Plasma amyloid beta measurements - a desired but elusive Alzheimer's disease biomarker

Table 2 Longitudinal studies in populations including Down syndrome

Study	Subjects	Mean age (years)	Follow-up duration	Platform and antibodies	CV	Analyte associated with conversion risk	Magnitude
Schupf et al. 2007 [32]	44 DSp	-	5 years^a	ELISA	-	baseline Aβ_1-42	HR = 2.6
	130 cnDS			6E10
				R182
				R165
Schupf et al. 2010 [33]	61 DSp	53.7	-	ELISA	-	Decrease of Aβ_1-40	HR = 0.4
	164 cnDS	50.3		6E10		Stable Aβ_1-42	HR = 2.6
				R182		Decrease Aβ_1-42	HR = 4.9
				R165		Stable Aβ_1-42/Aβ_1-40	HR = 3.9
						Decrease Aβ_1-42/Aβ_1-40	HR = 4.9
Coppus et al. 2012 [54]	79 DSp	53.3	-	xMAP		↑ baseline Aβ_1-40	HR = 2.05
	264 cnDS	50.6		INNO-BIA		↑ baseline Aβ_1-42	HR = 2.56

^aEstimated by author of review. cnDS, cognitively normal Down syndrome; CV, coefficient of variation; DSp, Down syndrome subjects who progress to a dementia diagnosis; HR, hazard ratio.

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