Summary: Having two or more cardiometabolic conditions—type 2 diabetes, heart disease or stroke—substantially raises the risk of developing dementia, according to researchers.
Source: Karolinska Institute
New research from Karolinska Institutet indicates that people who have at least two cardiometabolic conditions—type 2 diabetes, ischemic heart disease, heart failure or atrial fibrillation, and stroke—face roughly double the risk of cognitive decline and dementia compared with those without these conditions. The findings, published in the journal Alzheimer’s & Dementia, suggest that preventing the onset of a second cardiometabolic disease may be an effective strategy to reduce dementia risk.
Cardiometabolic diseases (CMDs) are well-established contributors to cognitive decline. This study set out to determine how having multiple CMDs influences the trajectory from normal cognition to cognitive impairment and ultimately to dementia.
“Relatively few studies have examined the combined impact of these diseases on cognitive outcomes,” says Abigail Dove, doctoral student at the Aging Research Centre within the Department of Neurobiology, Care Sciences and Society at Karolinska Institutet. “We wanted to understand whether having more than one condition accelerates decline and increases the likelihood of dementia.”
Dementia typically evolves over many years, beginning with subtle declines detectable only on cognitive tests, progressing to noticeable cognitive impairment in daily life, and ultimately leading to full dementia. Identifying modifiable risk factors that influence this progression is critical to prevention efforts.
Study design and key findings
The research analyzed data from the Swedish National Study on Aging and Care, including 2,500 dementia-free residents aged 60 and older living in the Kungsholmen district of Stockholm. Baseline assessments used medical records and clinical examinations to identify the presence of type 2 diabetes, heart disease and stroke. Participants underwent regular medical and cognitive testing over a 12-year follow-up period to monitor cognitive trajectories and the onset of cognitive impairment and dementia.
The presence of two or more cardiometabolic diseases was associated with faster cognitive decline, a higher risk of developing cognitive impairment no dementia (CIND), and a greater likelihood that CIND would progress to dementia. Compared with participants without CMD multimorbidity, those with multiple conditions experienced an accelerated onset of CIND by about 2.3 years and of dementia by about 1.8 years. The risk increased in a dose-dependent manner with the number of cardiometabolic conditions present.
“Combinations that included diabetes—particularly diabetes with heart disease, and the trio of diabetes, heart disease and stroke—were among the most harmful to cognitive health,” Dove reports.
Prevention matters: avoiding a second condition
Importantly, the study found that having a single cardiometabolic disease did not significantly raise dementia risk. This suggests a potential window for intervention: preventing the development of a second CMD may substantially reduce the likelihood of cognitive decline and dementia in individuals who already have one condition.
The association between CMD multimorbidity and dementia risk was strongest in participants younger than 78, highlighting the importance of addressing cardiometabolic health earlier in life. “These findings reinforce the need for prevention efforts starting in middle age, since earlier onset of cardiometabolic disease appears linked to higher risk of cognitive decline later on,” says Dove.
Next steps: understanding mechanisms
The research team plans further studies to clarify the biological mechanisms underlying the observed associations. Future work will examine genetic contributors and incorporate brain imaging to better understand how cardiometabolic conditions may damage brain structure and function and accelerate cognitive decline.
Funding: The study received support from the Swedish Research Council, the Swedish Research Council for Health, Working Life and Welfare (Forte), the Swedish Alzheimer’s Foundation and Lindhés Advokatbyrå. No commercial interests were reported.
About this dementia research news
Author: Press Office
Source: Karolinska Institute
Contact: Press Office – Karolinska Institute
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Original Research: Closed access. “Cardiometabolic multimorbidity accelerates cognitive decline and dementia progression” by Abigail Dove et al., Alzheimer’s & Dementia.
Abstract
Cardiometabolic multimorbidity accelerates cognitive decline and dementia progression
Introduction
Individual cardiometabolic diseases have been linked to poor cognitive outcomes, but the combined effect of multiple cardiometabolic conditions has been less well studied. This research addresses how multimorbidity among cardiometabolic conditions influences cognitive trajectories and dementia risk.
Methods
A cohort of 2,577 dementia-free participants aged 60 or older was followed for 12 years to observe changes in cognitive function and the emergence of cognitive impairment and dementia. Baseline assessments of cardiometabolic disease—type 2 diabetes, heart disease, and stroke—were based on medical records and clinical examinations. Cardiometabolic multimorbidity was defined as having two or more of these conditions. Analyses used multivariable linear mixed-effects models, Cox regression and Laplace regression to estimate effects on cognitive decline and time to clinical outcomes.
Results
Cardiometabolic multimorbidity was associated with greater cognitive decline, higher incidence of cognitive impairment no dementia (CIND) (hazard ratio 1.73; 95% confidence interval 1.23–2.44), and increased progression from CIND to dementia (hazard ratio 1.86; 95% confidence interval 1.17–2.97). Multimorbidity accelerated the onset of CIND by approximately 2.3 years and dementia by roughly 1.8 years.
Conclusions
Having multiple cardiometabolic diseases accelerates cognitive decline and raises the risk of both cognitive impairment and conversion to dementia. Preventing the development of additional cardiometabolic conditions among those already affected could be a key target for preserving cognitive health.
Highlights
- Examined the combined effect of cardiometabolic diseases on cognition.
- An increasing number of cardiometabolic diseases was associated with faster cognitive decline in a dose-dependent manner.
- Cardiometabolic multimorbidity raised the risk of cognitive impairment and dementia.
- Preventing co-existing cardiometabolic conditions may offer an opportunity to protect cognitive health.