Abbreviations: APOE4: apolipoprotein E4; IGF-1: insulin-like growth factor-1; VEGF: vascular endothelial growth factor; BDNF: brain-derived neurotrophic factors; SE: standard error; DM: diabetes mellitus. Model 1: adjusted for age and sex; Model 2: additionally adjusted for body mass index, smoking, total cholesterol, triglycerides, lipid medication, and APOE4. of stairs and city blocks walked each day, which were added together to quantify the total amount of ambulatory (walking) physical activity. Ambulatory activity was natural log transformed, sedentary time was square root transformed, and total physical activity (PAI) was inverse transformed, but we reversed the sign for total physical activity to make higher values consistent with more physical activity. VEGF was also natural log transformed. All variables were standardized to a mean of 0 and SD of 1 to facilitate comparison. Significant values () were set in bold for emphasis.