Table 1.

Sample Characteristics Across the Four Studies

	Study
	GENDER		OCTO-TWIN		OCTO		NONA
Start year	1995		1990		1987		1999
Years of follow-up	4		8		6		4
Occasions	2		5		4		3
N at T1	112		335		228		104
	M (SD)	n (%)	M (SD)	n (%)	M (SD)	n (%)	M (SD)	n (%)
Depressive symptoms T1	52.16 (9.36)		48.75 (9.97)		55.28 (10.54)		50.73 (10.07)
Time-to-disability T1	−3.61 (2.94)		−1.90 (2.31)		−0.40 (1.04)		−0.93 (1.26)
Age T1	75.20 (2.61)		83.83 (3.29)		86.95 (2.28)		89.51 (3.24)
Years of education	7.41 (2.17)		7.16 (2.42)		6.49 (1.79)		6.79 (1.89)
Women		60 (54)		221 (66)		147 (64)		73 (70)
Widowed		31 (28)		181 (54)		136 (60)		71 (68)
Institutionalized (predisability)		15 (13)		115 (34)		84 (37)		49 (47)
Institutionalized (disability onset)		14 (13)		114 (34)		84 (37)		49 (47)
Institutionalized (postdisability)		28 (25)		188 (56)		126 (55)		68 (65)
Memory (predisability)	51.54 (13.62)		41.12 (17.46)		40.15 (16.20)		42.50 (15.05)
Memory (disability onset)	35.55 (26.20)		35.67 (20.40)		39.24 (16.77)		38.51 (18.21)
Memory (postdisability)	35.55 (26.12)		39.41 (18.90)		41.24 (15.58)		40.67 (16.85)
Multimorbidity (predisability)	2.15 (1.35)		1.75 (1.41)		0.39 (0.64)		1.18 (1.13)
Multimorbidity (disability onset)	2.15 (1.35)		1.74 (1.41)		0.39 (0.64)		1.11 (1.11)
Multimorbidity (postdisability)	2.35 (1.43)		2.18 (1.55)		0.57 (0.74)		1.11 (1.11)
Social support (predisability)	50.39 (11.20)		45.97 (12.42)		44.17 (11.23)		47.57 (10.41)
Social support (disability onset)	46.99 (16.30)		44.49 (13.47)		43.65 (11.63)		42.68 (17.55)
Social support (postdisability)	46.89 (16.13)		45.65 (10.23)		42.89 (9.67)		42.98 (16.36)

Note: Scores for depressive symptoms standardized to a T metric (M = 50; SD = 10) using the pooled sample of all participants at baseline assessment T1 as the reference (N = 1,440).