Metastudy homes in on 10 strongest risk factors for Alzheimer’s disease
A massive systematic review encompassing hundreds of clinical trials and observational studies has zeroed in on the 10 most common risk factors for Alzheimer’s disease. The researchers suggest avoiding these 10 factors could play a significant role in preventing the onset of Alzheimer’s.
The vast majority of Alzheimer’s disease cases arise from a complex combination of genetics, lifestyle and age. Understanding the environmental factors that amplify one’s risk is key to preventing the disease and this new study, from an international team of researchers, is the largest meta-analysis conducted on the topic to date.
The research included 243 observational studies and 153 randomized controlled trials. One hundred and four modifiable factors were ultimately included in the review, with 10 in particular presenting with what the researchers describe as “Level A strong evidence.”
Those 10 high risk factors for Alzheimer’s are: low levels of education in younger life, low cognitive activity in latelife, high body mass index in latelife, hyperhomocysteinaemia, depression, stress, diabetes, head trauma, hypertension in midlife and orthostatic hypotension.
Several of those risk factors, such as high BMI, diabetes and stress, are unsurprising and have been strongly validated by the targeted studies. A low level of education has also long been correlated with higher rates of age-related dementia, however, it still is unclear whether education actually helps protect from neurodegeneration or whether it simply offers one a cognitive head start.
Commenting on the new research, Rosa Sancho from Alzheimer’s Research UK, says some of these highlighted risk factors are unexpected.
“Intriguingly they found that head trauma and high levels of a compound called homocysteine were associated with the risk of developing Alzheimer’s disease,” says Sancho. “Identifying risk factors like this is an important starting point for further research into ways to limit their impact and help people live for longer free from dementia.”
Hyperhomocysteinaemia, for example, is a condition where one displays higher than normal levels of an amino acid called homocysteine. High homocysteine blood levels don’t generally cause many noticeable symptoms and the condition is often caused by a vitamin B-12 or folate deficiency.
Interestingly, several risk factors commonly linked to Alzheimer’s, such as irregular sleep, smoking and lower levels of physical exercise, were categorized as “Level B weaker evidence.” That is not to say these factors are irrelevant, but the systemic review suggests the strongest data supports the 10 Level A risk factors.
Sancho notes only a third of people believe they can lower their risk of dementia through lifestyle interventions. This means the majority of people may not realize they can reduce the risk of developing age-related cognitive decline by adopting a few lifestyle changes.
“The best way to keep your brain healthy as you age is to stay physically and mentally active, eat a healthy balanced diet, not smoke, drink only within the recommended limits and keep weight, cholesterol and blood pressure in check,” says Sancho.
The new study was published in the Journal of Neurology, Neurosurgery, & Psychiatry.
Source: Alzheimer’s Research UK