Older adults who spend excessive amounts of time engaging in sedentary behaviors like sitting while watching TV or driving are at an increased risk of developing dementia, according to a new study conducted by researchers from the University of Southern California (USC) and the University of Arizona. The study, published in JAMA, revealed that spending over 10 hours a day being sedentary significantly raises the risk of dementia, irrespective of whether the sedentary behavior is accumulated in long periods or spread out throughout the day.
The researchers analyzed data from the U.K. Biobank, a database of participants in the United Kingdom, focusing on a sample of over 50,000 adults aged 60 and older who did not have a dementia diagnosis at the start of the study. Participants wore wrist-worn accelerometers for 24 hours a day for one week to measure their movement. The data, combined with advanced computing techniques, provided an objective measure of their sedentary behavior.
After approximately six years of follow-up, the researchers used hospital records and death registry data to determine dementia diagnoses. The study identified 414 cases positive for dementia. The statistical analysis accounted for various factors such as demographics, lifestyle characteristics, and chronic conditions that could impact brain health.
The findings showed that the risk of dementia begins to increase rapidly after spending 10 hours a day being sedentary, regardless of how the sedentary time is accumulated. Notably, the study also revealed that lower levels of sedentary behavior, up to around 10 hours per day, were not associated with an increased risk of dementia. This suggests that while prolonged sedentary behavior is a risk factor, limiting the total daily time spent being sedentary could help mitigate the risk.
The researchers mentioned that further research is needed to establish causality and understand whether increased physical activity can reduce the risk of developing dementia. However, this study highlights the importance of addressing sedentary behavior in older adults to protect brain health and potentially prevent dementia.
It is worth noting that this study builds upon previous research conducted by the same team, which investigated the impact of different sedentary behaviors on dementia risk using self-reported health data. By utilizing wearable accelerometers in this study, the researchers were able to obtain objective measurements of sedentary behavior, providing complementary insights into its association with dementia risk.
The implications of these findings are significant, considering that the average American spends around 9.5 hours per day being sedentary. Encouraging individuals, especially older adults, to reduce sedentary time and incorporate regular physical activity into their daily routines could have long-term benefits for brain health and reduce the risk of dementia.
