Common eye conditions such as cataract, diabetic-related eye disease (DRED) and age-related macular degeneration (ARMD) are associated with an increased risk for dementia, according to a new study published in the British Journal of Ophthalmology.^1,2

The prospective study included a subgroup of 12,364 adults aged 55-73 years from the UK Biobank cohort. The participants self-reported their eye condition and/or systemic conditions.

The objective of the study was to examine associations of ophthalmic and systemic conditions with incident dementia. All the study participants were assessed between 2006 and 2010 at baseline and were followed until early 2021. During the 1,263,513 person-years of follow-up (median length of follow-up of 11 years), 2304 cases of all-cause dementia were recorded. There were 945 new cases of Alzheimer’s disease and 513 new cases of vascular dementia.

Results showed an independent association of ARMD, cataract and DRED with development of dementia, with highest association observed for ARMD. The hazard ratio for development of dementia with ARMD was 1.26; for cataract, the HR was 1.11 and for diabetes-related eye disease 1.61 compared with those who did not have an eye condition at baseline. However, no such association was seen for glaucoma (HR 1.07). Compared to those who had a single eye condition, the risk for dementia was higher in those  who had two eye conditions.

An association was also observed for systemic conditions such as diabetes, heart disease, stroke, depression.

Of particular interest was the observation that patients who had an eye condition as well as a systemic condition were at a higher risk of dementia vis-à-vis those who had either an eye condition or systemic condition alone. Those who had two eye conditions and two medical conditions at least tripled their risk of developing dementia.

The association between cataract or DRED and dementia was mediated by newly developed hypertension, diabetes, stroke, heart disease and depression, which are recognised risk factors of dementia. Also, risk factors such as older age, low levels of education, smoking and physical inactivity are common between eye conditions and dementia.

These findings suggest that middle-aged and older adults who have disease conditions such as  obesity, hypertension, diabetes, cardiovascular disease, or depression should be regularly screened for  common treatable eye diseases and assessed for dementia. Young adults too should be screened for systemic and eye conditions and their risk for dementia evaluated.  Timely intervention can delay or prevent cognitive decline. The study authors said, “information on the age at diagnosis of ophthalmic conditions and the important systemic conditions would be useful for detection or prediction of dementia”.

Reference

1. Shang X, et al. Associations of ophthalmic and systemic conditions with incident dementia in the UK Biobank. Br J Ophthalmol. 2021 Sep 13;bjophthalmol-2021-319508. doi: 10.1136/bjophthalmol-2021-319508.
2. Common eye diseases linked to higher risk for dementia - Medscape - Sep 17, 2021.