Figure 4.

Adjusted differences in the mean 5-y rate of change in global cognition, processing speed, and episodic memory per 1-SD increment in TRAP exposure, estimated from our primary analysis ($n=\mathrm{6,061}$). Note: All models adjusted for baseline age, sex, race, study time, educational attainment, smoking status, community noise level, neighborhood socioeconomic status and cross-products between these variables and study time. The parameter of interest was the interaction between TRAP exposure and study time. Models for ${\mathrm{NO}}_{\mathrm{X}}$ and ${\mathrm{NO}}_2$ additionally adjusted for the calendar year of the baseline visit. In addition, although CHAP collected data on its participants from 1993 to 2012, model-based predicted values of ${\mathrm{NO}}_{\mathrm{X}}$ and ${\mathrm{NO}}_2$ for CHAP participants were available from 1999 to 2012, whereas model-based predicted values for ${\mathrm{PM}}_{2.5–10,\mathrm{Cu}}$ and ${\mathrm{PM}}_{2.5–10,\mathrm{Zn}}$ were available for 2009 only. To partially address this misalignment of exposure and outcome ascertainment, we used the procedure described in the main text to assign 3-y TRAP exposures to each participant in our analytic sample. We modeled associations between TRAP and rates of cognitive change, correcting for potential post-baseline attrition bias by incorporating inverse probability-of-continuation weights into our GEE models. CHAP, Chicago Health and Aging Project; GEE, generalized estimating equations; PM, particulate matter; SD, standard deviation; TRAP, traffic-related air pollution.