Table 1. Study characteristics of participants.

Prospective analysis: incident dementia and AD (baseline characteristics)
	FHS	AGES	SALSA	ARIC	RS	IDCD
Year of inception	Offspring cohort exam 7 (1998–2001)	AGES II (2007–2011)	1998	Visit 4 (1996–1998)	2004–2008	N/A
N	301	623	586	1,197	608	N/A
Mean age (years)	70.1 ± 5.9	76.4±5.3	69.9±6.6	64.0±5.8	63.6±7.8	N/A
N (%) women	123 (44.4)	285 (45.8%)	313 (56.4)	646(54.0)	274 (45.1)	N/A
Duration of follow-up (years)	7.5±4.8	5.2±0.2	5.3±3.1	12.3±4.4	6.4±2.5	N/A
Incident dementia, N (%)	38 (13.7)	27 (8.1)	55 (9.4)	198 (11.24)	31 (5.1)	N/A
Incident AD, N (%) among diabetics	30 (10.8)	20 (6)	32 (5.5)	N/A	16 (2.7)	N/A
Cross-sectional analysis: cognition
	FHS	AGES	SALSA	ARIC	RS	IDCD
Visit (years)	Offspring cohort exam 8 (2005–2008)	AGES I (2002–2006)	1998–1999	visit 5 (2011–2013)	2004–2008	2010–2012
N	322	694	586	1,732	451	912
Mean age (years)	70±9	77±6	70±7	76±5	63±8	73±5
N (%) women	127 (39.4)	3,166 (57)	332 (56.7)	981 (57)	199 (44)	539 (59)
Longitudinal analysis: cognition (baseline characteristics; including prevalent dementia cases)
	FHS	AGES	SALSA	ARIC	RS	IDCD
Baseline visit (years)	Offspring cohort exam 7 (1998–2001)	AGES I (2002–2006)	1998–1999	Visit 4 (1996–1998)	2004–2008	N/A
N	194	287	586	1,197	250	N/A
Mean age (years)	64±9	75±4	70±7	64±6	61±7	N/A
N (%) women	80 (41)	134 (46.7)	332 (56.7)	646 (54.0)	103 (41.2)	N/A
Cross-sectional analysis: brain MRI measures
	FHS	AGES	SALSA	ARIC	RS	IDCD
Visit (years)	Offspring cohort exam 8 (2005–2008)	AGES I (2002–2006)	1998–1999, 2002	visit 5 (2011–2013)	2004–2008	2010–2012
N	234	N/A	85	575	349	125
Mean age (years)	69±8	N/A	71±7	76±5	61±8	72±4
N (%) women	86 (36.8)	N/A	46 (54.1)	340 (59)	144 (41.3)	48 (38)