Figure 2 A.

Box plots for global cognitive z-scores presented according to time since enrollment and exposure status at the time of Mayo Clinic Study of Aging (MCSA) visit. Time since enrollment was grouped into intervals based on planned time between MCSA visits (first z-score at enrollment, 8–22, 23–37, 38–52, and 53–67 months). A z-score measures how far a score is (in standard deviations) from the mean.