Heart-healthy lifestyle in old age tied to lower dementia risk

Older adults who take care of their heart may be less likely to develop dementia than people who do not focus on heart health, a French study suggests. 

Researchers focused on seven recommendations from the American Heart Association for optimal cardiovascular health: not smoking; regularly exercising; routinely eating fish, fruits and vegetables; avoiding excess weight; and keeping blood pressure, blood sugar and cholesterol levels within a healthy range. 

For an average of 8.5 years, they followed 6,626 people age 65 or older who did not have dementia at the start. During the study, 745 people, or about 11 per cent, developed dementia. 

With each additional heart-healthy recommendation they met, people were 10 per cent less likely to develop dementia, researchers found. 

“Importantly, while achieving the seven cardiovascular health factors at optimal levels is certainly the ideal target, this study shows that any additional factor at optimal level decreases the risk of dementia,” said study leader Cecilia Samieri of the University of Bordeaux and the INSERM population health research centre in Bordeaux. 

Following more recommendations was also associated with higher scores on cognitive tests, indicating a healthier brain, researchers report in JAMA. 

Both the heart and brain need adequate blood flow. But blood vessels can narrow and harden over time, increasing the risk of heart attacks, strokes and cognitive decline. 

This type of blood vessel damage, known as atherosclerosis, can be minimised by a healthy lifestyle and by keeping blood pressure, blood sugar and cholesterol levels in safe ranges. 

High blood pressure, cholesterol and blood sugar can damage blood vessels, triggering complications that reduce blood flow to the brain. 

Even when people did not hit optimal targets for cardiovascular health, they could still benefit from the attempt, Samieri said by e-mail. 

“From a pragmatic and public health perspective, promoting change in cardiovascular health from poor to intermediate levels may be more achievable and have a greater population-level effect than the more challenging change from poor to optimal levels,” Samieri said. 

The study cannot prove that lifestyle changes directly impact cardiovascular health or the risk of dementia and cognitive decline. Another limitation is that researchers only measured cardiovascular health at the start of the study. It is possible this changed over time in ways that influenced participants’ brain health. 

Still, a separate study in JAMA looking at the effect of the same seven factors on cardiovascular health found that younger adults who achieved optimal heart health had fewer changes in their brains with the potential to lead to cognitive problems down the line.

The study focused on young people “because we thought that these changes in the blood vessels may occur... before significant damage had occurred to the brain”, said senior author Paul Leeson of the University of Oxford in the UK.

“We were able to show that there are differences in the blood vessels related to levels of different risk factors and that these differences are evident in young adulthood.”

This study included 125 participants, age 25 on average. For each additional recommendation for optimal heart health they followed, subjects had a greater density of blood vessels in the brain and healthier blood vessels.

Among 52 participants who had blood flow in the brain measured, the volume of blood pumping through the brain increased with each additional optimal heart health recommendation they achieved.