An updated report from the Lancet Commission on dementia prevention adds two new risk factors for dementia: vision loss and cholesterol.
The Lancet Commission on dementia prevention and intervention, a global project that gets scientists to review the evidence for risk factors of dementia every few years, has released an update to its 2020 report on dementia risk factors. And it includes two new items: vision loss and high cholesterol, bringing the total number of dementia risk factors to 14.
The new report and its 2020 predecessor build on the commission’s original 2017 report, and all are meta-analyses — a statistical combination of results from various studies that examine dementia risk, prevention, and care. The risk factors previously outlined are access to education, head injury, physical inactivity, smoking, excessive alcohol consumption, hypertension, obesity, diabetes, hearing loss, depression, infrequent social contact, and air pollution.
The report notes that as we live longer, the number of people living with dementia will continue to rise. It also explains that there is now an increasing body of evidence to suggest that low-density lipoproteins or LDL cholesterol fall under the category of cardiovascular risk factors (along with hypertension, smoking, and diabetes), which may influence the development of dementia.
Untreated vision loss is cited as a risk factor for dementia, specifically “cortical blindness” – which is vision loss that isn’t caused by problems with the eyes.
While scientists still have yet to determine the cause(s) behind neurodegenerative dementias like Alzheimer’s, research, including the previous Lancet reports, has established that by controlling risk factors like these, as many as 2/5 of all dementia cases could be prevented on a population-wide scale.
However, many risk factors for dementia, such as obesity, are not easy to modify without systemic change. There is also the issue of causation: A problem – such as heart disease, for instance – that results from high LDL cholesterol, may also increase the risk of dementia, prompting the question: ‘which one puts the patient at more risk for developing dementia?’
The most glaring issue, however, is that the risk factors included in the study are not specific to the disease.
“We didn’t say they are all easy,” Dr. Gil Livingston, co-author of the study, told Being Patient. Livingston pointed to the heart of the report, “These findings provide hope.”
Critics of the updated report point to this difficulty of demonstrating how addressing the risk factors reverses their impact on the individual’s overall health and reduces their risk of developing the disease. With regard to depression, for example, not all patients have been shown to respond to psychotherapy.
Livingston also highlighted a study in the report that demonstrated that treatment for depression with pharmacology therapy, psychotherapy, or both, showed a reduced risk for developing dementia than those whose depression went untreated. He recognized that these treatments for depression are not guaranteed to be effective.
Lisa Power is a graduate of the Columbia University Graduate School of Journalism.
