Inter-relationships between physical activity, body mass index, sedentary time, and cognitive functioning in younger and older adults: cross-sectional analysis of the Canadian Community Health Survey

Objectives: Engagement in leisure-time physical activity (LTPA) is protective against cognitive decline whereas obesity and sedentary behaviors are associated with impairments in perceived cognitive function. Currently, little is known about how these relationships vary across the lifespan. This study investigated the inter-relationships between LTPA, leisure-time sedentary time (LTST), body mass index (BMI), and perceived cognitive functioning in younger and older Canadian adults. Study design: This is a cross-sectional study. Methods: Data from the 2012 annual component of the Canadian Community Health Survey (n = 45,522; >= 30 y) were used to capture LTPA, BMI, LTST, and perceived cognitive function. The inter-relationships were assessed using both mediation analyses and general linear models. Results: Lower LTPA and higher BMI and LTST were related to poorer perceived cognitive functioning (P < 0.0001) and LTPA mediated the BMI-perceived cognitive functioning (Sobel's test: t = 3.24; P < 0.002) and LTST-perceived cognitive functioning (Sobel test: t = 3.35; P < 0.002) relationships. Conclusion: Higher LTPA levels contribute to better perceived cognitive functioning scores both independently and by way of offsetting the impact of elevated BMI and LTST on cognitive function. (C) 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.