Age-related macular degeneration, cataracts and diabetes-related eye disease – but not glaucoma – are independently associated with increased risk of dementia, found a study in the British Journal of Ophthalmology.
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, and previous research has suggested 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 like diabetes, high blood pressure, heart disease, depression and stroke, which are all accepted dementia risk factors. That meant it was unclear whether eye conditions were linked with a higher incidence of dementia independently of systemic conditions.
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 this year.
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.
Those with age-related macular degeneration had a 26% increased risk of developing dementia; those with cataracts 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.
“Those with both ophthalmic and systemic conditions are at higher risk of dementia compared with those with an ophthalmic or systemic condition only.”
Study details
Associations of ophthalmic and systemic conditions with incident dementia in the UK Biobank
Xianwen Shang, Zhuoting Zhu, Yu Huang, Xueli Zhang, Wei Wang,
Danli Shi, Yu Jiang, Xiaohong Yang, Mingguang He.
Published in the British Journal of Ophthalmology September 2021
Abstract
Aims
To examine independent and interactive associations of ophthalmic and systemic conditions with incident dementia.
Methods
Our analysis included 12 364 adults aged 55–73 years from the UK Biobank cohort. Participants were assessed between 2006 and 2010 at baseline and were followed up until the early of 2021. Incident dementia was ascertained using hospital inpatient, death records and self-reported data.
Results
Over 1 263 513 person-years of follow-up, 2304 cases of incident dementia were documented. The multivariable-adjusted HRs (95% CI) for dementia associated with age-related macular degeneration (AMD), cataract, diabetes-related eye disease (DRED) and glaucoma at baseline were 1.26 (1.05 to 1.52), 1.11 (1.00 to 1.24), 1.61 (1.30 to 2.00) and (1.07 (0.92 to 1.25), respectively. Diabetes, heart disease, stroke and depression at baseline were all associated with an increased risk of dementia. Of the combination of AMD and a systemic condition, AMD-diabetes was associated with the highest risk for incident dementia (HR (95% CI): 2.73 (1.79 to 4.17)). Individuals with cataract and a systemic condition were 1.19–2.29 times more likely to develop dementia compared with those without cataract and systemic conditions. The corresponding number for DRED and a systemic condition was 1.50–3.24. Diabetes, hypertension, heart disease, depression and stroke newly identified during follow-up mediated the association between cataract and incident dementia as well as the association between DRED and incident dementia.
Conclusions
AMD, cataract and DRED but not glaucoma are associated with an increased risk of dementia. Individuals with both ophthalmic and systemic conditions are at higher risk of dementia compared with those with an ophthalmic or systemic condition only.
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