Better heart health may mean lower dementia risk in older people

Older adults with more ideal measures of cardiovascular health were less likely to develop dementia and experience cognitive decline.

This was the main finding of a recent study now published in JAMA that followed 6,626 people aged 65 and over in France for an average of 8.5 years.

It based the cardiovascular health measures on the American Heart Association (AHA) "Simple 7" guide.

The guide recommends: giving up smoking; being physically active; having a diet rich in vegetables, fruit, and fish; having a healthy weight; and managing blood pressure, cholesterol, and blood sugar.

Lead study author Dr. Cecilia Samieri, from the Université de Bordeaux in France, and colleagues explain in their study paper that few researchers have "investigated the combined effect of these risk factors on the risk of dementia and cognitive aging."

Those that have, they observe, have tended to concentrate on the first four "lifestyle" factors — namely, smoking status, physical activity, diet, and weight.

'Optimal levels' of cardiovascular health

The people examined in the research lived in Bordeaux, Dijon, and Montpellier, all in France. None had dementia or a history of cardiovascular disease when they joined the study, which began recruiting in 1999. Their average age was 73.7 years and 4,200 were women.

All of the participants took repeated tests of cognitive ability during the follow-up. In addition, they underwent screening for dementia, and an independent panel of neurologists confirmed any diagnoses.

At the start of the study, the scientists also assessed each individual according to how well they matched the "optimal level" of each of the seven cardiovascular health measures.

They defined the optimal levels of these measures as:

  • never having smoked or having quit for at least 12 months
  • regular physical activity, such as walking at least 8 hours per week or 4 hours per week or more of moderate-intensity sport or leisure activity
  • at least one daily portion of raw vegetables, fresh fruits, and cooked fruits or vegetables and two or more servings per week of fish
  • a body mass index (BMI) under 25
  • total cholesterol under 200 milligrams per deciliter, untreated
  • blood pressure below 120/80 millimeters of mercury, untreated
  • fasting blood glucose under 100 milligrams per deciliter, untreated

At the start of the study, 36.5 percent of people were in the optimal level in 0–2 of the measures, while 57.1 percent achieved optimal levels in 3–4 measures and 6.5 percent achieved 5–7.

Over the follow-up, the panel diagnosed and confirmed 745 cases of dementia.

Brain and heart share risk factors

When they analyzed the results at the end of the study, the researchers revealed that having more optimal levels of cardiovascular health measures was tied to a lower dementia risk and cognitive decline rate.

They conclude that:

"These findings may support the promotion of cardiovascular health to prevent risk factors associated with cognitive decline and dementia."

In discussing the study's limitations, the authors note that because it included mainly white people living in urban settings, the results may not be typical of other groups.

Another limitation that they highlight is the fact that they did not consider changes to individuals' cardiovascular measures over the period of the study.

In a linked editorial, Drs. Jeffrey L. Saver and Mary Cushman comment on these results and those of another investigation, led by the University of Oxford in the United Kingdom, published in the same issue of the journal.

The other study examined healthy young adults for any links between cardiovascular health and measures of brain structure and function that were assessed using state-of-the-art imaging technology.

Those results showed that good cardiovascular health — "already at this early age" — was tied to signs of "more robust" blood circulation and less damage of white matter in the brain.

"Failure to attain optimal cardiovascular health," note Drs. Saver and Cushman, "appears to subtly compromise the fundamental anatomic structure of the brain vascular system in addition to its functional physiology and the integrity of the brain tissue it nourishes."