Healthy midlife habits linked to longer dementia-free years

Having normal blood pressure, no diabetes, and not smoking from age 48 to 68, are associated with nearly 13 additional years on average of dementia-free life, a new study shows.

Led by NYU Langone Health researchers, the new work also found that, no matter how many risk factors they had, women lived longer without dementia than men, and that white study participants had more dementia-free years than Black participants.

Published online Aug. 5 in Neurology^® Open Access, the study results underscore the dual impact of the identified midlife risk factors, the presence of which was linked to both accelerated dementia onset and shortened overall dementia-free lifespans.

"Our findings argue that people need to actively avert these factors in midlife as a strategy for preserving brain health for more than a decade," said study senior investigator Josef Coresh, MD, PhD, founding director, Optimal Aging Institute, NYU Langone. "Discovering new ways to delay dementia is crucial with 42 percent of Americans at risk for developing the condition at any time after age 55." Dr. Coresh is also the Terry and Mel Karmazin Professor, Department of Population Health, NYU Langone.

For the new study, the researchers analyzed data in the community-based Atherosclerosis Risk in Communities (ARIC) Study, which started in 1986 and followed participants over decades into late life, measuring midlife vascular risk factors and dementia.

The current study looked at 12,409 people with an average age of 56 who were free of dementia. Participants were assessed for three risk factors: high blood pressure, diabetes, and smoking. They were then followed for an average of 26 years. During that time, 3,008 developed dementia and 5,238 people died without developing dementia. Those who had no risk factors lived without developing dementia nearly 13 years longer than people with the three risk factors (30 years total after the study's start versus 17 years).

The team also sought to determine how cardiovascular risk factors in midlife influenced dementia-free survival across demographics. Women with all three risk factors lived an average of 18.1 years from the start of tracking without developing dementia, compared to 16.6 years for male study participants. White participants with all three risk factors lived an average of 19.6 years without developing dementia, compared to 16 years for Black participants.

"These results suggest that vascular risk reduction may benefit all groups, but that certain populations, such as Black adults, may especially benefit from targeted prevention efforts," Dr. Coresh added. "Hopefully, these results will encourage people to stop smoking and watch their vascular health closely from age 48 on."

Importantly, the study was not designed to prove that avoiding these vascular risk factors caused the observed delay in dementia - only that they were associated with each other. Another limitation of the study was that the risk factor measurement was performed just once, so changes over time were not captured.

This study was supported by National Institutes of Health (NIH) grants K24HL152440 and K01DK138273, and the ARIC study was funded by grants NIH U01HL096812, U01HL096814, U01HL096899, U01HL096902 and U01HL096917.