Summary: Older adults with visual impairments are 1.3 times more likely to develop mild cognitive impairment, often considered a precursor to Alzheimer’s disease, than those with no significant vision loss.
Source: Anglia Ruskin University
Older people with vision loss are significantly more likely to suffer mild cognitive impairment, which can be a precursor to dementia, according to a new study published in the journal Ageing Clinical and Experimental Research.
The research by Anglia Ruskin University (ARU) examined World Health Organisation data on more than 32,000 people and found that people with loss in both near and far vision were 1.7 times more likely to suffer from mild cognitive impairment.
People with impairment of their near vision were 1.3 times more likely to suffer from mild cognitive impairment than someone with no vision impairment.
However, people who reported only loss of their far vision did not appear to have an increased risk.
Dr Lee Smith, Reader in Physical Activity and Public Health at ARU, said: “Our research shows for the first time that vision impairment increases the chances of having mild cognitive impairment. Although not everyone with mild cognitive impairment will go on to develop it, there is a likelihood of progression to dementia, which is one of the major causes of disability and dependency in the older population.”
Co-author Shahina Pardhan, Director of the Vision and Eye Research Institute at ARU, said: “Research now needs to focus on whether intervention to improve quality of vision can reduce the risk of mild cognitive impairment, and ultimately dementia. More work needs to be done to examine any possible causation, and what the reasons might be behind it.”
The researchers examined population data from China, India, Russia, South Africa, Ghana and Mexico from the WHO’s Study on Global Ageing and Adult Health (SAGE). The overall prevalence of mild cognitive impairment was 15.3% in the study sample of 32,715 people, while around 44% of the total number of people surveyed had vision impairment.
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Source: Anglia Ruskin University Contact: Jamie Forsyth – Anglia Ruskin University Image: The image is in the public domain
The association between objective vision impairment and mild cognitive impairment among older adults in low- and middle-income countries
The association between visual impairment and mild cognitive impairment (MCI) has not been investigated to date. Thus, we assessed this association among older adults from six low- and middle-income countries (LMICs) (China, India, Ghana, Mexico, Russia, and South Africa) using nationally representative datasets.
Cross-sectional, community-based data from the WHO Study on global AGEing and adult health (SAGE) were analyzed. Visual acuity was measured using the tumbling ElogMAR chart, and vision impairment (at distance and near) was defined as visual acuity worse than 6/18 (0.48 logMAR) in the better-seeing eye. The definition of MCI was based on the National Institute on Aging-Alzheimer’s Association criteria. Multivariable logistic regression was conducted.
Data on 32,715 individuals aged ≥ 50 years [mean (SD) age 62.1 (15.6) years; 51.2% females] were analyzed. Compared to those without far or near vision impairment, those with near vision impairment but not far vision impairment (OR = 1.33; 95% CI = 1.16–1.52), and those with both far and near vision impairment (OR = 1.70; 95% CI = 1.27–2.29) had significantly higher odds for MCI. Only having far vision impairment was not significantly associated with MCI.
Visual impairment is associated with increased odds for MCI among older adults in LMICs with the exception of far vision impairment only. Future longitudinal and intervention studies should examine causality and whether improvements in visual acuity, or early intervention, can reduce risk for MCI and ultimately, dementia.