Table 3.

PiB status by APOE4 and quartiles of blood amyloid-β1–42 at baseline (2000–02) and follow-up (2009) in the Pittsburgh GEMS cohort

	Quartile	APOE4−				APOE4+
		n	# PiB+	% PiB+	Age-adjusted P-value	n	# PiB+	% PiB+	Age-adjusted P-value
Amyloid-β1–42 baseline	1	27	16	59.3		11	10	90.9
	2	30	11	36.7		7	6	85.7
	3	28	14	50.0		9	8	88.9
	4	33	10	30.3	0.072	4	3	75.0	0.844
Amyloid-β1–42 follow-up	1	26	13	50.0		7	7	100.0
	2	25	16	64.0		6	5	83.3
	3	28	9	32.1		3	1	33.3
	4	23	6	26.1	0.026	7	6	85.7	0.450

Quartile cut points—amyloid-β1–42 baseline: 1Q: ≤6.36, 2Q: 6.37–9.38, 3Q: 9.39–13.86, 4Q: >13.86; amyloid-β1–42 follow-up: 1Q: ≤6.13, 2Q: 6.14–9.54, 3Q: 9.55–14.01, 4Q: >14.01. Q = quartile.