Fig. 1

A–C Scatterplots of serum selenium levels at baseline and biological age estimators. The x-axis is log-scaled. All available participants of the older age group are included. D–F Boxplots of biological age estimators stratified by selenium status (deficient vs. sufficient. cut-off 90 μg/L) at baseline. Statistical significance of difference between group means was assessed by t-test. Note: DNAmAA = DNA methylation age acceleration; biolog. = biological years; chron. = chronological years. Boxplots show the median, hinges (corresponding to 25 th and 75 th percentile) and whiskers (1.5*inter-quartile range (IQR))