CHI3L1 and hypertensive disorder: In subsequent stratified analyses, we found that higher CSF levels of YKL-40 were associated with higher levels of p-tau in the HTN + subgroup (β = 0.708, p < 0.001) rather than in the HTN- subgroup (β = 0.284, p = 0.066) (Figure 3A and Supplementary Table 4 in Supplementary Material 1).