Figure 2.

Predicted cognitive declines over time for varying levels of continuous forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC), Atherosclerosis Risk in Communities (ARIC) Study, 1990–2019. Data were obtained from a linear mixed model with prediction computed at years 0, 6, 10, 15, 20, 25, and 30 (the model incorporated linear splines with a knot at the sixth year from ARIC visit 2). Plausible values of FEV₁ and FVC were chosen. The gray, orange, blue, green, and purple lines represent the cognition trajectories for the groups “both low” (FEV₁ = 1.5 L, FVC = 2.5 L), “both medium” (FEV₁ = 2.5 L, FVC = 3.5 L), “both high” (FEV₁ = 3.5 L, FVC = 4.5 L), “equal” (FEV₁ = 3.5 L, FVC = 3.5 L), and “FVC − FEV₁ > 2” (FEV₁ = 1.5 L, FVC = 4.0 L), respectively. The 30-year decline was steepest among persons with the highest difference between FVC and FEV₁.