On the diagonal, the marginal distributions are shown as histograms. In the lower left triangle of the figure, we indicate the respective correlation coefficients, confidence intervals, and p-values. P-values less than 0.05 are shown in bold face. For clarity, and since correlations are scale independent, we omitted the axis labels. Urinary hepcidin, intensity/mMol creatinine, is abbreviated Hep; ferritin, µg/L, is abbreviated ferr.