The CARDIA study explored the link to the decline in cognitive abilities in diseases like Alzheimer’s and Parkinson’s in middle-aged populations.
An analysis of adults aged 50 and over without dementia at baseline found that hypertension increased the risk of cognitive decline by 87%. The risk of a person having acute cognitive impairment triples due to having chronic diseases such as hypertension and diabetes. The mental impairment level differed based on the duration the patient had a chronic illness and cardiovascular risk factors such as high blood pressure and diabetes, which are more common in people in their 40s. Previous studies have established associations between midlife cardiovascular risk factors and the risk of dementia, although some have examined whether these risk factors affect midlife cognition. A team of colleagues hoped to investigate the possible associations between risk factors, including hypertension, dyslipidemia, diabetes, and obesity, on the risk of coronary artery disease in young adults (CARDIA).
To serve the benefit of this analysis, the researchers included only those participants who completed the cognitive tests at 25 years of the study, which was considered as the reference for the current research, and five years later. Overall, the researchers identified 2,675 middle-aged adults to be included in their study. The mean age of the patients enrolled in the study was 50.2 years ± 3.6 years, 57% of the participants were women, and 45% were black.
In the study population, 31% were considered hypertensive, 11% were deemed diabetic, 43% obese, 9% high cholesterol, and 15% were current cigarette smokers at baseline. For objective analysis, patients were classified according to the number of risk factors present, defined as 0, 1, 2, and 3 or more.
An accelerated decline occurred in 143 participants during the observation period averaging 5.02 ± 0.34 years. After analysis, researchers found that diabetes (RR, 2.45; 95% CI, 1.54-3.88), hypertension (RR, 1.87; 95% CI, 1.26-2.75), and smoking (RR 1.65; 95% CI 1.00-2.71) were linked with an increased risk of accelerating the decline in the multivariate-adjusted analysis. Conversely, obesity and high cholesterol do not appear to be associated with an increased risk of accelerated decline.
Surprisingly, people who were considered obese and high in cholesterol did not have an increased risk of cognitive impairment, as stated by the researchers. Other studies have shown a link between obesity and dementia, but mostly in older people. Meanwhile, studies looking at high cholesterol and dementia have found mixed results, so this study complements these studies.
When examining the likelihood of an accelerated decline based on the number of existing risk factors, the researchers found 1-2 risk factors (RR, 1.77; 95% CI, 1.02-3.05) and three or more risk factors (RR, 2, 94; 95% CI, 1.64-5.28) were more likely than those with 0 risk factors. The analysis also showed that a Framingham score for cardiovascular risk of 10 or more was also associated with an increased probability of having a cognitive impairment (95% CI, 1.21-4.34).
The researchers noted several limitations to consider, including the inability to assess each cognitive domain, the Framingham coronary heart disease risk score being developed in a more homogeneous cohort, and that the characterization of mental changes in middle-aged adults is not well defined.
The link between cardiovascular risk factors, diabetes, and hypertension and their connection to dementia is well known. Attention has been drawn to modifiable risk factors to stop the increasing prevalence of dementia, and multiple studies have shown mixed and unreliable results. However, the increased improvement in diabetes control lowered the cognitive impact on patients with diabetes. On the other hand, most of the data are collected from elderly patients. There is minimal evidence about the onset and start time of cognitive impairment and the prevalence of cognitive dysfunction among middle-aged adults with diabetes.
Because it was shown that increasing prevalence of dementia is linked to diabetes, so the improvement of cognitive function would be very expected with better diabetes control. It is essential to understand if younger patients with diabetes are suffering from the same consequences of dementia and cognitive impairment in the future, and thus could benefit from preventive strategies.
- Controlling hypertension and diabetes is imperative to the prevention of cardiac dysfunction.
- Younger patients could also be at risk of cognitive impairment as a result of untreated diabetes.
- The CARDIA study explored the factors linked to the decline in cognitive abilities in diseases like Alzheimer’s and Parkinson’s in middle-aged populations.
Kristine Yaffe et. al., “Cardiovascular risk factors and accelerated cognitive decline in midlife: The CARDIA Study.” Neurology, Aug. 18, 2020.
Olivia Shenouda, Fourth–year Doctor of Pharmacy Candidate, Florida A&M University