Domains of Sedentary Behavior and Cognitive Function: The Health, Aging, and Body Composition Study, 1999/2000 to 2006/2007

Background: This study examines the relationship between various domains of sedentary behavior and subsequent cognitive function to evaluate whether different sedentary activities have specific associations with future cognitive performance. Methods: Data were from 1 261 older adults participating in the Health, Aging, and Body Composition (Health ABC) Study between 1999/2000 and 2006/2007. Total sitting time (hours/day), reading time (hours/week), and TV time (<= 27/>= 28 h/wk) were self-reported at baseline and 3 years later. At follow-up, cognitive function was evaluated using the Teng Mini-Mental State Examination (3MS) and the Digit Symbol Substitution Test (DSST). Multivariable linear regression modeling examined the independent associations of baseline sedentary behaviors and 3-year change in those behaviors with cognitive function scores at follow-up, adjusting for important covariables. Results: Baseline total sitting time was positively associated with 3MS (beta = 0.14 +/- 0.07; p <.05) and DSST (beta = 0.20 +/- 0.10; p <.05) scores at follow-up, as was reading time (beta = 0.09 +/- 0.03; p <.05 for 3MS score and beta = 0.14 +/- 0.04; p < 0.01 for DSST score). Participants who increased their TV watching time over 3 years had a significantly lower 3MS score (beta = -1.45 +/- 0.71; p <.05) at follow-up, compared with those who maintained a low level of TV time (referent). These findings were independent of age, sex, race, education level, health status, depressive symptoms, and physical activity. Conclusion: Some types of sedentary behavior may have benefits for cognitive function in older age, thus highlighting the importance of measuring different domains of sitting time.