Table 2. Distribution of Demographic and Risk Factors in OSCC Patients and Controls.

Characteristic			Cases (n = 325)
	Controls* (n = 335)		Overall OSCC		SCCOP		SCC of oral cavity
	No.	%	No.	%	No.	%	No.	%
Age, years
<40	27	8.1	31	9.5	17	9.0	14	10.2
41–55	105	31.3	126	38.8	86	45.8	40	29.2
56–70	154	46.0	119	36.6	64	34.0	55	40.2
>70	49	14.6	49	15.1	21	11.2	28	20.4
Sex
Male	269	80.3	241	74.1	155	82.4	86	62.8
Female	66	19.7	84	25.9	33	17.6	51	37.2
Tobacco smoking
Ever	239	71.3	227	69.8	125	66.5	102	74.4
Never	96	28.7	98	30.2	63	33.5	35	25.6
Alcohol drinking
Ever	240	71.6	250	76.9	150	79.8	100	73.0
Never	95	28.4	75	23.1	38	20.2	37	27.0
HPV16 serologya
Positive	42	12.5	100	30.8	87	46.3	13	9.5
Negative	293	87.5	225	69.2	101	53.7	124	90.5

^*Controls were selected to be frequency matched to cases on the factors shown in the table.

^aThere was a significant difference in HPV16 serology between the cases and controls.