25(OH)D levels and their relationship to C4 and C3. Comparison of concentrations of complement components C4 and C3 in 4 different 25(OH)D serum level groups and analysis of statistical significance. A and C: Set of data points with linear regression line. B and D: Box-and-Whisker plot illustrating trend and statistical significance with variability outside the upper and lower quartiles.
Sakem et al. BMC Medicine 2013 11:176 doi:10.1186/1741-7015-11-176