The decomposition analysis comparing non-Hispanic Black to White participants, adjusting for demographic variables, showed that the mediating effect of cystatin C accounted for 2% (95% CI: −0, 4%) of the observed racial disparity in dementia (Table 5), while the portion attributable to the interaction between exposure and mediator (moderating pathway) accounted for 8% (95% CI: −5, 22%) of the disparity. The gene discussed is CST3; the disease is dementia.