Integrated development for r

A combination of software packages was used for analyses, including SPSS Statistics version 22.0 (IBM Corp., Armonk, NY), RStudio: Integrated Development for R (RStudio, Inc., Boston, MA), and SAS version 9.4 (SAS Institute Inc., Cary, NC). Two-sided significance was set at α=0.05 (type I error rate). Standard summary measures were used to describe demographic and clinical characteristics for the sample, stratified by statin exposure, with group comparisons obtained through t test for continuous variables and χ2 test for categorical variables. ANCOVA models adjusting for age and sex were used to test for associations between statin exposure and individual neuroimaging measures and to generate corresponding adjusted Cohen’s d effect sizes. Prior to statistical analysis, the amyloid and tau PET and WMH phenotypes were transformed by natural log to ensure a normal distribution. To assess the robustness of associations of the statin exposure variable with neuroimaging measures, post-hoc sensitivity analyses were performed using a one-to-one age- (within 3 years) and sex-matched subset of 522 individuals and using conditional logistic regression to account for the matching.