Exercise cuts dementia risk by 45%

 From News Medical/Life Sciences

In a recent study published in JAMA Network Open, researchers examined whether physical activity during early adulthood, midlife, or late life is most strongly associated with a reduced risk of developing Alzheimer’s disease or all-cause dementia.

Their findings indicate that higher physical activity in midlife and late life was linked to a 41-45% lower risk of all-cause dementia, with slightly stronger reductions observed in the highest activity quintile (Q5), and similar patterns were observed for Alzheimer’s disease.

Lifestyle and Timing Challenges in Dementia Prevention Research

Dementia poses a major global health challenge, and effective preventive strategies are urgently needed because current drug treatments for Alzheimer’s disease offer only modest benefits, are costly, and may cause side effects. Growing evidence suggests that modifying lifestyle factors could prevent a substantial portion of dementia cases.

Physical activity is among these modifiable factors, especially during midlife. However, it remains unclear when across adulthood physical activity matters most for long-term brain health. Past research has shown that being physically active in midlife or later life is associated with better brain structure, improved cognitive performance, and a lower risk of dementia. 

Physical activity earlier in life may also be beneficial. However, many studies rely on older adults recalling their youthful activity levels, which introduces error and the possibility of reverse causation, especially when cognitive impairment is already present. As a result, the specific life stages at which physical activity has the greatest impact remain uncertain. 

To clarify this issue, researchers used long-term, prospectively collected data from the Framingham Heart Study, which began in the early 1970s. They aimed to determine whether physical activity in early adulthood, midlife, or late life is most strongly linked with reduced dementia risk.

Participant Selection Across Early, Midlife, and Late-Life Stages

Participants were included if they were dementia-free and had physical activity data at a baseline exam corresponding to one of three life stages: early adulthood (ages 26 to 44), midlife (ages 45 to 64), or late life (ages 65 to 88).

The final analytic samples included 1526 early adult, 1943 midlife, and 885 late life participants. All participants provided informed consent, and the study followed established guidelines.

Physical Activity Measurement Using the Activity Index

Physical activity was measured using the Physical Activity Index, which assigns weighted values to hours spent in sleep, sedentary, slight, moderate, and heavy activities. Higher scores indicate greater total activity. Scores were divided into age-specific quintiles for comparison.

Participants were followed until dementia diagnosis, death, or December 31, 2023. Dementia, all-cause or Alzheimer’s disease, was diagnosed through expert consensus using standard diagnostic criteria.

Cox proportional hazards models estimated hazard ratios for dementia risk across physical activity quintiles, adjusting for age, sex, education, body mass index (BMI), smoking, hypertension, diabetes, hyperlipidemia, and apolipoprotein E (APOE) ε4 status.

Additional analyses considered tertiles and quartiles of activity, activity intensity levels, APOE ε4 stratification, and Alzheimer’s dementia specifically.

Dementia Incidence and Early Patterns Across Life Stages

Participants in late life generally had lower education, higher BMI, and more cardiometabolic conditions than younger groups. Throughout follow-up, 567 individuals developed dementia, 4 percent of early adult, 14 percent of midlife, and 26 percent of late life participants.

Across all age groups, participants with lower physical activity had higher mortality. These results emphasize the higher risk of dementia among less active individuals, especially in midlife and late life.

After accounting for demographic and health factors, only higher physical activity during midlife and late life, not early adulthood, was associated with a significantly reduced risk of all-cause dementia.

In both midlife and late life, individuals in the highest activity quintiles had a significantly lower dementia risk than those in the lowest quintile, approximately 40 percent lower, with Q4 and Q5 showing the strongest associations. 

Early adult activity showed no significant association with dementia risk, likely reflecting the small number of dementia cases in this age group.

APOE ε4 Genetics Modify Midlife and Late-Life Activity Effects

APOE ε4 status modified these associations. The interaction between APOE ε4 and physical activity was statistically significant for midlife only, indicating that genetic risk influenced the strength of the association during this period.

Among non-carriers, higher midlife activity was linked to substantially lower dementia risk, while late-life activity predicted reduced risk for both carriers and non-carriers. In ε4 carriers, only the highest late-life activity level, Q5, reached statistical significance. 

Patterns were similar for Alzheimer’s dementia specifically, with the highest level of midlife and late-life activity associated with lower incidence. However, for Alzheimer’s disease in ε4 carriers, the association did not reach statistical significance, a nuance not attributable to insufficient sample size in the late-life group.

Moderate and heavy midlife activity were particularly protective, whereas slight activity showed no benefit. In late life, benefit was observed regardless of activity intensity.

