and case-control studies reported adjusted effect estimates for the association between BD and dementia. Hazard ratios and odds ratios were converted to risk ratios (RRs) prior to quantitative synthesis. Random- or fixed-effects models were applied according to heterogeneity. Leave-one-out sensitivity analyses, Egger's test for publication bias, and subgroup analyses stratified by follow-up duration, sex, age at BD onset, and study design were conducted.Results
Eleven studies involving 1,536,508 participants and 90,864 all-cause dementia cases were included. BD was associated with an increased risk of all-cause dementia (RR = 3.55, 95% CI 2.48-5.07; I² = 98.7%), AD (RR = 5.08, 95% CI 1.87-13.84; I² = 97.2%), and VaD (RR = 4.33, 95% CI 3.06-6.13; I² = 71.7%). Estimates for all-cause dementia and VaD were robust in sensitivity analyses, whereas the AD estimate was sensitive to the exclusion of individual studies and should therefore be interpreted cautiously. The association between BD and increased dementia risk was observed across the examined subgroups. Formal tests for subgroup differences showed no statistically significant differences according to sex or age at BD onset.Conclusion
BD is associated with an increased risk of all-cause dementia, AD, and VaD. However, substantial between-study heterogeneity and the limited evidence available for specific dementia subtypes warrant cautious interpretation of the pooled estimates. Further high-quality longitudinal studies are needed to clarify the factors underlying heterogeneity and subtype-specific associations.Systematic review registration
https://www.crd.york.ac.uk/prospero/, identifier [CRD420261395626].
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BibTeX
@article{gao2026bipolar,
title = {{Bipolar disorder and risk of all-cause and specific dementia: a systematic review and meta-analysis.}},
author = {Zihan Gao and Meiling Ren and Ruiji Yang and Jiahui Yu},
journal = {Frontiers in aging neuroscience},
year = {2026},
month = oct,
doi = {10.3389/fnagi.2026.1980508},
url = {https://europepmc.org/article/MED/42948010},
note = {CC BY},
}
RIS
TY - JOUR
TI - Bipolar disorder and risk of all-cause and specific dementia: a systematic review and meta-analysis.
AU - Zihan Gao
AU - Meiling Ren
AU - Ruiji Yang
AU - Jiahui Yu
PY - 2026
DA - 2026/10/13
JO - Frontiers in aging neuroscience
DO - 10.3389/fnagi.2026.1980508
UR - https://europepmc.org/article/MED/42948010
AB - Background Bipolar disorder (BD) is associated with cognitive impairment and an increased risk of dementia; however, the magnitude of this association and subtype-specific risk patterns remain unclear. This systematic review and meta-analysis quantified the associations between BD and the risks of all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD), and explored potential sources of between-study heterogeneity.Methods PubMed, Embase, the Cochrane Library, and Web of Science were searched from inception to September 15, 2026. Eligible cohort and case-control studies reported adjusted effect estimates for the association between BD and dementia. Hazard ratios and odds ratios were converted to risk ratios (RRs) prior to quantitative synthesis. Random- or fixed-effects models were applied according to heterogeneity. Leave-one-out sensitivity analyses, Egger's test for publication bias, and subgroup analyses stratified by follow-up duration, sex, age at BD onset, and study design were conducted.Results Eleven studies involving 1,536,508 participants and 90,864 all-cause dementia cases were included. BD was associated with an increased risk of all-cause dementia (RR = 3.55, 95% CI 2.48-5.07; I² = 98.7%), AD (RR = 5.08, 95% CI 1.87-13.84; I² = 97.2%), and VaD (RR = 4.33, 95% CI 3.06-6.13; I² = 71.7%). Estimates for all-cause dementia and VaD were robust in sensitivity analyses, whereas the AD estimate was sensitive to the exclusion of individual studies and should therefore be interpreted cautiously. The association between BD and increased dementia risk was observed across the examined subgroups. Formal tests for subgroup differences showed no statistically significant differences according to sex or age at BD onset.Conclusion BD is associated with an increased risk of all-cause dementia, AD, and VaD. However, substantial between-study heterogeneity and the limited evidence available for specific dementia subtypes warrant cautious interpretation of the pooled estimates. Further high-quality longitudinal studies are needed to clarify the factors underlying heterogeneity and subtype-specific associations.Systematic review registration https://www.crd.york.ac.uk/prospero/, identifier [CRD420261395626].
SN - 1663-4365
ER -