Prospective bi-directional associations between sedentary time and physical activity with cognitive performance: a cohort study

This prospective study determined whether: (1) objective physical activity (PA) and sedentary (SED) time at 9 years was associated with cognition at 15 years, (2) cognition at 9 years was associated with PA and SED at 15 years, and (3) the change in PA and SED from 9 to 15 years was associated with the change in cognition. Cognitive performance was assessed from picture vocabulary, verbal analogy, passage comprehension, and applied problem tasks. Regression models were used to explore each aim while adjusting for covariates. Among the combined sample, SED (min center dot day(-1)) at 9 years was unrelated with cognitive performance at 15 years, whereas participating in >= 60 min center dot day(-1) of moderate-to-vigorous PA (MVPA) at 9 years predicted lower cognitive scores at 15 years. In the reverse direction, cognitive performance at 9 years was unrelated with SED and MVPA (min center dot day(-1)) at 15 years. Over 6 years, increased SED (min center dot day(-1)) predicted lower improvement to verbal analogy scores (B = -0.01, p = 0.028). In comparison, an increase (or relatively smaller decline) in MVPA (min center dot day(-1)) predicted greater improvement in applied problem scores (B = 0.06, p = 0.007). Contextual information regarding SED and MVPA behavior would help understand bi-directional associations of activity and cognition.