2.6. Statistics
Statistical analysis was performed in collaboration with a medical statistician who provided the code for the fitting of a linear mixed effects model in Rstudio (Rstudio, Package lme4). As fixed effects, we included the treatment order (six possible orders), period (first, middle, last), treatment (FAE, AE, placebo), and time (pre, post), along with the interaction between treatment and time. As random effects, we included record id and record id within period. Standard normality tests of residuals were conducted, including quantile-quantile plots and histograms, along with plots of residuals versus fitted values. We used the Rstudio package emmeans to compute estimated marginal means from the mixed model. We will simply refer to the estimated marginal means as ‘means’ throughout this article. We also compared mean differences (Δ-mean) between the three supplementations and obtained the corresponding If values were below the lower level of detection in the previously described assays, we imputed these values as half of the lower limit of detection for the respective assays. We assessed the baseline data for normality, and for normally distributed data, we will report the results as mean ± standard deviation (SD). Non-normally distributed data will be reported as the median along with the interquartile range (IQR).