The study finds that dementia risk is increased by diabetes and cardiovascular disease.
People who have at least two of the conditions type 2 diabetes, heart disease, or stroke are twice as likely to develop dementia. Research from Sweden’s Karolinska Institutet that was published in the journal Alzheimer’s & Dementia suggests the possibility that preventing diabetes and cardiovascular disease might be a tactic for lowering dementia risk.
Some of the major risk factors for dementia are type 2 diabetes, heart diseases (ischemic heart disease, heart failure, or atrial fibrillation), and stroke, together referred to as cardiometabolic diseases.
“Few studies have examined how the risk of dementia is affected by having more than one of these diseases simultaneously, so that’s what we wanted to examine in our study,” says Abigail Dove, a doctoral student at the Aging Research Centre, part of the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet.
Over many years, dementia progressively develops. It initially appears as a slow deterioration in cognitive function that is only detected in cognitive testing. After that, it progresses to cognitive impairment, in which the person can still care for themselves but observes that their memory is deteriorating, and lastly to full-blown dementia.
Having more than one cardiometabolic disease doubles the risk
Data on 2,500 healthy, dementia-free people over 60 living on Kungsholmen in Stockholm were taken from the Swedish National Study on Aging and Care. Medical records and clinical examination were used to determine the prevalence of cardiometabolic diseases at the beginning of the trial. The patients were then evaluated medically and given cognitive tests over the course of twelve years to track changes in cognitive function and the development of dementia.
Multiple cardiometabolic diseases doubled the likelihood of cognitive impairment and dementia and hastened their onset by two years. They also sped up the pace of cognitive decline. More diseases were associated with a larger degree of risk.
“In our study, the combinations of diabetes/heart disease and diabetes/heart disease/stroke were the most damaging to cognitive function,” says Dove.
Prevention of a second disease important
However, individuals who had just one cardiometabolic disease did not display a significantly higher risk of dementia.
“This is good news. The study shows that the risk only increases once someone has at least two of the diseases, so it’s possible that dementia can be averted by preventing the development of a second disease.”
The correlation between cardiometabolic diseases and the risk for dementia was stronger in the participants who were under 78 years old.
“We should therefore focus on cardiometabolic disease prevention already in middle age, since the risk of cognitive failure and dementia appears higher among those who develop a cardiometabolic disease earlier in life,” says Dove.
Seeking to understand the mechanism
The researchers hope in future studies to learn more about the mechanism driving this correlation by examining the impact of genetic factors and using brain imaging to see how cardiometabolic diseases might damage the brain.
Reference: “Cardiometabolic multimorbidity accelerates cognitive decline and dementia progression” by Abigail Dove, Anna Marseglia, Ying Shang, Giulia Grande, Davide Liborio Vetrano, Erika J Laukka, Laura Fratiglioni and Weili Xu, 16 June 2022, Alzheimer’s & Dementia.
The study was funded by 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 have been reported.