Activating your brain while sitting helps reduce dementia risk
Research in the American Journal of Preventive Medicine showing that not all sedentary behaviors are equal is poised to inform dementia prevention strategies
March 26, 2026 - New research distinguishing between passive and mentally active sitting in association with dementia has found that adults who engaged in extended durations of mentally passive sedentary behaviors had a higher risk of dementia. Replacing passive with mentally active sedentary behaviors was shown to reduce the risk of dementia onset in later life. The study in the American Journal of Preventive Medicine, published by Elsevier, has the potential to inform public health guidelines and preventive strategies to reduce dementia.
Globally, populations are aging. Dementia is the third highest cause of mortality and the seventh largest cause of disability among older adults globally. It is a prevalent age-related condition affecting many adults’ quality of life, including their families and carers. Prevention is important, and a key part of this involves identifying modifiable risk factors.
It was previously thought that all sedentary behaviors were associated with a higher risk of developing dementia. However, in recent studies, researchers found that mentally passive sedentary behaviors (such as watching TV) increased the risk of depression, while mentally active sedentary behaviors (such as reading and office work) appeared to be protective.
Most adults spend about 9-10 hours per day sitting. Previous research has shown that extended, uninterrupted sitting is a risk factor for cardiovascular disease, type 2 diabetes, and depression. It has also been associated with dementia.
This is the first study to distinguish between passive and mentally active sitting in association with dementia.
Lead investigator Mats Hallgren, PhD, Department of Public Health Sciences, Karolinska Institute, Sweden, and Baker-Deakin Department of Lifestyle and Diabetes, Institute for Physical Activity and Nutrition (IPAN), Deakin University, Australia, notes, “While all sitting involves minimal energy expenditure, it may be differentiated by the level of brain activity. How we use our brains while we are sitting appears to be a crucial determinant of future cognitive functioning and, as we have shown, may predict dementia onset.”
Researchers analyzed data from a longitudinal study of 20,811 adults aged 35-64 years followed over 19 years (1997-2016). The baseline survey included questions about sedentary behaviors, physical activity, and other behaviors associated with dementia. Incident dementia was identified by linking the data of the 1997 survey with the Swedish National Patient Register and the Swedish Cause of Death Register.
Utilizing various statistical models, investigators examined the associations with dementia of (statistically) substituting passive with mentally active sedentary behaviors. “The prospective study design allowed us to establish the direction of these relationships and infers but does not establish causality. Controlled trials are needed to confirm these important observational study findings,” notes Dr. Hallgren.
The study’s main findings are as follows:
- Mentally active sedentary behavior was associated with a reduced risk of developing dementia among middle-aged and older adults.
- Increasing time spent in mentally active sedentary behavior was associated with a significant reduction in dementia risk while maintaining the levels of passive sedentary behavior, light and moderate-to-vigorous physical activity.
- Replacing the amount of time spent in mentally passive sedentary behavior for equivalent durations of mentally active sedentary behavior was also associated with a reduction in the risk for developing dementia.
Given the extensive survey method used to collect these data (3,600 cities and villages across Sweden), the investigators believe the findings are likely generalizable to a wider global population.
Dr. Hallgren concludes, “Sedentary behavior is a ubiquitous but modifiable risk factor for many health conditions, including dementia. Our study adds the observation that not all sedentary behaviors are equivalent; some may increase the risk of dementia, while others may be protective. It is important to remain physically active as we age, but also mentally active—especially when we are sitting.”
Journal
American Journal of Preventive Medicine
Method of Research
Data/statistical analysis
Subject of Research
People
Article Title
Mentally Active Versus Passive Sedentary Behavior and Risk of Dementia: 19-Year Cohort Study
Article Publication Date
26-Mar-2026
Preparing a home cooked meal at least once a week may cut older people’s dementia risk by 30%
This risk may be 70% lower in novice cooks with few culinary skills, study suggests
BMJ Group
Preparing a home cooked meal at least once a week may cut older people’s risk of dementia by 30%, suggests research published online in the Journal of Epidemiology & Community Health.
And this risk may be 70% lower in older novice cooks with few culinary skills, the findings indicate.
Over the past few decades, people have increasingly come to rely on restaurants, takeaways, and frozen food rather than cooking their meals at home, note the Japanese researchers.
But for older people, meal preparation is not only an important source of physical activity, but also cognitive stimulus, they add.
As such, they wanted to find out if the frequency of home cooking might be associated with the incidence of dementia and if this might depend on the level of cooking skills.
They drew on 10,978 participants, aged at least 65, from the Japan Gerontological Evaluation Study, whose cognitive health was tracked for 6 years up to 2022.
A fifth of the participants were aged 80+ and half were women. A third had fewer than 9 years of education, and 40% had an annual income of less than 2 million yen (under £10,000/US$ 12,500). More than half were retired.
Participants filled in questionnaires on how often they cooked meaals from scratch at home, ranging from never to more than 5 times a week, as well as the extent of their culinary competence. This was assessed on 7 skills, ranging from the ability/inability to peel fruit and vegetables to the ability/inability to make stews.
Around half of the participants cooked at least five times a week, while more than a quarter didn’t. Women and those who were experienced cooks tended to cook more meals at home than men and those who were inexperienced cooks.
