Vision impairment could prove to be a beneficial addition to the Lancet Commission’s life-course model of potentially modifiable dementia risk factors. The estimated population attributable fractions (PAFs) of dementia associated with vision impairment and other dementia risk factors (11 of those included in the Lancet Commission’s life-course model) were calculated to assess and strengthen an existing model of potentially modifiable dementia risk factors, say researchers of study published in JAMA Neurology.
The PAF represents the number of cases of dementia that would potentially be prevented if a risk factor were eliminated. “Since a large majority of vision impairment can be treated with cost-effective but underused interventions, this may represent a viable target for future interventional research that aims to slow cognitive decline and prevent incident dementia” according to the researchers.
Following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines, this population-based, cross-sectional study uses data from the 2018 round of the Health and Retirement Study to expand analyses from March to September of 2021. The study population was a probability sample of US adults aged 50 years and older. The probability sample from the Health and Retirement Study (HRS) included 16,690 participants with the following weighted demographic characteristics: 54.0% women, 52.0% aged 65 years or older, 10.6% Black, 80% White, and 9.2% identified as other.
The 12 dementia risk factors in the PAF model were associated with an estimated 62.4% of dementia cases in the US with the risk factor of hypertension having the highest weighted PAF at 12.4%. “The PAF of vision impairment was 1.8%, suggesting that more than 100,000 prevalent dementia cases in the US could potentially have been prevented through healthy vision,” state investigators.
Limitations of the study include the fact that the meta-analysis that estimated effect sizes for dementia risk factors did not consistently adjust for all other risk factors. Further, researchers note that they were unable to assess whether the elimination of risk factors may be associated with dementia incidence.
Since a large majority of vision impairment is modifiable, investigators note that further investigations are warranted to determine whether interventions to optimize vision can prevent future cases of dementia by slowing cognitive decline.
Ehrlich JR, Goldstein J, Swenor BK, Whitson H, Langa KM, Veliz P. Addition of vision impairment to a life-course model of potentially modifiable dementia risk factors in the US. JAMA Neurol. Published online April 25, 2022. doi:10.1001/jamaneurol.2022.0723