Table I.

Frequency distribution of demographic and risk factors in oral cancer cases and controls

Variables	Cases (n = 326)		Controls (n = 349)		P-valuea
	No.	%	No.	%
Age (years)
≤40	31	9.5	37	10.6	0.505
41–55	126	38.7	129	37.0
56–70	119	36.5	141	40.4
>70	50	15.3	42	12.0
Sex
Male	242	74.2	272	77.9	0.259
Female	84	25.8	77	22.1
Tobacco smoking
Ever	227	69.6	242	69.3	0.935
Never	99	30.4	107	30.7
Alcohol drinking
Ever	250	76.7	256	73.4	0.318
Never	76	23.3	93	26.6
p53b
Arg/Arg	183	56.1	181	51.9	0.519
Arg/Pro	121	37.1	144	41.2
Pro/Pro	22	6.8	24	6.9
Arg/Pro + Pro/Pro	143	43.9	168	48.1
p73c
GC/GC	195	59.8	214	61.3	0.919
GC/AT	111	34.1	115	33.0
AT/AT	20	6.1	20	5.7
GC/AT + AT/AT	131	40.2	135	38.7
HPV16
Positive	100	30.7	43	12.3	<0.001
Negative	226	69.3	306	87.7

^aTwo-sided χ² test.

^bP = 0.519 for p53 genotype distributions; P = 0.393 for p53 allele frequency; the observed genotype frequencies among controls were in agreement with Hardy–Weinberg equilibrium (p² + 2pq + q² = 1) (P = 0.518).

^cP = 0.919 for p73 genotype distributions; P = 0.709 for p73 allele frequency; the observed genotype frequencies among controls were in agreement with Hardy–Weinberg equilibrium (p² + 2pq + q² = 1) (P = 0.387).