A study suggests that living a healthy lifestyle may be critical to prevent Alzheimer’s and extending life expectancy.
How does a healthy lifestyle prevent Alzheimer’s?
The number of people living with Alzheimer’s, and other dementias, is projected to treble worldwide by 2050, from an estimated 57 million in 2019 to 152 million in 2050. A healthy lifestyle—which is classified as an individual who partakes in adequate exercise, cognitive engagement, and a healthy diet—may prevent Alzheimer’s and extend life expectancy.
Additionally, reaching older ages is associated with a higher risk of Alzheimer’s. So, although a healthier lifestyle may prevent Alzheimer’s dementia to a certain extent, it may also increase the years spent with the disease.
This study was published in the journal BMJ.
How did scientists investigate this further?
To examine this lesser-known issue further, a team of US and Swiss researchers have analysed the potential impact of a healthy lifestyle on the number of years spent living both with and without Alzheimer’s.
The study analyses data from 2,449 participants aged 65 years and older (average age 76), with no history of dementia, within the Chicago Health and Ageing Project (CHAP).
Participants completed detailed diet and lifestyle questionnaires and a healthy lifestyle score was developed based on a hybrid Mediterranean-DASH Diet (a diet rich in whole grains, green leafy vegetables, and berries and low in fast/fried food, and red meats), late-life cognitively stimulating activities, at least 150 minutes a week of physical activity, not smoking, and low to moderate alcohol consumption. Cognitive activities included reading, visiting a museum, or doing crosswords.
For each lifestyle factor, participants received a score of 1 if they met the criteria for healthy, and 0 if they did not. Scores from five lifestyle factors were totalled to generate a final score ranging from 0 to 5—the higher the score, the greater indication that the participant led a healthier lifestyle.
What did the results reveal?
After taking into account other potentially influential factors, including age, sex, ethnicity, and education, the researchers discovered that the total life expectancy at age 65 in women and men with a healthy lifestyle – on average – was 24.2 and 23.1 years. However, for women and men with a less healthy lifestyle, the study revealed that their life expectancy was shorter– 21.1 and 17.4 years.
For women and men with a healthy lifestyle, 10.8% (2.6 years) and 6.1% (1.4 years) of the remaining years were lived with Alzheimer’s respectively, compared to 19.3% (4.1 years) and 12.0% (2.1 years) for study participants with a less healthy lifestyle, suggesting that healthier choices can prevent Alzheimer’s.
What limitations were established within this study?
Furthermore, researchers observed that at age 85, these differences in lifestyles were even more notable, and while the study was population-based with long-term follow-up, this was an observational study, and as such, a cause cannot be established.
Additionally, scientists observed further limitations, for example, lifestyles were self-reported, which leaves possibly for measurement error, and the estimates provided in this study should not be generalised to other populations without additional research and validation.
Researchers said: “The life expectancy estimates presented here could help health professionals, policymakers, and stakeholders to plan future healthcare services, costs, and prevent Alzheimer’s.”
In a linked editorial, a University of Michigan researcher highlighted: “[The study’s] important implications for the wellbeing of ageing populations and for related public health policies and programmes.”
Scientists argued that the development and implementation of intervention programmes to prevent Alzheimer’s disease and other dementias is critically important in global efforts to reduce pressure on stressed healthcare systems, healthcare workers, and both paid and unpaid carers.
However, the researchers concluded: “This investigation suggests that a prolonged life expectancy owing to a healthy lifestyle is not accompanied by an increased number of years living with Alzheimer’s dementia.
“Promoting greater engagement in healthy lifestyles may increase dementia-free life years– by delaying the onset of dementia without extending life years spent with dementia.”
