ACP5 and Alzheimer disease: Likewise, PTH (test statistic = 26.406, p < 0.0001), P1NP (test statistic = 26.161, p < 0.001), and TRAcP 5b (test statistic = 15.831, p = 0.001) all showed statistical difference with AD groups higher than CON groups (Fig. 2B–D).