July 8, 2015.
Note: My summary is based on ISR plots generated from an older set of models. I have since uploaded a larger set of models and will update my summary when the new ISR plots become available.
After adjusting for baseline age, higher initial levels of FEV1 were associated with better performance in the domains of global cognition (MMSE), verbal learning (world list immediate recall) and verbal memory (world list delayed recall), and marginally better performance in verbal fluency (categories). Change in FEV1 over time was positively associated with change in verbal memory. Negative residual correlations suggest that greater deviation from the overall cognitive trajectory was linked to less deviation from the overall trajectories of MMSE and verbal memory, and vice versa.
When education was added as a covariate, initial levels of FEV1 were no longer associated with initial levels of verbal memory. However, higher baseline FEV1 was linked to better baseline performance in visuoconstructional skills (Figure Copy). Changes in FEV1 were marginally and positively associated with changes in verbal learning. Greater deviation from the overall FEV1 trajectory was related to greater deviation from the trajectories of verbal learning and visuoconstructional skills.
In models that adjusted for baseline age, higher initial levels of FVC were associated with better performance in the domains of global cognition, verbal learning and memory, and visuoconstructional skills. Increase in FVC over time was linked to increase in verbal learning performance and visuoconstructional skills over time, although the latter association was marginally significant. Individuals who deviated more from the group’s FVC trajectory also tended to have greater deviation from the group’s trajectory on visuoconstructional skills. The pattern of findings remained the same when education was added as a covariate.