Being affected by cardiometabolic disease such as diabetes, heart disease and stroke, has been linked to an increased risk of dementia and Alzheimer’s disease.
A new study by researchers from Karolinska Institutet has suggested that the same genes may be behind the risk of cardiometabolic disease and dementia.
The findings have been published in European Heart Journal.
Cardiometabolic disease is a growing health concern
Cardiometabolic disease such as type 2 diabetes, heart disease and stroke are a growing issue within healthcare. The ageing population and improved healthcare has meant that people with cardiometabolic diseases are living longer. People who suffer from cardiometabolic diseases are also likely to get two or more of these conditions in a lifetime in their lifetime, this is known as cardiometabolic multimorbidity. This affects an estimated 30% of older adults and leads to increased mortality.
“We know that type 2 diabetes, heart disease and stroke are well-established individual risk factors for dementia. As the population ages, more and more people are affected by several co-morbid cardiometabolic diseases, but few studies have dealt with the effect of this multimorbidity on dementia risk and whether genetic factors affect the relationship,” said Abigail Dove, PhD student at the Aging Research Center, Karolinska Institutet and first author of the study.
The researchers examined sets of twins over the age of 60 who were registered in the Swedish Twin Registry between March 1998 and December 2002. Over 17,000 individuals were categorised based on whether they had one or more cardiometabolic diseases and whether still had these conditions.
All the participants in the study were cognitively healthy at the beginning of the study. The participants’ health status was monitored for up to 18 years, enabling the researchers to establish who eventually developed dementia and who did not.
“We discovered that cardiometabolic multimorbidity is linked to a more than doubled risk of vascular dementia and a 50% increased risk of Alzheimer’s disease,” said Abigail Dove.
Results showed that for each cardiometabolic disease a patient had, the risk of all types of dementia increased by 42%. The corresponding figure for Alzheimer’s disease was 26% and 64% for vascular dementia.
The disease can be more dangerous in early life
The researchers also found that the risk of dementia tended to be higher if a person was diagnosed with cardiometabolic diseases in middle age compared to those who developed the disease later in life. The study suggests that one explanation for this could be that if the disease appears earlier in life, it can be more aggressive.
“These findings underscore the need for special monitoring of individuals with cardiometabolic diseases to reduce their risk of developing dementia at an older age,” said Dove.
The researchers also closely examined around 400 specific pairs of twins from the study population that were “mismatched”, meaning the two twins in a pair differed from each other in terms of the prevalence of cardiometabolic disease and the possible development of dementia.
Among the mismatched dizygotic twins who shared 50% of their genes, the twin with cardiometabolic disease was more likely to have dementia. However, among mismatched pairs of identical twins who are genetic copies of each other, the risk of dementia was found to be equal, regardless of whether they had cardiometabolic disease.
“The results suggest that the same genetic factors may contribute to both cardiometabolic diseases and dementia,” concluded Dove.
