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. Author manuscript; available in PMC: 2009 Dec 1.
Published in final edited form as: Hypertension. 2008 Nov 3;52(6):1113–1119. doi: 10.1161/HYPERTENSIONAHA.108.120196

Table 2.

Multiple regression results for base model and for additions to the model of brain aging indices and rCBF response to working memory in the thalamic ROI. Greater SBP treatment response is scored as a more negative difference from initial SBP. The r2 values associated with models define the proportion of variance explained by that model; those in the increment column define the change in the proportion of variance explained added by the variable(s) tabled.

Factor Base Model
(Step 1)		 N=43 (r2 =.39)
Beta Weight
(Standardized)		 Standard Error of Beta t-value Probability r2 increment
Age .240 .131 1.84 .07
Drug Group .068 .123 .24 Ns
Initial SBP −.660 .130 −5.09 <.001
Base Model
plus FLAIR_Aging
(Step 2a)		 N=43 (r2 =.50)
FLAIR_Aging .428 .143 3.00 .005 .11
Base Model
plus PET rCBF
ROI response
(Step 2b)		 N=37 (r2 =.49)
Thalamic ROI −.303 .128 −2.36 .02 .09
Base Model
plus
FLAIR_Aging
and Thalamic
ROI (Step 2c)		 N=37 (r2 =.60)
FLAIR_Aging .396 .137 2.90 .007
Thalamic ROI −.276 .116 −2.38 .02 .20

Note. Base model beta weights and contributions to variance shift slightly as different variables are added. These minor changes are not presented for economy of presentation. All r2 increments shown are statistically significant, p<.05. The Parietal ROI was also added as a separate step 2 variable, but was not significant (t=−.92).