Dementia was more prevalent among those who were non-Hispanic Black with high cystatin C (25% in this double exposed group) than those who were non-Hispanic Black with low cystatin C (8.2% in this single exposed group), non-Hispanic White with high cystatin C (5.5% in this single exposed group), or non-Hispanic White with low cystatin C (1.9% in this unexposed group; Supplementary Table 3). The gene discussed is CST3; the disease is dementia.