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The Big Number: If your family has a history of dementia, you are 72 percent more likely than others to develop the disorder

People who have a parent or sibling with dementia are about 72 percent more likely to develop dementia themselves than are those who do not have a family connection to the disorder, according to data detailed at an American Heart Association conference and published in the journal Circulation. But adopting healthy lifestyle behaviors seems to reduce that risk considerably, the study found. For nearly a decade, the researchers tracked 302,239 older adults (ages 50 to 73, and without dementia at the start), specifically monitoring six behaviors: eating a healthy diet (more fruits and vegetables, less processed meat and refined grains), doing at least 150 minutes a week of moderate to vigorous physical activity, sleeping six to nine hours a night, consuming only moderate amounts of alcohol, not smoking and maintaining a healthy weight.

People with a family history of dementia who followed at least three of these healthy behaviors reduced their risk for dementia by 35 percent, compared with those who adhered to fewer healthy behaviors. Among all participants (not just those with dementia in their family history), those who followed all six healthy behaviors cut their dementia risk roughly in half (by 51 percent), compared with people who led a less healthy lifestyle. Dementia affects mostly older adults, but it is not considered a normal part of aging. Symptoms of dementia, which vary from person to person, may include problems with memory (beyond misplaced car keys or forgetting a name), trouble concentrating, becoming confused, getting lost in familiar surroundings and mood changes. In 2020, about 5.8 million Americans had Alzheimer’s, the most common type of dementia, with the Centers for Disease Control and Prevention predicting that number would reach 14 million by 2060. As the American Heart Association president, a neurologist, noted at the conference: “We’ve known for a long time that increasing physical activity and decreasing the amount of time spent in sedentary behaviors . . . can improve one’s heart health. Now we’re seeing that those same activities can also decrease one’s chance of cognitive decline and dementia, and improve brain health.”

— Linda Searing

Alzheimer’s affects 5.8 million people 65 and older. In 2050, that number may be close to 14 million.

Atypical forms of dementia are being diagnosed more often in people in their 50s and 60s.