PON1 and rheumatoid arthritis: Multiple comparisons by ANOVA showed significantly lower plasma PSH concentrations and PON-1 activity in RA patients compared to controls (3.15 ± 3.7 vs. 3.77 ± 0.7 μmol/gr protein, p < 0.001, and 109.73 ± 67.4 vs. 128.09 ± 76.2 U/L, p = 0.042, respectively) (Table 3).