Tuesday, August 23, 2022

Television Watching, Computer Use Found to Have Opposite Impact on Dementia Risk

A study published in PNAS has found that older adults who spend many hours a day watching television are at increased risk of developing dementia, but those who spend more than an hour daily on a computer have a slightly reduced risk of dementia. These findings remained strong regardless of how much or little the adults engaged in physical activity.

“Our results help clarify associations of [sedentary behavior] with brain health and suggest that it is not time spent sitting per se but the type or context of leisure-time [sedentary behavior] that is associated with dementia risk,” wrote David A. Raichlen, Ph.D., of the University of Southern California and colleagues.

Raichlen and colleagues used data from the UK Biobank, a database that contains both baseline and follow-up health, lifestyle, and genetic information from about half a million adults in the UK. For their analysis, Raichlen and colleagues examined data on 146,651 participants who were at least 60 years old and dementia-free at the baseline assessment. During the follow-up period (average of 12 years), 3,507 of these adults developed dementia.

The researchers found that adults who spent 4 hours a day or more watching TV had about 20% greater risk of developing dementia than those who spent less than 2 hours a day watching TV. In contrast, adults who spent 1 hour or more on a computer daily had a 24% reduced risk of dementia compared with those who spent less than 30 minutes on a computer. The amount of physical activity in which subjects engaged did not significantly impact these estimated risks.

“While [physical activity] is associated with a beneficial reduction in dementia risk, this relationship does not strongly impact associations between leisure-time [sedentary behaviors] and dementia risk, suggesting two key and potentially separate behavioral pathways for altering risk of incident dementia,” Raichlen and colleagues wrote.

“[O]ur results highlight a key behavioral characteristic for public health messaging and modification,” the authors concluded. “Reducing cognitively passive [sedentary behaviors] like TV watching and increasing cognitively active [sedentary behaviors] like computer use, by even a small amount, may have an important impact on dementia risk in individuals regardless of their engagement in [physical activity].”

To read more on this topic, see the Psychiatric News AlertStudy Pinpoints Activities Associated With Reduced Risk of Cognitive Decline.”

(Image: iStock/Charday Penn)

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