Swedish research team "Overall cognition, episodic memory, and perception speed are low in those in their 60s, stroke risk increases."
(Seoul = Yonhap News) Reporter Lee Joo-young = People in their 60s with low overall cognitive function had an 86% higher risk of stroke later than those without low cognitive function, and those with low memory and perception speed had a 68% and 66% higher risk, respectively.
Dr. Alice Askemir's team at Lund University and Skåne University Hospital in Sweden announced on the 1st in the Journal of the American Heart Association that they followed 4,900 adults over 60 years of age for more than 12 years and confirmed this relationship between cognitive function and the occurrence of the first stroke.
Dr. Askemir said, “The fact that cognitive decline appears at a relatively young age suggests the possibility of undetected brain damage,” and added that it remains to be determined whether cognitive decline itself increases the risk of stroke, or whether changes in the brain blood vessels that have already progressed also have an effect.
The research team explained that the relationship between cognitive decline in various cognitive domains and the occurrence of stroke has not been sufficiently studied, and that this study investigated the association between functional decline in multiple cognitive domains in older adults and the risk of first stroke.
They administered standardized tests measuring memory, perceptual speed, verbal fluency, and executive function to 4,912 people in their 60s or older who participated in the Good Aging in Skåne region, and followed them for an average of 12.3 years to see if they had their first stroke.
The participants did not have dementia or stroke at the start of the study, and 3,094 people were in their 60s, 494 in their 70s, and 1,184 people in their 80s or older.
Based on the test results, cognitive function was divided into low, medium, and high and the stroke risk of the highest and lowest groups was compared. There were 572 people diagnosed with their first stroke during the follow-up period.
The results of the analysis showed that in the 60-69 age group, the risk of stroke in the group with low overall cognitive function was 86% higher than in the group with high cognitive function.
The group with low episodic memory had a 68% higher risk of stroke than the group with high episodic memory, and the group with slow perception speed also had a 66% higher risk of stroke than the group with fast perception speed.
However, in the 70-79 age group and the 80+ age group, when adjusting for other health and lifestyle factors, no significant difference in stroke risk was identified between the high and low cognitive function groups.
The research team said that this shows that the relationship between cognitive function and stroke may appear differently depending on age, and suggested the possibility that the differences between those in their 60s and those older than that may be related to various medical factors and differences in follow-up periods.
In particular, older participants tended to have shorter follow-up periods as they died from other causes, and this dropout bias may have influenced the differences by age group.
When only men in their 60s were analyzed separately, the risk of stroke in the group with low overall cognitive function, episodic memory, and perceptual speed was 2.11, 2.30, and 1.77 times higher, respectively. However, in women, no statistically significant association was confirmed in the same analysis.
The research team explained that existing cerebrovascular damage, such as asymptomatic cerebral infarction, white matter changes, and cerebral microhemorrhage, may be related to both cognitive decline and stroke risk, and that cognitive decline may reflect pre-existing cerebrovascular damage.
However, since this study was an observational study, it shows a correlation between the two phenomena, but does not prove a causal relationship, and said that it should not be interpreted that a stroke occurs just because a cognitive test score is low.
He went on to say that the core of this study is that it suggests the possibility that the results of a cognitive test for people in their 60s could be a clue to future stroke risk, and that future research is needed to use cognitive tests together with other biomarkers and to investigate the relationship between cognitive decline, existing cerebrovascular damage, and subsequent stroke using magnetic resonance imaging (MRI).
◆ Source: Journal of the American Heart Association, Alice Askemyr et al., 'Lower Cognitive Function in People Aged 60 to 69 Years Is Associated With Future Stroke', http://dx.doi.org/10.1161/JAHA.125.048423