Cases of dementia were ascertained from data in the public insurance system, which captures functionally significant cognitive impairment requiring care.
During the tracking period, 1195 people developed dementia (cumulative incidence 11%); 870 died and another 157 moved away before developing dementia.
Analysis of the data showed that greater cooking frequency was associated with a lower risk of dementia in both men and women, but differed according to the extent of culinary competency.
Cooking from scratch at least once a week was associated with a 23% lower risk of dementia in men and a 27% lower risk in women than cooking less than once a week.
And for those with few cooking skills, cooking a meal from scratch at least once a week was associated with a 67% reduction in the risk of dementia.
While a high degree of culinary competency was also associated with a lower risk of dementia, cooking frequency didn’t reduce the risk of dementia further.
These findings held true after accounting for potentially influential factors, such as lifestyle, household income, and years of education, and they were independent of other activities positively associated with cognitive reserve, such as crafting, volunteering, and gardening.
This is an observational study, and as such, no firm conclusions can be drawn about cause and effect. And cases of mild dementia would not have been included in the registry data and the classification of cooking skills may not have differentiated between those cooking simple meals because they didn’t like cooking and those unable to cook, the researchers highlight.
The findings may not apply more widely because what food is eaten, and how it is prepared, vary from culture to culture, they add.
Nevertheless, they conclude: “Creating an environment where people can cook meals when they are older may be important for the prevention of dementia.”
Method of Research
Observational study
Subject of Research
People
Article Title
Home cooking, cooking skills and dementia requiring long-term care: a population-based cohort study in Japan
Article Publication Date
24-Mar-2026
Severe infections may raise dementia risk, study finds
Finnish registry study finds that infections like cystitis and bacterial disease are linked to higher dementia risk independently of other coexisting conditions
image:
Associations between dementia-related diseases. For clarity, the figure illustrates associations between 14 of the 29 dementia-related diseases identified in the study (all 29 diseases are shown in Fig 4 of the paper in PLOS Medicine).
view moreCredit: Sipilä PN, et al., 2026, PLOS Medicine, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
Severe infections increase the risk of dementia independently of other coexisting illnesses, according to a new study published March 24th in the open-access journal PLOS Medicine by Pyry Sipilä of the University of Helsinki, Finland, and colleagues.
Severe infections have been linked to an increased risk of dementia. However, it has been unclear whether this association is explained by other coexisting, non-infectious diseases that predispose people to both infections and dementia.
In the new study, researchers used nationwide Finnish health registry data covering more than 62,000 individuals aged 65 or older who were diagnosed with late-onset dementia between 2017 and 2020, along with more than 312,000 matched dementia-free controls. Taking a broad approach, they examined all hospital-treated diseases recorded during the previous twenty years, identifying 29 diseases that were robustly associated with increased dementia risk. Nearly half (47%) of dementia cases had at least one of the 29 identified diseases before their diagnosis.
Of those diseases, two were infections: cystitis (a urinary tract infection) and bacterial infection of an unspecified site. Among the non-infectious diseases, the strongest associations with dementia were seen for mental disorders due to brain damage or physical disease, Parkinson’s disease, and alcohol-related mental and behavioral disorders.
When the researchers then adjusted for all 27 non-infectious dementia-related diseases identified, the association between both infections and dementia remained largely intact. Less than one-seventh of the excess dementia risk among individuals with hospital-treated cystitis or bacterial infections was attributable to pre-existing conditions. The link between infections and dementia was even stronger for early-onset dementia (diagnosed before age 65), where five types of infection—including pneumonia and dental caries—were associated with elevated risk.
The study was limited by the lack of baseline cognitive assessments and clinical examination data before dementia diagnoses, as well as a lack of data on infection treatments.
“Overall, our findings support the possibility that severe infections increase dementia risk; however, intervention studies are required to establish whether preventing or effectively treating infections yields benefits for dementia prevention,” the authors say.
The authors add, “We found 27 diverse severe, hospital-treated diseases that were robustly associated with an increased risk of dementia. Two of these diseases were infections, namely urinary tract infections and unspecified bacterial infections.”
“In our study, dementia-related infections occurred on average 5 to 6 years before dementia diagnosis. Given that the development of dementia often takes years or even decades, these findings suggest that severe infections might accelerate underlying cognitive decline. However, as these findings were observational, we cannot exclude the possibility that some unmeasured confounding factors might also have affected our findings. Thus, we cannot prove cause and effect.”
“Ideally, intervention trials should examine whether better infection prevention helps reduce dementia occurrence or delay the onset of this disease.”
In your coverage, please use this URL to provide access to the freely available paper in PLOS Medicine: https://plos.io/4qY5nix
Citation: Sipilä PN, Korhonen K, Lindbohm JV, Kivimäki M, Martikainen P (2026) The role of noninfectious comorbidities in the association between severe infections and risk of dementia in Finland: A nationwide registry study. PLoS Med 23(3): e1004688. https://doi.org/10.1371/journal.pmed.1004688
Author countries: Finland, United States of America, United Kingdom, Germany
Funding: see manuscript
Journal
PLOS Medicine
Method of Research
Observational study
Subject of Research
People
