Half of worldwide Alzheimer’s disease cases could be prevented by making healthy lifestyle changes that often are associated with preventing other chronic health conditions, researchers assert.

The biggest modifiable risk factors for preventing Alzheimer’s among Americans, according to researchers at the San Francisco VA Medical Center, include physical inactivity, depression, smoking, mid-life hypertension, mid-life obesity, low education and diabetes.

These risk factors are linked with 54% of Alzheimer’s cases in the United States (2.9 million cases) and 51% of cases worldwide (17.2 million cases), said lead researcher Deborah Barnes.

The number of Alzheimer’s cases is expected to triple within the next 40 years, according to the study. A 10% to 25% reduction in all seven risk factors potentially could prevent from 184,000 to 492,000 cases in the U.S., researchers said.

Barnes’ findings were presented at the 2011 Alzheimer’s Association International Conference and published online July 19 in Lancet Neurology.