RACIAL DIFFERENCES IN THE RELATIONSHIP OF PHYSICAL ACTIVITY TRAJECTORIES ON COGNITIVE FUNCTION TRAJECTORIES

Abstract

Prior observational studies have shown that physical activity reduces the risk of cognitive decline. Furthermore racial disparities in cognitive health have been found that older African Americans (AAs) have poor cognitive function than older White Americans. However, no studies have examined the association between trajectory patterns of physical activity and cognitive function trajectories among older Americans and whether the association differs between older AAs and Whites. This study used a group-based mixture model to identify distinct physical activity and cognitive function trajectory groups by analyzing a 16-year longitudinal data obtained from the Health and Retirement Study (1998–2014). Three distinct cognitive function trajectory groups (C1=high, C2=moderate, C3=low cognitive function) and five distinct physical activity trajectory groups (P1=active, P2=active-decreased to moderate, P3=moderate, P4=moderate-decreased to inactive, P5=inactive) were identified. Significant interaction effects between race and physical activity trajectories (i.e., P1xAAs, P2xAAs) on cognitive function trajectories were found. Stratified analyses was conducted to examine how the association differed by racial groups. Results showed that people who were active (P1) compared to inactive people were more likely to be in high cognitive function group (C1). The magnitude of the association was found to be greater in AAs (OR=6.11) than in Whites (OR=5.11). However, P2 group (active-decreased to moderate) was associated with high cognitive function (C1) only in Whites (OR=2.20). In conclusion, the trajectory patterns of physical activity were associated with cognitive function trajectories. The associations were moderated by racial groups. Future studies can further examine other behavioral risk factors trajectories and associations with cognitive function