Middle-aged persons who have cardiovascular health risk factors, such as diabetes, high blood pressure and are also current smokers, have a greater chance of suffering from dementia later in life, researchers have warned.
The findings showed that the chances of dementia increased most strongly with age followed by the presence of APOE4 — a gene associated with Alzheimer's disease.
Diabetes or high blood pressure, also called hypertension, increased the chances of developing dementia.
Importantly, diabetes was found to be almost as strong a predictor of dementia as the presence of the APOE4 gene, the researchers said.
"Our results contribute to a growing body of evidence linking midlife vascular health to dementia," said Rebecca Gottesman, Professor at the Johns Hopkins University in Baltimore, US.
However, "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," Gottesman added.
In addition, the researchers also discovered a link between dementia and prehypertension — a condition in which blood pressure levels are higher than normal but lower than hypertension.
Diabetes, hypertension and prehypertension increased the chances of dementia for participants, irrespective of race. Finally, smoking cigarettes also increased the chances of dementia, the researchers noted.
For the study, published in JAMA Neurology, the team analysed the data of 15,744 persons, from 1987-1989 aged 45-64 years.
During an average of 23 follow-up years, the researchers found 1,516 participants were diagnosed with dementia.
In a separate study, Gottesman found that the presence of one or more vascular risk factors during midlife was associated with higher levels of beta amyloid — a protein that often accumulates in the brains of Alzheimer's patients.
This relationship was not affected by the presence of the APOE4 gene and not seen for risk factors present in later life, the researchers said.