Table 4.

Growth Model for Depressive Symptoms Over Time-To/From-Disability: The Effect of Covariates

	Depressive symptoms
Parameter	Estimate	SE
Fixed effects
Intercepta, γ00	51.81* (0.35)
Time-to/from disability (TtfD)b, γ10	−0.22 (0.18)
Predisability, γ20	−1.03 (0.79)
Predisability × TtfDb, γ30	0.49 (0.37)
Aged 70–79, γ01	3.61 (2.59)
Aged 90+, γ02	1.09 (1.00)
GENDER study γ03	−1.98 (2.89)
OCTO-TWIN study γ04	−8.81* (0.88)
NONA study γ05	−4.67* (1.19)
Women γ06	1.56* (0.73)
Education, γ07	0.06 (0.16)
Widowhood, γ08	0.51 (0.72)
Institutionalization, γ09	1.04 (0.70)
Memory, γ010	0.04 (0.04)
Multimorbidity, γ011	0.77* (0.27)
Social support, γ012	−0.40* (0.03)
TtfD × Aged 70–79, γ11	−0.57 (1.00)
TtfD × Aged 90+, γ12	−0.04 (0.53)
TtfD × GENDER study γ13	−0.08 (1.17)
TtfD × OCTO-Twin study γ14	−0.78 (0.42)
TtfD × NONA study γ15	−0.75 (0.72)
TtfD × Women γ16	−0.07 (0.35)
TtfD × Education, γ17	0.05 (0.07)
TtfD × Widowhood, γ18	−0.42 (0.32)
TtfD × Institutionalization, γ19	0.15 (0.24)
TtfD × Memory, γ110	0.01 (0.01)
TtfD × Multimorbidity, γ111	0.07 (0.10)
TtfD × Social Support, γ112	−0.06* (0.01)
Predisability × TtfD × Aged 70–79, γ31	2.53 (1.47)
Predisability × TtfD × Aged 90+, γ32	0.76 (0.97)
Predisability × TtfD × GENDER study γ33	−1.76 (1.70)
Predisability × TtfD × OCTO-Twin study γ34	−0.31 (0.72)
Predisability × TtfD × NONA study γ35	0.45 (1.12)
Predisability × TtfD × Women γ36	0.33 (0.48)
Predisability × TtfD × Education, γ37	−0.10 (0.10)
Predisability × TtfD × Widowhood, γ38	0.03 (0.45)
Predisability × TtfD × Institutionalization, γ39	0.09 (0.34)
Predisability × TtfD × Memory, γ310	0.02 (0.02)
Predisability × TtfD × Multimorbidity, γ311	−0.06 (0.13)
Predisability × TtfD × Social Support, γ312	0.02 (0.02)
Random effects
(Residual) variance intercept, ${\text{σ}}_{u\text{0}}^{\text{2}}$	43.48* (5.54)
(Residual) variance TtfD, ${\text{σ}}_{u\text{1}}^{\text{2}}$	1.32* (0.52)
(Residual) variance predisability × TtfD, ${\text{σ}}_{u\text{3}}^{\text{2}}$	3.14** (2.01)
Covariance, σu0u1	−1.97 (1.39)
Covariance, σu0u3	4.49* (2.17)
Covariance, σu1u3	−1.97 (1.08)
Residual, ${\text{σ}}_{e\text{1}}^{\text{2}}$	38.15* (3.92)
Residual, ${\text{σ}}_{e\text{1}}^{\text{2}}$	49.66* (4.18)
Residual, ${\text{σ}}_{e\text{3}}^{\text{2}}$	44.83* (5.15)
Residual, ${\text{σ}}_{e\text{4}}^{\text{2}}$	44.88* (7.50)
Residual, ${\text{σ}}_{e5}^2$	86.11* (18.49)
−2LL	13,067
AIC	13,169

Notes: Participants in the OCTO study served as the reference category. Unstandardized estimates and standard errors are presented. N = 779 who provided 1,848 observations. Scores for depressive symptoms standardized to a T metric (M = 50, SD = 10) using the pooled sample of all oldest old participants at baseline assessment T1 as the reference (N = 1,440). AIC = Akaike Information Criterion; −2LL = −2 log likelihood, relative model fit statistics. The change in Pseudo R2 was obtained from comparing the residual within-person variance from the conditional model, including the time-to/from-disability as the time variable with that obtained from an unconditional or intercept-only model (see Snijders & Bosker, 1999, pp. 99–105).

^aIntercept is centered at disability onset.

^bSlope or rate of change is scaled in T-units per year.

*p < .05; **p = .06.