Strengths and Limitations of the Life-Course Physical Activity Approach

The study shows that midlife and late-life physical activity are key periods during which higher activity levels are associated with reduced risk of all-cause and Alzheimer’s dementia.

Midlife benefits were tied to moderate or heavy activity, whereas late-life benefits occurred regardless of intensity. APOE ε4 status influenced these associations, with stronger effects in non-carriers during midlife and more limited effects in carriers until late life.

These findings reinforce the importance of promoting physical activity across adulthood, particularly during midlife, to support cognitive health.

The life course design, extended follow-up, comprehensive adjudication of dementia, and detailed covariate data are significant strengths of this analysis. However, the predominantly European ancestry sample, limited numbers of dementia cases in early adulthood, reliance on self-reported activity at a single time point, inability to assess earlier-life activity, and potential misclassification or survival bias may limit the generalizability of the results.

Overall, the study identifies midlife and late life as critical windows for physical-activity-based dementia prevention.

Journal reference:

• Marino, F.R., Lyu, C., Li, Y. (2025). Physical Activity Over the Adult Life Course and Risk of Dementia in the Framingham Heart Study. JAMA Network Open 8(11), e2544439. DOI: 10.1001/jamanetworkopen.2025.44439, https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2841638

Ultra-processed food linked to big rise in dementia risk

Eating wholegrains, fruit and veg and other unprocessed foods lower the chance of dementia.Getty

From The Age

Regularly snacking on crisps, biscuits and other fatty, sugary foods significantly increases the risk of dementia, a study has shown.

Harvard University found that a diet high in ultra-processed items, which also include ready meals, fizzy drinks, breakfast cereals and cured meats, raised the chance of developing dementia by 58 per cent.

Researchers followed 5000 Americans for 10 years and found those eating the most junk food also had 46 per cent higher risk of developing mild cognitive impairment, the forerunner to dementia.

Processed meats, such as bacon, hot dogs and sliced ham, were found to contribute most to dementia risk.

Prof Cindy Leung, of Harvard’s T.H. Chan School of Public Health, said the study showed that the benefits of switching to healthy foods “extends well beyond our waistline”.

“The good news is we also found the opposite effect for minimally processed food,” she said.

“Those who ate the most minimally processed whole foods, like fruits and vegetables, whole grains, and unprocessed meats, were 41 per cent less likely to develop dementia. [Which means that the junk food eaters have 2.7 times the risk of whole food eaters!]

“This gives us optimism for clear and actionable next steps. Our study shows that eating healthy whole foods is an important behaviour that can protect our minds as we age.”

Although researchers said they could not prove that junk food was driving dementia they added that it was “biologically plausible” and fitted with growing scientific evidence that ultra-processed foods impact brain function.

Dr Alex Henney, an endocrinologist at the University of Liverpool, said that junk foods may drive obesity, Type 2 diabetes and cardiovascular disease, all of which raise the risk of dementia.

Additives such as emulsifiers and preservatives may also drive inflammation, which has also been implicated in dementia.

The study was published in a special issue of The American Journal of Public Health, looking into the harms of ultra-processed foods.

Experts warned that the public was being prevented from making healthy choices because of “aggressive marketing and harmful food environments”.

New research published in the issue found that the ingredients in ultra-processed food were often combined in forms deliberately chosen to engage the brain’s reward systems, making them likely to trigger addictive patterns of eating.

Dr Ashley Gearhardt, professor of psychology, of the University of Michigan, found that quick-release carbs coupled with high fat created the “once you pop, you can’t stop” addictive quality of junk food.

“Real whole food did not trigger an addictive response,” she said. “Nobody is bingeing on that stuff. Nobody is saying ‘apple slices, bet you can’t stop once you start.’

“The number one lever that was pulled was rapidly delivering carbohydrates into the body. That was often complemented by fat.

“This is literally missing from Mother Nature. Our bodies never evolved to get this ‘one-two punch’ in these energy-dense concentrated packages.”

Researchers argued that many of the same corporate strategies used by the tobacco industry were now being employed to keep people addicted to disease-causing food.

They found that many US tobacco companies had bought into the ultra-processed food industry and were using sales tactics similar to those used for cigarettes to sell the products, such as flavour engineering, and creating seemingly “low-fat” versions to retain customers who were concerned about health harms.

“Ultra-processed food is not simply an issue of personal responsibility or individual choice,” said Dr Nicholas Chartres, the lead editorial author and researcher at the University of Sydney and the University of California, San Francisco.

“The evidence increasingly points to a commercial system that has engineered, marketed, and normalised products linked to widespread chronic disease. The public health and government response must reflect that reality.

