Table 2.

Relationship of Perceived Stress With Total Brain Volume^a: The Chicago Health and Aging Project

Results of linear regression models with perceived stress modeled continuously.
	Model 1 (N=571)					Model 2 (N=559)					Model 3 (N=557)
	Regression coefficient	S.E.	t[563]	P-value	Adjusted R2	Regression coefficient	S.E.	t[544]	P-value	Adjusted R2	Regression coefficient	S.E.	t[540]	P-value	Adjusted R2
Perceived Stress	−0.111	0.049	−2.28	0.023	0.317	−0.105	0.049	−2.14	0.032	0.329	−0.134	0.05	−2.69	0.0074	0.354
Results of linear regression models with perceived stress modeled categorically
	Model 1 (N=571)					Model 2 (N=559)					Model 3 (N=557)
	Regression coefficient	S.E.	t[562]	P-value	Adjusted R2	Regression coefficient	S.E.	t[543]	P-value	Adjusted R2	Regression coefficient	S.E.	t[539]	P-value	Adjusted R2
Low Stress	---	---	---	---	---	---	---	---	---	---	---	---	---	---	---
Mod. Stress	−0.449	0.392	−1.15	0.252		−0.438	0.389	−1.13	0.261		−0.532	0.383	−1.39	0.165
High Stress	−0.965	0.429	−2.25	0.025	0.316	−0.920	0.427	−2.15	0.032	0.328	−1.178	0.432	−2.73	0.0066	0.353

Note.

^aTotal brain volume calculated as total parenchymal volume/total cranial volume. Values shown are from regression models adjusted for covariates, as follows: Model 1 included age, sex, race, education, time between stress assessment and MRI. Model 2 included Model 1 covariates and vascular risk factors (risk factors included history of smoking, heart disease, stroke, diabetes, and history of hypertension). Model 3 included Model 2 covariates and depressive symptoms and diagnosis of dementia. S.E. = standard error; in each model shown, df were calculated as N – number of parameters in the model.