Table 1.

Summary of How the Analytic Groups Were Composed

	Religious Orders Study	Memory and Aging Project	Combined Studies
Total number of participants	1,160	1,482	2,642
No cognitive impairment at baseline	796	1,010	1,806
Died before first follow-up	18	22	40
Enrolled < 1 year	7	69	76
Eligible for follow-up	771	919	1,690
Follow-up ≥1 year	758	883	1,641
Follow-up ≥ 4 years	646	593	1,239
Developed Alzheimer's disease	134	92	226
Died	97	46	143
Had brain autopsy	95	42	137
Neuropathologic examination completed	88	38	126