Not all screen time is equal, the study found.
You might know the feeling of opening up your phone on Sunday and being absolutely offended by the amount of time you’ve spent looking at your screen the week before. (16 hours? No, that can’t be right.) Screen use can cause a slew of problems for adults, from interfering with sleep to possibly increasing depression. Now, a new study has uncovered a link between screen time in older adults and dementia risk — but there’s more to the results than the obvious.
The study, published in Psychological and Cognitive Sciences, examined what researchers dubbed “leisure-time sedentary behaviors,” which included activities like going on the computer or watching TV, and their impact on dementia risk. Sedentary behaviors in general have been shown to increase risk for cardiovascular disease, stroke, certain types of cancer, and other health issues. For the study, researchers examined a total of 146,651 participants in the U.K. above age 60 who did not have a dementia diagnosis. The participants were asked about their leisure-time sedentary behaviors and separated into groups: time spent watching TV and time spent on the computer.
What did the study find?
After an average follow-up time of 11.87 years, 3,507 cases of dementia were diagnosed among the group of participants. When researchers controlled for various factors, including time spent doing physical activity, they found that sitting time primarily spent watching TV was associated with a higher risk of dementia — about 24 percent. Interestingly, the study found that spending time on the computer was associated with a lower risk of dementia, reducing risk by 15 percent.
Why is watching TV associated with higher dementia risk and computer use is not?
Even though both activities involve looking at a screen, there is an important difference between watching TV and being on the computer. Researchers explained that watching TV is cognitively passive, as much as some of us may want to believe that watching true crime documentaries all day is making us smarter, while spending time on the computer is cognitively active.
What’s interesting, too, is that these risks persisted even among participants who were more physically active. This is important to note given that a previous study found that adults who took at least 9,826 steps per day cut their risk of being diagnosed with dementia in half (and walking 3,800 steps per day could decrease risk by 25 percent).
If it seems like there have been a lot of developments about dementia recently, it’s because there have — a University of Cambridge study released last week found that a new logic and memory test could identify dementia up to nine years earlier than before, and a June 2022 study found that a decrease in walking speed could be an early sign of dementia.
