. Author manuscript; available in PMC: 2012 Oct 11.

Published in final edited form as: Brain Behav Immun. 2011 May 14;25(6):1272–1278. doi: 10.1016/j.bbi.2011.05.002

Table 2.

Associations between kynurenine levels and characteristics of the study population.

Characteristic	Mean KYN levels (SD) by characteristic		t-score	df	p-value

Sex (male / female)	1.60 (0.30)	1.27 (0.34)	3.95	59	<0.001
Race (white / nonwhite)	1.50 (0.31)	1.3 (0.39)	2.145	58	0.036
Smoker (yes/no)	1.37 (0.38)	1.42 (0.36)	− 0.362	59	0.719

	Correlation with KYN Pearson's r	*F-score*	df	p-value

Age (yrs)	0.04	0.105	1, 59	0.747
BMI (kg*m⁻²)	0.28	4.766	1, 58	0.033*
Education (yrs)	0.07	0.314	1, 59	0.578
HDRS-17^a	0.16	0.762	1, 28	0.390
BDI^a	0.09	0.209	1, 28	0.651
TRP	0.40	11.266	1, 59	0.001*

	TRP correlation with KYN among subgroups

in MDD	0.46	7.535	1, 29	0.01*
In healthy volunteers	0.40	5.576	1, 29	0.025*
in MDD nonattempters	0.73	15.490	1, 15	0.001*
in MDD attempters	0.05	0.167	1, 13	0.87

Abbreviations: BDI, Beck Depression Inventory; BMI, body-mass index; HDRS-17, Hamilton Depression Rating Scale (17-item); KYN, kynurenine; MDD, Major Depressive Disorder; SD, standard deviation; TRP, tryptophan.

Test performed in depressed subgroup only.