Vision impairment a red flag for dementia in older adults

Older adults with impaired vision are at increased risk of developing dementia or cognitive impairment, a study reports.

Researchers conducted a systematic review and meta-analysis of prospective studies to estimate the global burden of dementia associated with vision impairment. They pooled data using random-effects models.

For dementia, 14 studies involving 6,204,777 participants were included. There were 171,394 individuals who had incident dementia over a follow-up that ranged between 4 and 14 years among the studies. Vision impairment was associated with a 47-percent increased risk of developing the neurological disease (relative risk [RR], 1.47, 95 percent confidence interval [CI], 1.36–1.60).

For cognitive impairment, 12 studies comprising 45,065 participants were included. A total of 13,299 cases of cognitive impairment were documented over a follow-up of 3–18 years. Impaired vision conferred a 35-percent risk increase (RR, 1.35, 95 percent CI, 1.28–1.41).

The associations were consistent across methods of vision assessment, length of follow-up, and study quality.

The total number of dementia cases associated with moderate/severe vision impairment in 2016 was 2.1 million (80 percent uncertainty interval, 1.0–3.3), which accounted for 4.7 percent (2.3–7.5) of the global burden of dementia. Economic inequality factored in the burden of vision impairment-related dementia.

The present data suggest that vision impairment, the predominant proportion of which is preventable or treatable, may represent an important modifiable factor for the prevention of dementia.