A 25% reduction in seven risk factors could potentially prevent as many as three million cases of Alzheimer’s disease worldwide.
PARIS—As many as half of Alzheimer’s disease cases worldwide are potentially preventable by taking the following measures—quitting smoking, increasing physical activity, enhancing mental activity, controlling blood pressure and diabetes, and managing obesity and depression—according to research that was presented at the 2011 Alzheimer’s Association International Conference and published simultaneously in the July 18 online Lancet Neurology. Furthermore, a 25% reduction in all seven of these risk factors could prevent as many as three million cases of Alzheimer’s disease worldwide.
“Given the current absence of disease-modifying treatments, as well as increasing awareness that symptoms develop over many years or even decades, there has been growing interest in identification of effective strategies for prevention of Alzheimer’s disease,” reported Deborah Barnes, PhD, an Assistant Adjunct Professor of Psychiatry, University of California, San Francisco (UCSF), and Kristine Yaffe, MD, Professor of Psychiatry, Neurology, and Epidemiology, UCSF. “Observational studies have identified a wide range of potentially modifiable risk factors for Alzheimer’s disease and dementia.”
Risk Factor Reduction in Alzheimer’s Disease
The authors reviewed the evidence related to predisposing factors for Alzheimer’s disease, including cardiovascular risk factors, psychosocial factors, and health behaviors. They identified seven potentially modifiable risk factors—low educational attainment, smoking, physical inactivity, depression, midlife obesity, midlife high blood pressure, and diabetes.
Using data from recent systematic reviews and meta-analyses, the researchers estimated the number of preventable Alzheimer’s disease cases that could be achieved by reducing the burden of each of these factors, with the goal of identifying interventions that might be able to help delay the development of the disease.
Overall, the findings suggest that these seven preventable risk factors potentially contribute to as many as half of Alzheimer’s disease cases worldwide (17.2 million) and in the United States (2.9 million). Furthermore, according to Drs. Barnes and Yaffe, a 10% reduction in all seven risk factors could reduce the number of cases by 1.1 million worldwide and by 184,000 in the United States.
Risk Factors for Alzheimer’s Disease
The authors predict that low educational attainment contributes to the largest proportion (19%: 6.5 million) of Alzheimer’s disease cases worldwide, and smoking contributes to the second highest number (14%: 4.7 million); physical inactivity contributed to the third largest proportion (13%: 4.3 million) of cases worldwide and the largest number of cases in the United States (21%: 1.1 million).
“What really mattered was how common the risk factors were in the population,” said Dr. Barnes. “In the United States, about a third of the population is sedentary, so a large number of Alzheimer’s disease cases are potentially attributable to physical inactivity.
Worldwide, low education was more important, because so many people throughout the world are illiterate or are not educated beyond elementary school. Smoking also contributed to a large percentage of cases, because it is unfortunately still really common.”
The study findings suggest that although treatments for Alzheimer’s disease remain in the investigational stage, there are a number of ways in which people can lower their risk for the disease. Such steps could have a dramatic effect, and include smoking cessation initiatives and public health initiatives to increase physical activity levels throughout life.