Up to 1 in 5 Dementia Cases May Be Attributable to Vision Impairment

Up to one in five prevalent dementia cases may be attributable to impaired vision, a cross-sectional analysis suggested.

In a study of nearly 2,800 older Americans, the population attributable fraction (PAF) of prevalent dementia from at least one vision impairment was 19% (95% CI 8.2-29.7), reported Jason Smith, ScM, of Johns Hopkins University Bloomberg School of Public Health in Baltimore, and co-authors.

PAFs — the upper limits of dementia attributable to vision impairment, assuming causality — varied across contrast sensitivity, near visual acuity, and distance visual acuity, the researchers said in JAMA Ophthalmology.

Contrast sensitivity impairment had the strongest attributable PAF (15%, 95% CI 6.6-23.6), followed by near acuity (9.7%, 95% CI 2.6-17.0), and distance acuity (4.9%, 95% CI 0.1-9.9) impairments.

“In a nationally representative sample of older U.S. adults, up to 19% of dementia prevalence might have been avoided through prevention and treatment of vision impairments that are largely correctable,” Smith and colleagues wrote.

“Contrast sensitivity was associated with the largest PAF, indicating the total impact of vision impairment on dementia should be quantified using measures beyond just distance visual acuity,” they continued. “Overall, while not establishing a cause-and-effect relationship, these findings support considering vision health in dementia prevention strategies aimed at reducing modifiable risk factors.”

Sensory loss has emerged as an important modifiable dementia risk factor in recent years. A prospective study showed that cataract surgery was tied to a nearly 30% lower risk of dementia in older adults, suggesting that cataract patients may benefit from higher sensory input. In an autopsy study, hearing impairment was linked with neuropathological hallmarks of dementia…….

Read more: https://www.medpagetoday.com/neurology/dementia/111827

Source: Med Page Today