Table A6.

Association Between Smoking Status and Risk of a Second Primary Smoking-Associated Cancer Among Survivors of Head/Neck Cancer, by Site

Smoking Status	Oral Cavity				Oropharynx				Other Head/Neck				Larynx
	Second Cancer		HR	95% CI	Second Cancer		HR	95% CI	Second Cancer		HR	95% CI	Second Cancer		HR	95% CI
	No	Yes			No	Yes			No	Yes			No	Yes
Never	198	5	1.00	Referent	123	4	1.00	Referent	149	7	1.00	Referent	72	2	1.00	Referent
Former
< 20 cig/d	143	8	1.92	0.62 to 5.98	108	7	1.31	0.37 to 4.64	106	8	1.84	0.62 to 5.46	154	9	1.92	0.41 to 8.94
≥ 20 cig/d*	122	15	3.58	1.22 to 10.5	152	11	1.29	0.40 to 4.16	120	7	1.34	0.42 to 4.28	173	33	7.20	1.72 to 30.2
Current
< 20 cig/d	81	14	5.22	1.78 to 15.3	85	6	2.81	0.74 to 10.6	83	6	1.47	0.44 to 4.94	159	16	4.06	0.92 to 17.9
≥ 20 cig/d*	61	12	6.29	2.10 to 18.8	84	6	2.38	0.65 to 8.73	58	9	3.59	1.12 to 11.5	142	24	8.20	1.89 to 35.6
P trend†			< .001				.09				.09				< .001

NOTE. Adjusted for age, sex, race, education, body mass index, cohort, time from baseline to first cancer, and follow-up time. Excludes Alpha-Tocopherol, Beta-Carotene Cancer Prevention study, as this cohort was limited to current smokers.

Abbreviations: cig/d, cigarettes per day; HR, hazard ratio.

^*Cigarettes per day was collected as a categorical variable in National Institutes of Health–AARP Diet and Health Study; Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial; and Agricultural Health Study. The maximum number of cigarettes smoked per day in the Iowa Women's Health Study was as follows: lung (stage I): 60; bladder: 40; kidney: 40; head and neck: 40.

^†P trends across joint categories of smoking status and intensity categories were estimated by including the categorical exposure variable in the model as a continuous variable.