Pneumonia and subsequent risk of dementia: evidence from the Japan Gerontological evaluation study

Khairan, Paramita, Shirai, Kokoro, Shobugawa, Yugo, Cadar, Dorina, Saito, Tami, Kondo, Katsunori, Sobue, Tomotaka and Iso, Hiroyasu (2022) Pneumonia and subsequent risk of dementia: evidence from the Japan Gerontological evaluation study. International Journal of Geriatric Psychiatry, 37 (11). pp. 1-11. ISSN 0885-6230

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Recently, several studies reported that pneumonia might increase the risk of cognitive decline and dementia due to increased frailty.

This study aims to examine the association between a history of pneumonia and subsequent dementia risk.

Participants were 9952 aged 65 years or older Japanese men and women from the Japan Gerontological Evaluation Study prospective cohort study, followed up from 2013 to 2019. Dementia was identified by public long-term care insurance registration. A history of pneumonia contracted 1 year before the baseline questionnaire in 2013. A cox regression model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia risk, adjusted for potential confounding variables. We conducted competing risk analyses using a cause-specific hazard model.

During the follow-up period of 6 years, 939 persons developed dementia. There was no association between having a prior history of pneumonia with dementia risk (HR 1.20, 95% CI:0.81–1.78). However, we observed an increased risk of dementia in persons with pre-frailty and frailty; the multivariable HR (95% CI) was 1.75 (1.48–2.07) and 2.42 (2.00–2.93) for pre-frailty and frailty, respectively. When pneumonia and frailty were combined, the risk of dementia was the highest for the persons with a history of pneumonia and frailty; the multivariable HR (95% CI) was 2.30 (1.47–3.62). The multivariable HR (95% CI) for those without pneumonia with frailty was 1.95 (1.66–2.28). Meanwhile, the multivariable HR (95% CI) for those with pneumonia without frailty was 1.64 (0.68–3.99).

Our findings imply that a prior history of pre-frailty and frailty with or without pneumonia, but not a history of pneumonia per se, was associated with an increased risk of dementia among population-based-cohort of older Japanese people.

Item Type: Article
Additional Information: This is the peer reviewed version of the following article: "Pneumonia and subsequent risk of dementia: evidence from the Japan Gerontological evaluation study", which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
Keywords: cohort study, dementia, frailty, older population, pneumonia, Male, Humans, Female, Frailty, Japan, Prospective Studies;Dementia;Pneumonia
Schools and Departments: Brighton and Sussex Medical School > Neuroscience
SWORD Depositor: Mx Elements Account
Depositing User: Mx Elements Account
Date Deposited: 05 Jan 2023 11:58
Last Modified: 05 Jan 2023 12:00

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