Determining pathways of effect between correlates and outcomes of transport-related physical activity at differing timepoints across the lifecourse: A structural equation modelling approach

Transport-related physical activity levels differ across the lifecourse; however, the nature of these differences is poorly understood. This study examined the relationship between correlates of transport-related physical activity and how they differ in strength, pathway, and direction across the lifecourse. Structural Equation Modelling assessed relationships between correlates (e.g., age, smoking, education) and transport-related physical activity (assessed via the International Physical Activity Questionnaire) at four timepoints of the Australian Childhood Determinants of Adult Health study: childhood (7-15y; n = 6302), early-adulthood (26-36y; n = 2700), early/ mid-adulthood (31-41y; n = 1649), and mid-adulthood (36-49y; n = 1794). Several pathways were consistent across the lifecourse. Self-rated health directly associated with transport-related physical activity across all timepoints. During adulthood greater body mass index and smoking frequency were indirectly associated with lower levels of transport-related physical activity via self-rated health; similarly, lower educated adults, who smoked more frequently, and had poorer health, had lower transport-related physical activity. Urban residence was directly associated with greater transport-related physical activity in childhood and early-adulthood; having more children in early/mid-and mid-adulthood was directly associated with less transport-related physical activity.This is the first study to report pathways of direct and indirect association between correlates and transport related physical activity at key lifecourse stages. The pathways highlighted can inform policy and practice to aid in the development of agespecific lifecourse interventions.