„Passive“ Bildschirmzeit kann das Demenzrisiko erhöhen | Geistig aktives versus passives Bewegungsmangelverhalten und Demenzrisiko: 19-jährige Kohortenstudie

Selections from the article and interview:

> Watching television and other “mentally passive” sedentary behaviors are linked to a higher risk of developing dementia, while more mentally engaging activities such as crossword puzzles appear to offer some protection, according to a new study.
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>The findings add nuance to what we know about brain health and aging, and they suggest that cognitive activity is important alongside physical activity.
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>…
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>CNN: What did this study examine about sedentary behavior, and what were its conclusions?
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>Dr. Leana Wen: This study, published in the American Journal of Preventive Medicine, followed more than 20,000 adults in Sweden over nearly two decades to examine how different types of sedentary behavior were associated with the risk of developing dementia. Participants were between 35 and 64 years old at the beginning of the study. They reported how much time they spent sitting and what kinds of activities they were doing during that time. This data was correlated with later dementia diagnosis, which was made in 569 individuals during the nearly 20-year study period.
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>The researchers made an important distinction between mentally passive and mentally active sedentary behaviors. They found that individuals who spent more time in mentally passive activities had a significantly higher risk of developing dementia later. By contrast, time spent in mentally engaging activities while sitting was associated with a lower risk.
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>They also modeled what might happen if people changed their behavior. Replacing one hour of mentally passive sedentary time with one hour of mentally active sedentary behavior was associated with about a 7% reduction in dementia risk. Adding an hour of mentally active sedentary behavior overall was associated with a 4% reduction, and combining mental engagement with physical activity showed even greater benefit, with 11% lower risk of developing dementia.
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>…
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>CNN: What is the key takeaway for people who are worried about cognitive decline?
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>Wen: The key takeaway is that small, everyday choices can make a difference over time. People should aim to reduce prolonged periods of passive behavior and replace them, when possible, with activities that engage the mind.
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>At the same time, we should remember that brain health is closely tied to overall health. That means staying physically active, maintaining good cardiovascular health, avoiding smoking, following a nutritious diet and getting adequate sleep. Based on decades of research, it’s the combination of these habits practiced over years that helps support cognitive function over the long term.

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Link to journal article: [Mentally Active Versus Passive Sedentary Behavior and Risk of Dementia: 19-Year Cohort Study](https://www.ajpmonline.org/article/S0749-3797(26)00060-7/fulltext)

Abstract:

>Introduction
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>Sedentary behavior (sitting/reclining) has been associated with depression in adults, but the relationship with dementia remains unclear. To address this, associations of mentally passive (e.g., TV-viewing) and mentally active (e.g., office work) sedentary behaviors with incident dementia were examined, including how theoretically replacing mentally passive sedentary behavior with mentally active sedentary behavior, light and moderate-to-vigorous physical activity impacts incident dementia risk.
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>Methods
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>Data originate from the Swedish National March Cohort, including 20,811 adults aged 35–64 years (baseline, 1997). Incident dementia was identified through a linkage (2016) with the Swedish National Patient Register and the Swedish Cause of Death Register. Passive and mentally active sedentary behaviors as well as light and moderate-to-vigorous physical activity were also assessed using questionnaires. Analyses included single, partition, and substitution Cox proportional hazards models, adjusting for potential confounders. Analyses were conducted in 2025.
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>Results
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>There were 569 incident cases of dementia over 393,104 person-years; median follow-up time was 19.2 years. Mentally passive sedentary behavior was associated with a higher incidence of dementia in crude (hazard ratio=1.16, 95% CI=1.11, 1.22) but not adjusted models (hazard ratio=1.04, 95% CI=0.98, 1.10). Each additional 1 hour per day of mentally active sedentary behavior was associated with a 4% lower risk for developing dementia (hazard ratio=0.96, 95% CI=0.93, 0.98). There was a significant age interaction, indicating a higher protective effect of mentally active sedentary behavior among older participants (aged 50–64 years). In the partition models accounting for all behaviors, increasing 1 hour per day of mentally active sedentary behavior, while maintaining passive sedentary behavior and light and moderate-to-vigorous physical activity constant, was associated with an 11% lower risk for incident dementia (hazard ratio=0.89, 95% CI=0.81, 0.97). Similarly, substituting 1 hour per day of passive sedentary behavior with the same amount of mentally active sedentary behavior was associated with a 7% reduction in the risk for incident dementia (hazard ratio=0.93, 95% CI=0.87, 0.99).
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>Conclusions
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>Mentally passive sedentary behavior may increase the risk of dementia. Replacing passive with mentally active sedentary behaviors or with physical activity may reduce the risk of dementia in older adults.

Once again, gaming is the best use of screens.

Is chatting with people online counted as an active behavior?