Table 3.

Linear regression of bilateral hippocampal volume on activity diversitv and covariates

	Step 1					Step 2					Step 3					Step 4
Coefficient	b	95% CI	t	p	rpartial	b	95% CI	t	p	rpartial	b	95% CI	t	p	rpartial	b	95% CI	t	p	rpartial
intercept	3649.24	2903.33, 4395.15	9.83	< .01		1343.93	335.14, 2352.72	2.68	0.01		2039.32	596.35, 3482.29	2.85	0.01		1872.43	653.78, 3091.09	3.10	<.01
activity diversity	1324.37	104.01, 2544.74	2.18	0.03	0.30	1256.94	299.84, 2214.04	2.64	0.01	0.36	1362.75	223.88, 2501.62	2.41	0.02	0.35	1217.48	263.89, 2171.07	2.58	0.01	0.37
total activity time	−28.00	−63.92, 7.92	−1.57	0.12	−0.22	−36.80	−65.13, −8.46	−2.61	0.01	−0.35	−50.10	−88.36, −11.83	−2.64	0.01	−0.37	−50.54	−79.35, −21.74	−3.54	<.01	−0.48
estimated intracranial volume						0.002	0.001, 0.002	5.64	< .01	0.63	0.001	0.00, 0.002	3.13	< .01	0.43	0.001	0.00, 0.002	3.05	<.01	0.43
age (mean centered at 46.58)											−11.64	−24.08, 0.80	−1.89	0.07	−0.28	−10.15	−20.47, 0.18	−1.98	0.05	−0.29
gender (female = ref)											159.80	−84.36, 403.95	1.32	0.19	0.20	205.90	−27.65, 439.44	1.78	0.08	0.27
education (greater than HS = ref)											37.01	−254.79, 328.81	0.26	0.80	0.04	0.72	−242.21, 243.65	0.01	1.00	0.00
race (white = ref)											17.71	−547.77, 583.19	0.06	0.95	0.01	10.33	−326.13, 346.78	0.06	0.95	0.01
time lag											−48.59	−150.67, 53.48	−0.96	0.34	−0.15	−55.94	−142.02, 30.15	−1.31	0.20	−0.20
self-rated physical health																91.47	−12.74, 195.68	1.77	0.08	0.26
model fit	F(2,49) = 2.45, p = 0.097, R2 = 0.09					F(3,48) = 13.26, p < 0.001, R2 = 0.45					F(8,43) = 6.28, p < 0.001, R2 = 0.54					F(9,42) = 6.20, p < 0.001, R2 = 0.57
change statistics						Fchange = 31.80, p < .001					Fchange = 1.59, p = .183					Fchange = 3.14, p = .08

Note. N = 52; Hippocampal volume measured in mm^3. Confidence intervals and p values for all regressors in step 3 obtained using heteroscedasticity consistent estimators; HS = high school; time lag = difíerence in months between the neuroscience and diary sub-projects.