Summary: Older adults who followed healthier lifestyles not only lived longer, they also spent a greater share of those extra years free from Alzheimer’s disease.
Source: BMJ
A new US study published in The BMJ reports that older adults with healthier habits had longer overall life expectancy and a larger proportion of those additional years free from Alzheimer’s dementia.
While living longer can raise the absolute chance of developing age-related illnesses, the study’s findings indicate that the extra years gained through a healthy lifestyle are not simply years lived with Alzheimer’s disease. Instead, healthier lifestyles were associated with both extended life expectancy and fewer years living with Alzheimer’s.
Worldwide, the number of people living with Alzheimer’s and other dementias is projected to grow substantially, from an estimated 57 million in 2019 to 152 million by 2050. Because of this rising burden, identifying lifestyle factors that can delay dementia onset and increase dementia-free life years is a public health priority.
To explore how lifestyle affects years lived with and without Alzheimer’s, researchers from the United States and Switzerland analyzed data from the Chicago Health and Aging Project (CHAP). The study included 2,449 participants aged 65 and older (average age 76) who had no dementia at baseline and completed detailed diet and lifestyle questionnaires.
Investigators created a healthy lifestyle score from five modifiable factors: adherence to a hybrid Mediterranean-DASH (MIND) diet—emphasizing whole grains, leafy greens and berries and limiting fried foods and red meat; regular late-life cognitive activities such as reading, museum visits, or doing crosswords; at least 150 minutes of moderate to vigorous physical activity per week; not smoking; and light-to-moderate alcohol intake. For each factor that met the healthy criterion, participants received one point, generating a score from 0 to 5 where higher scores indicate a healthier lifestyle.
After adjusting for age, sex, race/ethnicity, and educational level, the researchers estimated life expectancy and the proportion of remaining years lived with Alzheimer’s for people at different lifestyle score levels. At age 65, women with four or five healthy factors had a total life expectancy of 24.2 years compared with 21.1 years for women with zero or one healthy factor. Men aged 65 with four or five healthy factors had a life expectancy of 23.1 years versus 17.4 years for men with zero or one healthy factor.
Importantly, a greater share of those extra years were lived without Alzheimer’s. Among women aged 65 with four or five healthy factors, 10.8% of remaining years (about 2.6 years) were expected to be lived with Alzheimer’s dementia, versus 19.3% (about 4.1 years) for women with fewer healthy factors. For men aged 65, those with higher healthy lifestyle scores spent 6.1% (roughly 1.4 years) of remaining years with Alzheimer’s compared with 12.0% (about 2.1 years) among men with low scores. These differences were even more pronounced at age 85.
The authors caution that this was an observational study and cannot prove causation. Lifestyle measures were self-reported, which may introduce measurement error, and the results should be validated in other populations before broad generalization. Nevertheless, the evidence suggests that promoting healthy behaviors in later life can extend life expectancy while increasing the proportion of years lived free from Alzheimer’s dementia.
The researchers note that the life expectancy estimates produced by this study may help healthcare providers, policy makers, and planners anticipate future service needs, costs, and workforce requirements related to aging and dementia care.
In a linked editorial, a University of Michigan expert highlights the study’s implications for public health policy and ageing populations. She emphasizes the importance of developing and implementing interventions that promote brain health and reduce dementia risk to ease pressure on health systems, caregivers, and families. “Encouraging greater engagement in healthy lifestyles may increase dementia-free years by delaying onset without lengthening years lived with dementia,” the editorial concludes.
Funding: National Institute on Aging, National Institutes of Health
About this lifestyle and dementia research news
Author: Press Office
Source: BMJ
Contact: Press Office – BMJ
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Original Research: Open access.
“Healthy lifestyle and life expectancy with and without Alzheimer’s dementia: population based cohort study” by Klodian Dhana et al. British Medical Journal
Abstract
Healthy lifestyle and life expectancy with and without Alzheimer’s dementia: population based cohort study
Objective
To assess how modifiable lifestyle factors influence life expectancy spent with and without Alzheimer’s dementia.
Design
Prospective, population-based cohort study.
Setting
The Chicago Health and Aging Project (CHAP), United States.
Participants
2,449 men and women aged 65 years and older without dementia at baseline.
Main exposure
A composite healthy lifestyle score based on five factors: a brain-healthy MIND-style diet (top 40% of cohort), engagement in late-life cognitive activities (top 40%), ≥150 minutes/week of moderate-to-vigorous physical activity, no smoking, and light-to-moderate alcohol use (women 1–15 g/day; men 1–30 g/day).
Main outcome
Estimated life expectancy with and without Alzheimer’s dementia for women and men.
Results
Women aged 65 with four or five healthy factors had an estimated life expectancy of 24.2 years (95% CI 22.8 to 25.5), 3.1 years longer than women with zero or one healthy factor (21.1 years, 19.5 to 22.4). Of those remaining years, women with higher healthy lifestyle scores spent 10.8% (2.6 years, 2.0 to 3.3) with Alzheimer’s dementia compared with 19.3% (4.1 years, 3.2 to 5.1) among women with low scores.
For men aged 65, having four or five healthy factors correlated with a total life expectancy of 23.1 years (21.4 to 25.6), versus 17.4 years (15.8 to 20.1) for those with zero or one healthy factor. Men with higher scores spent 6.1% (1.4 years, 0.3 to 2.0) of remaining years with Alzheimer’s, compared with 12.0% (2.1 years, 0.2 to 3.0) for men with low scores.
Conclusion
A healthier lifestyle in later life was associated with longer overall life expectancy and a greater proportion of those years lived without Alzheimer’s dementia. These estimates can inform healthcare planning and policy related to aging populations and dementia care needs.