Blood vessels in the retina may be indicative of brain health years before the onset of dementia. The study found that younger people who score low on intelligence tests tend to be at a higher risk for poorer health and a shorter lifespan.
The researchers wanted to explore the link between intelligence and brain health, so they used retinal imaging to look into vascular conditions in the brain by observing the blood vessels of the retina. Retinal blood vessels are an easy way to gain insight into brain health, as they share similar size, structure, and function with blood vessels in the brain.
The researchers examined data from over 1,000 people from New Zealand. They found that having wider retinal venules was linked to lower intelligence scores at the age of 38, even after adjusting for other associated factors. Wider retinal venules showed evidence of general cognitive impairment, along with lower scores on various intelligence tests.
Psychological scientist Idan Shalev said, “Digital retinal imaging is a tool that is being used today mainly by eye doctors to study diseases of the eye. But our initial findings indicate that it may be a useful investigative tool for psychological scientists who want to study the link between intelligence and health across the lifespan.”
The researchers concluded, “Increasing knowledge about retinal vessels may enable scientists to develop better diagnosis and treatments to increase the levels of oxygen into the brain and by that, to prevent age-related worsening of cognitive abilities.”
Damage to the eye retina caused by mild vascular disease was found to be linked to cognitive problems. Study author Mary Haan said, “Problems with the tiny blood vessels in the eye may be a sign that there are also problems with the blood vessels in the brain that can lead to cognitive problems. This could be very useful if a simple eye screening could give us an early indication that people might be at risk of problems with their brain health and functioning.”
The study included 511 women over the age of 69 who took tests to evaluate their thinking and memory every year for up to 10 years. Eye health was tested every four years, and brain scans were taken eight years into the study.
Thirty-nine women had retinopathy, and those women, one average, had lower scores on cognitive tests, compared to women without retinopathy. Furthermore, the women with retinopathy also had small vascular damage within the brain.
The study was supported by the National Heart, Lung and Blood Institute, the U.S. Department of Health and Human Services, Wyeth Pharmaceuticals, and the National Institute on Aging.