Table 2.

Associations between SLPI concentration^a and risk of HNSCC, ACS Cancer Prevention Study II Nutrition Cohort, 2001–2002

	Overall HNSCC
	Cases (n=60)	Controls (n=180)
	n	n	OR (95% CI)
Unadjustedb
Low SLPI	23	90	1.0
High SLPI	37	90	1.6 (0.9–3.0)
Per 1 unit SLPI (log ng/mL)			1.2 (1.0–1.4)
Adjustedc
Low SLPI	23	90	1.0
High SLPI	37	90	1.5 (0.8–2.9)
Per 1 unit SLPI (log ng/mL)			1.1 (0.9–1.4)
Interactiond,e
Never smokers
Low SLPI	7	42	1.0
High SLPI	3	41	0.5 (0.1–1.9)
Per 1 unit SLPI (log ng/mL)			0.9 (0.6–1.4)
Ever smokers
Low SLPI	16	48	1.0
High SLPI	34	49	2.1 (1.0–4.3)
Per 1 unit SLPI (log ng/mL)			1.2 (1.0–1.5)

^aModels run separately for categorical and continuous SLPI, with categorical SLPI dichotomized at the median among controls (low: <151.57 ng/mL, high: ≥151.57 ng/mL).

^bUnadjusted model: conditional logistic regression model conditioned on matched set, therefore adjusting for the matching factors, race, gender, date of oral rinse collection and birth date.

^cAdjusted model: conditional logistic regression model conditioned on matched set, therefore adjusting for the matching factors, race, gender, date of oral rinse collection and birth date, and additionally adjusted for smoking status (never, ever cigarette smoker).

^dInteraction model: conditional logistic regression model conditioned on matched set, therefore adjusting for the matching factors, race, gender, date of oral rinse collection and birth date, and additionally adjusted for smoking status (never, ever cigarette smoker) and an interaction term between SLPI and smoking status.

^eP-value for the interaction between smoking status and categorical SLPI=0.0635; P- value for the interaction between smoking status and continuous SLPI=0.2116.