Fig. 2
Association between physiological stress load and Treg frequencies. (A) Frequency of Tregs grouped by subject age. Statistical analysis was performed using Kruskal-Wallis non-parametric one-way ANOVA; ***P < 0.001. Linear regression of Treg frequencies and (B) physiological stress load, (C) serum DHEA-S, and (D) urinary norepinephrine for young (18–33 y), middle (34–49 y), and old (50–66 y) subjects. Correlation squared (R2) and P values for each association constant are shown for the linear regression