Figure 1
From: Adjustment for physical activity in studies of sedentary behaviour
Physical activity as a common cause (confounder) of sedentary behaviour and disease outcomes. a PA is a common cause of SB and the outcome (D). C is an exogenous variable that is a common cause of both PA and SB. b The causal direction between PA and SB is unknown. C is an exogenous variable that is a common cause of both PA and SB. c PA is a common cause of SB and the outcome (D), with sub-scripts denoting measurement at time 1 and time 2. C is an exogenous variable that is a common cause of both PA and SB.