correlation in the outcome values was chosen. The mixed model was fitted between each SNP and PHV Z-score without pre-defined covariance structure for the error matrix (type = unstructured), with SAS PROC MIXED (version 9.1.3.). Age was included into the model as a binary variable (0 = infancy, 1 = puberty) and the age-SNP interaction was tested. The analysis was weighted by the number of measurement points at the age window in question (on average 7–8 measurements per person at both ages). The model was additionally adjusted for sex and PCs.
