Alzheimer's: up to 40% of cases are preventable

Alzheimer's disease is the most prevalent form of dementia. It is a neurodegenerative disease in which specific neuropathological changes, such as the accumulation of amyloid-beta plaques and neurofibrillary tangles (TAU proteins) in the brain, lead to progressive loss of neurons and their synaptic connections. This results in worsening cognitive decline.

Twelve risk factors identified
"Up to 40% of dementia cases could be prevented by being aware of and avoiding twelve important risk factors," says dementia researcher Elisabeth Stögmann from MedUni Vienna's Department of Neurology. These include population-wide factors such as access to education and prevailing levels of air pollution, as well as individual risk factors such as lack of exercise, smoking, excess weight, and hypertension. Older adults who are physically active are more likely to maintain their cognitive abilities than those who do not. Several studies have consistently reported an increased risk of dementia associated with vascular and metabolic risk factors such as high blood pressure, high LDL cholesterol levels and obesity in middle age. People who follow a Mediterranean diet (low in meat and dairy, high in fruit, vegetables, and fish) have fewer vascular risk factors and better overall cognitive function. Not smoking, eating fruit and vegetables daily and only drinking alcohol in moderation increases life expectancy and improves health in old age. However, there are other risk factors as well as the physical ones. "We have known for some time that there is a link between social isolation and dementia," adds Stögmann.

Difficult to distinguish from the normal aging process
Increased public awareness of dementia is causing many older people to worry that they are losing their cognitive abilities. People are increasingly turning to specialised memory outpatient clinics for a comprehensive dementia diagnosis. However, since various cognitive functions naturally deteriorate with age, even in the absence of any pathology, it is not always easy to distinguish between normal cognitive aging and pathological aging, and this requires a more detailed examination.

Early detection important
"We now know that plaque deposition in the brain begins ten to 20 years before the onset of obvious clinical symptoms," explains neurologist Elisabeth Stögmann. Consequently, the definition of Alzheimer's disease has evolved into a biological disease continuum, she says. The preclinical phase defines a stage in which early neuropathological changes are present but there are few, if any, detectable cognitive deficits. It is precisely this preclinical phase that is key for achieving targeted prevention, initiating an established drug treatment, enrolling in a clinical trial, and developing disease-modifying therapies. Just as with other diseases, it is important to identify patients who are at risk of cognitive decline as early as possible. "Diagnosing the early stages of Alzheimer's disease, such as mild cognitive impairment, is particularly important," says Stögmann, "and screening techniques that can exclude or confirm pathological cognitive decline with a high degree of certainty play a major role in this".

EU project investigating risk factors
Elisabeth Stögmann, who heads up the Outpatient Clinic for Memory Disorders and Dementia at the Department of Neurology, is carrying out research to identify further risk factors for dementia using various approaches as part of a Horizon 2020 project funded by the European Union. In this project, she is working with European partners, digital health initiatives and patient organisations to advance dementia prevention (https://www.lethe-project.eu/)."There is still a long way to go before we can arrest or even cure Alzheimer's disease or other forms of dementia," says Stögmann, offering a glimpse into the future. No approved causal treatment is currently available, although new study results are eagerly awaited in the coming months.