Leisure-time sedentary behaviors are differentially associated with all-cause dementia regardless of engagement in physical activity
David A. Raichlen, Yann C. Klimentidis, M. Katherine Sayre, Pradyumna K. Bharadwaj, Mark H. C. Lai, Rand R. Wilcox, and Gene E. Alexander
Georgia Institute of Technology, Atlanta, GA
August 22, 2022
119 (35) e2206931119
Sedentary behaviors (SBs), like watching television (TV) or using a computer, take up a large portion of adult leisure time and are linked to increased risk of chronic disease and mortality. We investigate whether SBs are associated with all-cause dementia regardless of physical activity (PA). In this prospective cohort study using data from the UK Biobank, high levels of cognitively passive SB (TV) were associated with increased risk of dementia, while high levels of cognitively active SB (computer) were associated with reduced risk of dementia. These relationships remained strong regardless of PA levels. Reducing cognitively passive TV watching and increasing more cognitively active SBs are promising targets for reducing risk of neurodegenerative disease regardless of levels of PA engagement.
Sedentary behavior (SB) is associated with cardiometabolic disease and mortality, but its association with dementia is currently unclear. This study investigates whether SB is associated with incident dementia regardless of engagement in physical activity (PA). A total of 146,651 participants from the UK Biobank who were 60 years or older and did not have a diagnosis of dementia (mean [SD] age: 64.59 [2.84] years) were included. Self-reported leisure-time SBs were divided into two domains: time spent watching television (TV) or time spent using a computer. A total of 3,507 individuals were diagnosed with all-cause of dementia over a mean follow-up of 11.87 (±1.17) years. In models adjusted for a wide range of covariates, including time spent in PA, time spent watching TV was associated with increased risk of incident dementia (HR [95% CI] = 1.24 [1.15 to 1.32]) and time spent using a computer was associated with decreased risk of incident dementia (HR [95% CI] = 0.85 [0.81 to 0.90]). In joint associations with PA, TV time and computer time remained significantly associated with dementia risk at all PA levels. Reducing time spent in cognitively passive SB (i.e., TV time) and increasing time spent in cognitively active SB (i.e., computer time) may be effective behavioral modification targets for reducing risk of dementia for the brain regardless of engagement in PA.