Site disparities in apoptotic variants as predictors of risk for second primary malignancy in patients with squamous cell carcinoma of the head and neck

Table 1 Distribution of demographic and risk factors in the patient cohorts with index OPC and non-OPC

Variables	Total	OPC (N = 752)			Non-OPC (N = 777)
Variables	No.	SPM (N)	%	p*	SPM (N)	%	p*
Total patients	1529	42	5.6		82	10.6
Age				0.004			0.024
≤ Median (57 years)	770	12	28.6		33	40.2
> Median (57 years)	759	30	71.4		49	59.8
Sex				0.546			0.170
Male	1186	35	83.3		62	75.6
Female	343	7	16.7		20	24.4
Tobacco smoking				0.010			0.037
Ever	1009	22	52.4		69	84.1
Never	520	20	47.6		13	15.9
Alcohol drinking				0.813			0.005
Ever	1099	30	71.4		69	84.1
Never	430	12	28.6		13	15.9
Ethnicity				0.598			0.028
Non-Hispanic White	1333	38	90.5		60	73.2
Other	196	4	9.5		22	26.8
Index cancer stage				0.240			0.035
I or II	386	5	11.9		26	31.7
III or IV	1143	37	88.1		56	68.3
Treatment^a				0.511			0.111
S only	253	0	0.0		19	23.2
S/C/X	335	4	9.5		30	36.6
X/C	941	38	90.5		33	40.2