Fig. 3

Correlations between depressive symptoms in 2019 and serum cytokine concentrations in 2015. In 2019, a significant, positive correlation between the CES-D scores and serum concentrations of the cytokine TNFα was observed in men. As to the CES-D scores of men in 2019, when IL-17A concentrations were divided into higher and lower groups with a cutoff at 3.35 pg/mL, the serum IL-17A level of the higher group showed significantly increased CES-D scores in 2019 in comparison with that of the lower IL-17A group (t-test: t = 2.63, p = 0.019). IL-6, IL-10, IL-12 and IL-17 concentrations were base 10 log-transformed. CES-D: the Centre for Epidemiologic Studies Depression Scale