The team analyzed the data of 15,744 people who participated in the Atherosclerosis Risk in Communities (ARIC) study, funded by the NIH's National Heart, Lung, and Blood Institute (NHLBI).
‘A persons chances of developing dementia increases with midlife cardiovascular risk factors like diabetes, hypertension, prehypertension, and smoking.’
From 1987-1989, the participants between the ages of 45 to 64 years underwent a series of medical tests during their initial examinations. They were examined four more times for the next 25 years.
Cognitive tests of memory and thinking were carried out during all, except the first and third exams.
- During an average of 23 follow-up years, 1,516 participants were diagnosed with dementia.
- When the research team analyzed the influence of factors during the first exams, the chances of dementia increased with age followed by the presence of APOE4, a gene which is associated with Alzheimer's disease.
- White Americans with one copy of APOE4 gene had a greater chance of dementia than black Americans.
- Blacks had a higher chance of dementia than whites. The team also found that participants who did not graduate from high school were also at higher risk.
- The research also discovered a link between dementia and pre-hypertension (blood pressure levels are higher than normal but lower than hypertension).
- Race did not have an association between dementia and the cardiovascular risk factors.
- Diabetes, high blood pressure and prehypertension increased the risk of dementia for white and black participants.
- Smoking increased the risk of dementia for whites, however not in blacks.
Previously conducted studies have shown that diabetes or high blood pressure had a higher chance of developing dementia
Diabetes is also a strong predictor of dementia as the presence of the APOE4 gene.
"Our results contribute to a growing body of evidence linking midlife vascular health to dementia. These are modifiable risk factors. Our hope is that by addressing these types of factors early, people can reduce the chances that they will have dementia later in life," said Dr. Gottesman.
Further analysis strengthened the findings that the cardiovascular risk factors identified in the study were linked to dementia. The research team reanalyzed the data and found similar results among participants who had a stroke.
Cardiovascular risk factors such as diabetes
, prehypertension, and smoking increased the risk of dementia for participants who did not have a stroke and those who had a stroke.
In a separate study, the research team analyzed brain scans from a subgroup of ARIC participants who did not have dementia at the beginning of the study. The findings showed that the presence of one or more cardiovascular risk factors during midlife was associated with higher levels of beta amyloid ( a protein that accumulated in the brains of Alzheimer's patients). However, this relationship was not affected by the presence of the APOE4 gene and not seen for risk factors present in later life.
In participants older than 65 years of the age, the presence of cardiovascular risk factors
was not associated with greater levels of beta amyloid.
Jacqueline D. Wright, Dr.P.H., program director at NHLBI, said, "With many years of data from a large and diverse population, the ARIC study is a powerful source of information for medical research. This epidemiologic study aimed to improve our understanding of atherosclerosis and heart disease and, through the investigators' efforts; it has become a great resource for research on dementia and other diseases of aging. The investments in longitudinal cohort studies like ARIC will benefit all of us for many years to come."
The research team plan to investigate ways in which subclinical, or undiagnosed, vascular risk factors may influence the brain and why race is associated with dementia.
Dr Walter J. Koroshetz, Director of NIH's National Institute of Neurological Disorders and Stroke (NINDS), said that dementia is a greater health concern. This study supports the importance of controlling cardiovascular risk factors like high blood pressure and diabetes early in life to prevent the risk of dementia as we age. What's good for the heart is good for the brain.
The study funded by the National Institutes of Health (NIH) was published in JAMA Neurology.
Dementia is a decline in mental ability, which affects the daily routine. Dementia is an overall term that describes a wide range of symptoms. Dementia is caused by damage to the brain cells. It interferes with the ability of the brain cells to communicate with each other. This can impair the memory, communication and language, ability to focus and pay attention, and visual perception. Dementia is a progressive disease; the symptoms start slowly and gradually get worse.
Risk Factors of Dementia
- Aging - The chances of developing dementia rise significantly with age
- Gender - Women are more likely to develop dementia than men
- Ethnicity - South Asian, African and people from African-Caribbean origin develop dementia more often
- Genetics - More than 20 genes have been found increase a person's risk of developing dementia
- Other risk factors - Cardiovascular risk factors (diabetes, hypertension, hyperlipidemia, and obesity), depression, Parkinson's disease, multiple sclerosis, HIV and Down's syndrome.
- What Is Dementia? - (http://www.alz.org/what-is-dementia.asp)