Cardiovascular risk factors, such as diabetes and high blood pressure, increase the risk of dementia. That is not new information, but a long-term funded study by the National Institutes of Health found that not only is diabetes almost as strong a predictor of dementia as the APOE4 gene, but also prehypertension.
The researchers analyzed data on 15,744 participants aged 45 to 64 years in the Atherosclerosis Risk in Communities (ARIC) study. Over 25 years, the participants were examined 4 times, including being given cognitive tests during all but the first and third exams.
Over an average of 23 follow-up years, 1,516 people were diagnosed with dementia. During the time of the first exams, the risk of dementia increased most strongly with age, followed by the presence of APOE4. But as time went on, the link between cardiovascular risk factors and dementia became clearer. A separate study of an ARIC subgroup found that the presence of ≥ 1 vascular risk factor during midlife was associated with higher levels of beta amyloid, a protein that often accumulates in the brains of Alzheimer patients. The relationship was not affected by the presence of the APOE4 gene.
When the researchers reanalyzed the data according to who had a stroke, they found similar results: Diabetes, hypertension, prehypertension, and smoking raised the risk of dementia for people who had a stroke and those who had not.
“Our results contribute to a growing body of evidence linking midlife vascular health to dementia,” said study leader Rebecca Gottesman, MD, PhD, professor of neurology at Johns Hopkins University in Maryland. “These are modifiable risk factors. Our hope is that by addressing these types of factors early, people can reduce the chances that they will suffer from dementia later in life.”