A significant new review has revealed that vision loss and high cholesterol are emerging as critical risk factors for dementia. The study suggests that addressing these risk factors, alongside 12 previously identified ones, could potentially prevent nearly 50% of dementia cases globally. However, tackling some of these risks can be challenging, and genetics and aging remain the primary contributors to the development of this condition.
“Dementia represents one of the most pressing health challenges we face today,” a leading expert emphasized. “It is crucial to recognize the possibility of reducing the incidence of this debilitating illness.”
A previous version of this review listed 12 modifiable risk factors for dementia, including hearing loss, depression, smoking, high blood pressure, heavy alcohol use, obesity, air pollution, traumatic brain injury, diabetes, social isolation, physical inactivity, and lack of education.
The latest update, involving 27 experts in the field, retains these 12 factors while introducing two additional risks: elevated low-density lipoprotein (LDL) cholesterol in individuals under 65 years and untreated vision loss in older adults.
Researchers included high LDL cholesterol based on comprehensive analyses, including a study tracking nearly 1.2 million UK participants under 65. It found that each increase of 1 millimole per liter (mmol/L) of LDL cholesterol correlated with an 8% rise in dementia occurrences. Another study indicated that LDL levels above 3 mmol/L were linked to a 33% increased risk, particularly notable in midlife individuals.
The correlation between high LDL cholesterol and dementia may stem from excess cholesterol in the brain heightening the risk of strokes, a known dementia trigger. Additionally, cholesterol is associated with the buildup of beta-amyloid plaques, which play a pivotal role in Alzheimer’s disease progression.
Untreated vision loss was recognized as a risk factor following an analysis of 14 studies involving over 6.2 million cognitively healthy older adults, revealing a 47% increased risk of dementia development over an average of 14.5 years. This risk is primarily attributed to conditions like cataracts and diabetes complications. Experts suggest that vision loss may diminish cognitive stimulation, which is believed to enhance the brain’s resistance to dementia.
Using predictive models, researchers estimated that eliminating each of the 14 modifiable risk factors could lead to a significant reduction in global dementia cases. Hearing loss and high cholesterol were identified as the most impactful, each contributing approximately 7% to dementia occurrences, while obesity and excessive alcohol consumption contributed to just 1%. It was estimated that eradicating all risk factors could prevent around 45% of dementia cases.
However, it is crucial to note that correlating these factors with dementia does not imply causation. Experts caution that targeting these risk factors through interventions might not yield the expected decrease in disease prevalence. These findings reflect population averages and do not necessarily apply on an individual basis, as genetics and age predominantly influence dementia risk. Addressing many of these factors, particularly environmental issues such as air pollution and education disparities, requires collective public health strategies rather than solely individual lifestyle changes.
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