HealthDay News — For older adults, time spent watching television is associated with increased dementia risk, even after adjustment for confounding variables, including physical activity, according to a study published online Aug. 22 in the Proceedings of the National Academy of Sciences.
David A. Raichlen, Ph.D., from the University of Southern California in Los Angeles, and colleagues examined whether sedentary behavior is associated with incident dementia regardless of engagement in physical activity in a study involving 146,651 participants from the U.K. Biobank aged 60 years or older. Self-reported leisure-time sedentary behavior was divided into time spent watching television and time spent using a computer. During a mean follow-up of 11.87 years, 3,507 individuals were diagnosed with all-cause dementia.
The researchers found that time spent watching television was associated with an increased risk for incident dementia in models adjusted for a wide range of covariates, including time spent in physical activity (hazard ratio, 1.24), while time spent using a computer was associated with a reduced risk for incident dementia (hazard ratio, 0.85). Television time and computer time remained significantly associated with dementia risk at all physical activity levels.
“In this study, we show that sedentary behaviors are associated with incident dementia; however, sedentary behavior domain and context determine the direction of the associations,” the authors write.