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Healthy living tied to a longer life and dementia-free old age

Preventing Alzheimer’s dementia through lifestyle modifications has gained considerable attention in recent years owing to growing evidence that they help to slow cognitive decline and potentially reduce the risk of Alzheimer’s dementia. In addition to attenuating dementia risk, successful modification of these lifestyle factors is also associated with an increased life expectancy. However, with greater life expectancy, many more people will attain older ages, and because the risk of dementia increases exponentially with increasing age, they will be predisposed to the risk of cognitive impairment and Alzheimer’s dementia. Until recently, it has not been clear whether extending life just increases the number of years spent with dementia. A new study created to address that question was published online on April 13 in the British Medical Journal.

This study was performed within the Chicago Health and Aging Project (CHAP), a prospective population based cohort study designed to assess the risk factors of Alzheimer’s dementia in the general population. Current analysis included 2449 men and women aged 65 years and older. Their lifestyles were assessed based on five modifiable lifestyle factors: a diet for brain health (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay—MIND diet score in upper 40% of cohort distribution), late life cognitive activities such as reading, visiting museums, and playing games like cards, checkers, crosswords, or puzzles (composite score in upper 40%), moderate or vigorous physical activity (≥150 min/week), no smoking, and light to moderate alcohol consumption (women 1-15 g/day; men 1-30 g/day). Cognitive functions were assessed using a battery of 17 different tests which results were further reviewed by board certified neuropsychologists and neurologists. An impairment in two or more functions including memory, language, orientation, attention, and perception on cognitive performance tests and a loss of cognitive function determined by the neurologist were required to diagnose dementia.

The results have shown that a healthy diet, physical activity, and cognitive training help extend life expectancy — and those extra years are more likely to be dementia-free in both genders. In fact, women aged 65 with four or five healthy factors had a life expectancy of 24.2 years (95% confidence interval 22.8 to 25.5) and lived 3.1 years longer than women aged 65 with zero or one healthy factor (life expectancy 21.1 years, 19.5 to 22.4). Of the total life expectancy at age 65, women with four or five healthy factors spent 10.8% (2.6 years, 2.0 to 3.3) of their remaining years with Alzheimer’s dementia, whereas women with zero or one healthy factor spent 19.3% (4.1 years, 3.2 to 5.1) with the disease. Men aged 65 with four or five healthy factors had a total life expectancy of 23.1 years (21.4 to 25.6), which is 5.7 years longer than men aged 65 with zero or one healthy factor (life expectancy 17.4 years, 15.8 to 20.1). Of the total life expectancy at age 65, men with four or five healthy factors spent 6.1% (1.4 years, 0.3 to 2.0) of their remaining years with Alzheimer’s dementia, and those with zero or one healthy factor spent 12.0% (2.1 years, 0.2 to 3.0) with the disease.

Reference: https://www.bmj.com/content/377/bmj-2021-068390

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