“The research that has been published adds to a growing body of evidence that these products are associated with chronic disease and that they have addictive characteristics.”

Dementia Donnie

 From Tom Tomorrow

The doomsday bomb

 By Tom Tomorrow

Can you remember these words

 By Dave Whamond

Reading can lower dementia risk by 40%

Public investments that expand access to enriching environments such as libraries may help to reduce the incidence of dementia, the study author said. Photograph: Westend61/Getty Images

From The Guardian

Reading, writing and learning a language or two can lower your risk of dementia by almost 40%, according to a study that suggests millions of people could prevent or delay the condition.

Dementia is one of the world’s biggest health threats. The number of people living with the condition is forecast to triple to more than 150 million globally by 2050, and experts say it presents a big and rapidly growing threat to future health and social care systems in every community, country and continent.

US researchers found that engaging in intellectually stimulating activities throughout life, such as reading, writing or learning a new language, was associated with a lower risk of Alzheimer’s disease, the most common form of dementia, and slower cognitive decline.

The study author Andrea Zammit, of Rush University Medical Center in Chicago, said the discovery suggested cognitive health in later life was “strongly influenced” by lifelong exposure to intellectually stimulating environments.

“Our findings are encouraging, suggesting that consistently engaging in a variety of mentally stimulating activities throughout life may make a difference in cognition. Public investments that expand access to enriching environments, like libraries and early education programs designed to spark a lifelong love of learning, may help reduce the incidence of dementia.”

Researchers tracked 1,939 people with an average age of 80 who did not have dementia at the start of the study. They were followed for an average of eight years. Participants completed surveys about cognitive activities and learning resources during three stages.

Early enrichment, before 18, included the frequency of being read to and reading books, access to newspapers and atlases in the home, and learning a foreign language for more than five years.

Middle-age enrichment included income level at 40, household resources such as magazine subscriptions, dictionaries and library cards and the frequency of activities such as visiting a museum or library. Later-life enrichment, starting at an average age of 80, included the frequency of reading, writing and playing games and total income from social security, retirement and other sources.

In total, 551 participants developed Alzheimer’s disease and 719 developed mild cognitive impairment (MCI) during the study, which was published in Neurology, the medical journal of the American Academy of Neurology.

Researchers compared those with the highest level of cognitive enrichment, the top 10%, with those with the lowest level, the bottom 10%. Of those with the highest level, 21% developed Alzheimer’s. Among those with the lowest, the figure was 34%.

After adjusting for factors such as age, sex and education, researchers found higher scores in lifetime enrichment were associated with a 38% lower risk of Alzheimer’s disease and a 36% lower risk of MCI.

People with the highest lifetime enrichment developed Alzheimer’s disease at an average age of 94, compared with 88 for those with the lowest level of enrichment – more than a five-year delay.

Researchers found people with the highest lifetime enrichment developed MCI at an average age of 85, compared with 78 for those with the lowest level of enrichment – a seven-year delay.

Researchers also looked at participants who died during the study and had autopsies. Those with higher lifetime enrichment had better memory and thinking skills and slower decline prior to death, the study found.

A limitation was that participants reported details about their early and midlife experiences later in life, so may not have remembered everything accurately. The study also did not prove that lifelong learning reduces the risk of dementia, as it only showed an association.

Dr Isolde Radford, a senior policy manager at Alzheimer’s Research UK, who was not involved with the study, said the findings highlighted that dementia was not an inevitable part of ageing.

“This new research shows that staying mentally active throughout life can cut the risk of Alzheimer’s disease by nearly 40%,” she said. “This supports what we already know about the preventive steps people can take to reduce their risk of developing dementia.”

The factors that reduce or prevent dementia are becoming more and more clear:

• Use it or lose it.  Don't just sit there like a pudding watching TV or the internet.  Read, think, learn a language.
• Social contact is important.  Loneliness is lethal.  The authorities should be strongly encouraging meet-ups for older people, like coffee mornings at neighbourhood learning centres.
• Poverty in old age makes things worse because it narrows options available---and the mind.  It might work out cheaper for society to make sure the old can enjoy a rich social and intellectual life than to cut support and face subsequent huge health expenses.
• Omega-3 unsaturated fatty acids are essential, literally.  Don't heat them; they'll disintegrate if they're cooked.  You get them from fish, nuts and seeds, especially walnuts, (ground) linseed, pepitas (hulled pumpkin seed).
• Red and processed meat is bad for dementia (I'll be doing a post on this shortly).  A healthy diet helps keep your brain healthy.
• Exercise is good.  Surprisingly, weight-training seems to help a lot, but even a daily walk makes a difference.