The cause for Alzheimer's disease is still unknown and now, a new study has shed light on the possible triggers of early Alzheimer's disease, linking it to cerebrovascular disease.
Diseased blood vessels in the brain itself, which is commonly found in elderly people, may contribute more significantly to Alzheimer's disease dementia than was previously believed, according to the research from the Rush Alzheimer's Disease Center.
"Cerebral vessel pathology might be an under-recognized risk factor for Alzheimer's disease dementia," the researchers wrote.
The study analyzed medical and pathologic data on 1,143 older individuals who had donated their brains for research upon their deaths, including 478 (42 percent) with Alzheimer's disease dementia.
Analyses of the brains showed that 39 percent of study participants had moderate to severe atherosclerosis, plaques in the larger arteries at the base of the brain obstructing blood flow, and 35 percent had brain arteriolosclerosis, in which there is stiffening or hardening of the smaller artery walls.
The study also found that the worse the brain vessel diseases, the higher the chance of having dementia, which is usually attributed to Alzheimer's disease. The increase was 20 to 30 percent for each level of worsening severity.
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The research also showed that atherosclerosis and arteriolosclerosis are associated with lower levels of thinking abilities, including in memory and other thinking skills, and these associations were present in persons with and without dementia.
"Both large and small vessel diseases have effects on dementia and thinking abilities, independently of one another, and independently of the common causes of dementia such as Alzheimer's pathology and strokes," said lead author Zoe Arvanitakis.
The study is published in journal The Lancet Neurology.