AD peaks and stabilizes. In addition, prevalence for AD was very low for ages younger than 18 and the sample sizes were too small for ages older than 30. These resulted in an analytic sample of 6,884 assessments from 2,556 participants (51.6% female) with each individual having up to 6 assessments throughout the included age range. Of the whole analytic sample, 26.8% completed one assessment, 23.0% completed 2 assessments, 20.4% completed 3 assessments, and 29.8% completed 4 or more assessments. The resulting sample consisted of 0.59% of Native Americans, 0.2% of Asians, 0.35% of Pacific Islanders, 26.81% of African Americans, 66.34% of European Americans, and 5.71% of unknown self-identified racial identity.
