Many people assume that their genes largely determine their ultimate risk for dementia. But researchers from the University of Exeter Medical School used a large database of 196,383 European adults to show that lifestyle factors may counteract genetic risk.

The investigators determined genetic risk based on a score that combined data from previous Alzheimer’s disease genetic studies. They considered regular physical activity levels, not smoking, moderate alcohol use, and healthy diet.

Not surprisingly, volunteers with poor lifestyle habits and high genetic risk were three times as likely to develop dementia compared to those with healthy habits and low genetic risk.

However, volunteers with high genetic risk and healthy lifestyle habits had a 32 percent lower dementia risk than those with high genetic risk and poor lifestyle habits.

Another new study confirms that several healthy lifestyle habits practiced together provide better brain protection than engaging in only one or two.

Dr. Klodian Dhana of Rush University Medical Center in Chicago and his colleagues reported on a longitudinal study of 2,351 research volunteers who did not have dementia at the outset of the study.

They found that volunteers who engaged in four or five healthy lifestyle habits (good diet, recommended level of exercise, not smoking, light to moderate alcohol use, or cognitive stimulation) enjoyed a 60 percent lower risk for Alzheimer’s dementia.

These results point to an opportunity for public health interventions because most people engage in unhealthy behaviors.

For example, only about one out of four U.S. adults gets the recommended 150 minutes of exercise each week, and more than 34 million adults smoke cigarettes.