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Distressing Dreams, Cognitive Decline and Risk of Dementia: A Prospective Study of Three Population-Based Cohorts
28 Pages Posted: 24 Jun 2022
More...Abstract
Background: Previous studies have shown that distressing dreams are associated with faster cognitive decline and increased dementia risk in people with Parkinson’s disease (PD). Whether distressing dreams might be associated with cognitive decline and dementia in people without PD is unknown. This study investigated the association between self-reported distressing dream frequency and the risk of cognitive decline and incident dementia in community-dwelling men and women without cognitive impairment or PD.
Methods: Annualised rates of decline in global cognitive function over a 9·3-year follow-up period were evaluated in 605 middle-aged men and women (35-64 years of age) from the Midlife in the United States (MIDUS) study. Rates of decline were calculated based on changes in cognitive test z scores between the baseline and follow-up visits. Risk of incident all-cause dementia was evaluated in 2269 older men and women (age 79+) from the Osteoporotic Fractures in Men Study (MrOS) and the Study of Osteoporotic Fractures (SOF), who were dementia-free at baseline, and were followed-up for 4·6 years on average. Incident dementia was based on doctor-diagnosis. Frequency of distressing dreams was assessed in all cohorts at baseline (January 2002 – September 2009) using item 5h of the Pittsburgh Sleep Quality Index. The association between self-reported distressing dream frequency (“never”, “less than weekly”, “weekly”) and later cognitive outcomes, was evaluated using multivariable linear regression in the middle-aged cohort, and multivariable logistic regression in the older adult cohort.
Findings: After adjustment for all covariates, a higher frequency of distressing dreams was linearly and statistically significantly associated with faster rates of cognitive decline among middle-aged adults (P for trend = 0·014), and increased risk of incident all-cause dementia among older adults (P for trend = 0·005). The difference in decline rates for participants with weekly distressing dreams versus those who never experienced them, was equivalent to being 17 years older. The difference in dementia risk was 2-fold.
Interpretation: Distressing dreams are associated with faster cognitive decline and increased dementia risk in middle-aged and older adults without cognitive impairment or PD. These findings may help to identify individuals at risk of dementia and could facilitate early prevention strategies.
Funding: The study received no external funding.
Declaration of Interest: The author declares no conflict of interest.
Ethical Approval: All participants provided written informed consent. The original studies were approved by the institutional review boards involved with MIDUS, SOF and MrOS. The present study received approval from the University of Birmingham (Ref No ERN_21-1463).
Keywords: Dreaming, Cognitive decline, Dementia, Nightmares
Suggested Citation: Suggested Citation