Fig. 1

Cerebrospinal fluid (CSF) levels of tau and amyloid markers in older African Americans and Caucasians according to cognitive function. Composite cognitive Z-scores are shown on the x-axis (lower score corresponds to worse cognitive function). African Americans (closed circles) had lower CSF levels of total tau (t-tau) (a), tau phosphorylated at threonine 181 (p-tau₁₈₁) (b), and β-amyloid 1–40 (Aβ40) (d) than Caucasians (open circles). Raw values are shown, with dashed lines representing trends among Caucasians and solid lines representing trends among African Americans. The differences persisted after adjusting for age, sex, apolipoprotein E (APOE) and ABCA7 genotypes, and β-amyloid 1–42 (Aβ42) levels (c), which did not differ between the two groups. CSF biomarker t-tau/Aβ42 ratio was lower in African Americans than in Caucasians when there was cognitive impairment (e), but race did not have a significant effect on CSF biomarker Aβ42/Aβ40 (f)