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

- Cognitive decline is a complex process; this study explored a variety of behaviors in adults 30-80 years of age.
- Lower levels of physical activity, higher body mass indices and sedentary times contribute to poorer cognitive function.
- Physical activity mediates the relationships between BMI and cognitive function and sedentary time and cognitive function.

ObjectivesEngagement 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 designThis is a cross-sectional study.MethodsData 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.ResultsLower 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.ConclusionHigher 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.