Fig. 2From: Relationship between salivary stress biomarker levels and cigarette smoking in healthy young adults: an exploratory analysisCorrelation between salivary stress biomarker levels and the Brinkman index after adjusting for age: cortisol (a), SIgA (b), IL-1β (c), IL-6 (d), and TNF-α (e). R: partial correlation coefficient. The TNF-α level and the Brinkman index were positively correlated (P = 0.036). The SIgA level was weakly positively correlated with the Brinkman index, but statistical significance was not attained (P = 0.067)Back to article page