Figure 3.

Trajectories of body mass index (weight (kg)/height (m)²) (A), alternate Mediterranean diet (A-MeDi) score (B), and total (C) and low-intensity (D) physical activity during the 23, 15, and 13 years preceding ascertainment of cognitive decline among cases of cognitive decline (n = 1,496) and controls (n = 7,478) in the Nurses’ Health Study, United States, 1976–2000. Mean predicted trajectories (solid lines, cases; dashed lines, controls) with 95% pointwise confidence intervals (shading) were predicted using a latent process linear mixed model according to the number of years preceding ascertainment of cognitive decline. The model included a quadratic function of time (time, time²) and adjusted for case-control status, age, and educational level and their interactions with the function of time; correlated random effects were considered on both the intercept and the time function. Trajectories were plotted for the most common profile of covariates in the study sample (a registered nurse aged 51 years in 1976). Outcomes were normalized by means of I-splines, and the corrected thresholds for multiple testing were α = 0.03 for body mass index, α = 0.02 for A-MeDi score, α = 0.02 for low-intensity physical activity, and α = 0.01 for total physical activity. MET, metabolic equivalent of task.