1 in 3 Cases of Alzheimer's Preventable
As many as 1 in 3 cases of Alzheimer’s disease can be attributed to modifiable risk factors and therefore have the potential to be prevented, according to a new study.
In 2011, it was suggested that as much as half of all worldwide Alzheimer’s cases are preventable.2 According to researchers from Cambridge University, these estimates fail to take risk-factor non-independence into account. The new estimates also consider associations between risk factors.
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In this study, researchers conducted a meta-analysis of studies that analyzed the effects of 7 key risk factors for Alzheimer’s: diabetes, hypertension, obesity, lack of physical activity, smoking, depression, and lack of education.
Using further data collected for the Health Survey for England 2006 to assist in adjusting for risk factor association, researchers calculated the combined population-attributable risk of Alzheimer’s disease.
Note: When researchers treated each of the 7 risk factors independently, then added up the risk at the end, the pooled data suggested that 49.9% of Alzheimer’s cases worldwide were preventable—which was in line with the results of the 2011 study.
However, when researchers accounted for associations between risk factors (eg, diabetes, hypertension, and obesity), the percentage was reduced to 28.2%, or 1 in 3 cases.
Overall, lack of education was found to be the greatest risk factor worldwide; lack of physical activity was the most influential factor in the United States and the United Kingdom.
Researchers added that by reducing the relative risk for each of the 7 risk factors by 10%, as many as 9 million cases of the disease could be prevented by 2050.
Deborah Barnes, PhD, from the University of California, San Francisco, leader of the 2011 study and co-author of the current study concluded, “It’s important that we have as accurate an estimate of the projected prevalence of Alzheimer’s as possible, as well as accurate estimates of the potential impact of lifestyle changes at a societal level.”3
“Our hope is that these estimates will help public health professionals and health policy makers design effective strategies to prevent and manage this disease.”
–Michael Potts
References
Barnes DE, Norton S, Matthews FE, Yaffe K, Brayne C. Potential for primary prevention of Alzheimer's disease: an analysis of population-based data. Lancet. 2014 July 15 [epub ahead of print]. doi:10.1016/S1474-4422(14)70136-X
Barnes DE, Yaffe K. The projected effect of risk factor reduction on Alzheimer's disease prevalence. Lancet. 2011 July 19 [epub ahead of print]. doi:10.1016/S1474-4422(11)70072-2
University of Cambridge. One in three cases of Alzheimer’s worldwide potentially preventable, new estimate suggests [press release]. July 14, 2014. www.cam.ac.uk/research/news/one-in-three-cases-of-alzheimers-worldwide-potentially-preventable-new-estimate-suggests. Accessed July 15, 2014.