Millions of people with eye conditions including age-related macular degeneration, cataracts and diabetes-related eye disease have an increased risk of developing dementia, new research shows.
Vision impairment can be one of the first signs of the disease, which is predicted to affect more than 130 million people worldwide by 2050.
Previous research has suggested there could be a link between eye conditions that cause vision impairment, and cognitive impairment.
However, the incidence of these conditions increases with age, as do systemic conditions such as diabetes, high blood pressure, heart disease, depression and stroke, which are all accepted risk factors for dementia. That meant it was unclear whether eye conditions were linked with a higher incidence of dementia independently of systemic conditions.
Now researchers have found that age-related macular degeneration, cataracts and diabetes-related eye disease are independently associated with increased risk of dementia, according to a new study published in the British Journal of Ophthalmology.
The research examined data from 12,364 British adults aged 55 to 73, who were taking part in the UK Biobank study. They were assessed in 2006 and again in 2010 with their health information tracked until early 2021.
More than 2,300 cases of dementia were documented, according to the international team of experts led by academics from the Guangdong Eye Institute in China.
After assessing health data, researchers found those with age-related macular degeneration had a 26% increased risk of developing dementia. Those with cataracts had an 11% increased risk and people with diabetes-related eye disease had a 61% heightened risk. Glaucoma was not linked to a significant increase in risk.
Researchers also found that people with conditions including diabetes, heart disease, stroke and depression were also more likely to be diagnosed with dementia. Risk was highest among people with one of these conditions who also had some form of eye condition, they said.
“Age-related macular degeneration, cataract and diabetes-related eye disease but not glaucoma are associated with an increased risk of dementia,” the authors concluded.
“Individuals with both ophthalmic and systemic conditions are at higher risk of dementia compared with those with an ophthalmic or systemic condition only.”
The study comes as Alzheimer’s Research UK says public willingness to get involved with medical research is at an “all-time high”. The charity said 29% of adults were more likely to consider getting involved in medical research because of the pandemic, according to a poll of 1,000 adults across England, Scotland and Wales.
The survey found that 69% said they would be willing to get involved with dementia research, compared with 50% of a sample of people from a year ago.
“This is positive news for the thousands of studies waiting to get under way to help understand and tackle health conditions like dementia, cancer, and heart disease,” said Hilary Evans, the chief executive of Alzheimer’s Research UK.