Alzheimer’s – Reducing your risk … potentially


Alzheimers, the incurable, degenerative, and terminal disease was first described by German psychiatrist and neuropathologist Alois Alzheimer in 1906, hence it was named after him. In its early stages you have an inability to acquire new memories. This is observed as difficulty in recalling recently observed events, then as it advances symptoms include confusion, irritability and aggression, mood swings, language breakdown, long-term memory loss, and the general withdrawal of the sufferer as their senses decline.

Even today the cause is not well understood, but can you do anything as an individual to prevent it, or at least reduce your risk? The good news is that a new study indicates that the answer is “perhaps yes”. Why am I blogging about this? Well because the media has been pumping out a story that there are 7 Steps you can take to prevent Alzheimer’s. The degree of certainty in most stories is not justified, they are claiming that the seven steps will prevent AD, so it is appropriate to clarify the real story here. Examples include articles in the UK’s Independent here, the San Jose Mercury News here, The Huffington Post here, etc… its gone viral.

First the good news, there is indeed a new study that backs the claim, however what you need to be aware of is the assumption being made, it is an assumption that might or might not be correct. What the study does highlight is that over half of all Alzheimer’s disease cases could potentially be prevented through lifestyle changes and treatment or prevention of chronic medical conditions. Note the word ‘potentially’, especially its use in the source study, which was led by Deborah Barnes, PhD, a mental health researcher at the San Francisco VA Medical Center.

Now, lets get right back to that source here and take a look at the actual paper published by Dr Barnes in The Lancet. That paper may be found here, and its summary reads …

At present, about 33·9 million people worldwide have Alzheimer’s disease (AD), and prevalence is expected to triple over the next 40 years. The aim of this Review was to summarise the evidence regarding seven potentially modifiable risk factors for AD: diabetes, midlife hypertension, midlife obesity, smoking, depression, cognitive inactivity or low educational attainment, and physical inactivity. Additionally, we projected the effect of risk factor reduction on AD prevalence by calculating population attributable risks (the percent of cases attributable to a given factor) and the number of AD cases that might be prevented by risk factor reductions of 10% and 25% worldwide and in the USA. Together, up to half of AD cases worldwide (17·2 million) and in the USA (2·9 million) are potentially attributable to these factors. A 10—25% reduction in all seven risk factors could potentially prevent as many as 1·1—3·0 million AD cases worldwide and 184 000—492 000 cases in the USA.

In other words, you can indeed potentially take specific steps that will reduce your risk of developing AD. What the study has found is that the biggest potentially modifiable risk factors for Alzheimer’s disease are, in descending order of magnitude:

  • low education
  • smoking
  • physical inactivity
  • depression
  • mid-life hypertension
  • diabetes
  • mid-life obesity

Taken together, these risk factors are associated with up to 51 percent of Alzheimer’s cases worldwide (17.2 million cases). Barnes comments on this result by observing:

“What’s exciting is that this suggests that some very simple lifestyle changes, such as increasing physical activity and quitting smoking, could have a tremendous impact on preventing Alzheimer’s and other dementias in the United States and worldwide,”

OK, now thats the news … however … I should now explain why I’ve given a lot of emphasis to the word ‘potential’ here. The problem here is that the study makes an assumption that might, or might not, be true. Barnes herself has cautioned that her conclusions are based on the assumption that there is a causal association between each risk factor and Alzheimer’s disease. “We are assuming that when you change the risk factor, then you change the risk,” Barnes said. “What we need to do now is figure out whether that assumption is correct.

Giving up smoking and being more physically active is of course a great idea, there is plenty of evidence that supports that, and so one more potential reason for doing so is that it just might potentially help prevent AD … but only if the assumption being made is correct. So should you take such steps? Yes of course, its your health and so the choice is between doing nothing, or taking steps that will bring you considerable benefit anyway, and so now as an extra bonus, you may also be potentially preventing the onset of AD.

The study results were presented at the 2011 meeting of the Alzheimer’s Association International Conference on Alzheimer’s Disease in Paris, France, and published online on July 19, 2011 in Lancet Neurology.

Its a great discovery, but is also far from being the done deal implied by many press stories, more work is still needed, but hey, give up the smoking anyway, you will be doing yourself a great favor, and even if your brain does not thank you for doing so, your lungs will.

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