. Author manuscript; available in PMC: 2015 Feb 1.

Published in final edited form as: Behav Brain Res. 2013 Nov 21;259:302–312. doi: 10.1016/j.bbr.2013.11.023

Table 2.

Regression models of Subsequent Memory Test (SMT) Accuracy

Relationship between hormone levels and subsequent recognition memory
Predictor	Unadjusted		Adjusted
Predictor	β^a	R²^b	β^a	β^c_{assay round}		R²^b

BDNF	−0.215^* (0.109)	0.059 (0.045)	−0.200 (0.107)	−0.188 (0.106)		0.103 (0.034)
Cortisol	−0.145 (0.111)	0.026 (0.009)	−0.166 (0.107)	−0.243^* (0.107)		0.100 (0.001)
IGF-1	0.063 (0.113)	0.005 (−0.011)	0.065 (0.110)	−0.213 (0.110)		0.062 (−0.026)
VEGF	−0.003 (0.115)	0.000 (−0.017)	0.048 (0.115)	−0.219 (0.115)		0.056 (0.025)



Relationship between aerobic fitness and subsequent recognition memory
Predictor	Unadjusted		Adjusted
Predictor	β^a_fitness	R²^b	β^a_fitness	β^c_sex	β_{RER ≥ 1.15}	R²^b

Fitness	−0.002 (0.112)	0.000 (−0.016)	0.008 (0.118)	−0.086 (0.125)	0.128 (0.121)	0.020 (−0.029)

Interaction between BDNF and aerobic fitness on subsequent recognition memory
β_{BDNF· fitness}	β^a_BDNF	β^a_fitness	β^c_sex	β_{RER ≥ 1.15}	β^c_{assay round}	R²^b

0.609^** (0.228)	−0.294^** (0.109)	−0.059 (0.105)	--	--	--	0.157 (0.117)
0.587^** (0.222)	−0.252^* (0.106)	0.040 (0.118)	−0.066 (0.116)	0.181 (0.113)	−0.262^* (0.113)	0.232 (0.158)

This table presents a series of beta regression models with and without adjusting for confounding covariates; each row corresponds to a different model predicting SMT accuracy. Coefficients are presented as β (SE_β). Exponentiated coefficients can be interpreted as odds-ratios

Continuous input variables were standardized prior to model estimation (see Methods for details)

Beta regression pseudo-R² (ordinary least squares regression adjusted-R²for comparison)

Positive values on the coefficient for assay round reflect higher outcomes for assay wave two; positive values on the coefficient for sex reflect higher outcomes for male subjects

P < 0.05

^**

P < 0.01

^***

P < 0.001