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. Author manuscript; available in PMC: 2009 Sep 14.
Published in final edited form as: J Natl Cancer Inst. 1998 Jan 7;90(1):30–36. doi: 10.1093/jnci/90.1.30

Tabic 3.

Results of regression analyses for predicting the blastogenic response to concanavalin A (Con A) and phytohemagglutinin A (PHA) across three concentrations each

Dependent variable: blastogenic response of mitogen
Con A
 PHA
10
μg/mL		 5
μg/mL		 2.5
μg/mL		 10
μg/mL		 5
μg/mL		 2.5
μg/mL
Model A, R2A* .035 .043 .054 .022 .024 .033
Model AA, R2AA† .105 .125 .115 .023 .024 .033
Model B‡
     R2B .166 .174 .147 .083 .074 .080
     R2B–AA§ .061 .049 .032 .060 .050 .047
     βStress∥ −.255 −.229 −.187 −.256 −.234 −.229
     t(df = 103) −2.668 −2.401 −1.927 −2.521 −2.299 −2.254
     P .010 .018 .058 .014 .024 .026
Model C#
     R2C .053 .065 .053 .070 .054 .052
     t(df = 108) −2.443 −2.724 −2.443 −2.857 −2.489 −2.441
     P .016 .008 .016 .006 .014 .016
*

Model A includes the control predictors of age, stage, and days since surgery for the immune outcome, blastogenesis. The R2A is the totla variance in blastogenesis explained by these three predictors.

†

Model AA includes model A variables plus the control predictor of number of T cells for the immune outcome, blastogenesis. The R2AA is the total variance in blastogenesis explained by these four predictors.

‡

Model B includes model AA control variables plus the stress predictor (i.e., Impact of Event Scale [IES] score) for the immune outcome, blastogenesis. The R2B is the total variance in blastogenesis explained by the four control predictors and the stress predictor.

§

R2B–AA is the increment in variance due to stress only (i.e., variance beyond that explained by the control predictors) in predicting the blastogenesis outcome.

∥

βStress is the standardized regression beta (β) for the stress variable in model B. It indicates the magnitude and direction of the influence (negative) of stress on the immune outcome.

df refers to the degrees of freedom in model B.

#

Model C includes stress as the only predictor of the immune outcome, blastogenesis. The R2C is the total variance in blastogenesis explained by stress; this model provides the simple association between psychologic stress and immune function.