Table 5.

Smoking-related characteristics according to the genetic risk group of HNSCC

	Low genetic risk group (0th–24th)	Intermediate genetic risk group (25th–49th)	High genetic risk group (50th–74th)	Very high genetic risk group (75th–99th)	P-value
	(n = 76,502)	(n = 77,180)	(n = 77,142)	(n = 77,668)
Status
Smoking status (UKBB field: 20116), No. (%)					< .001
Never	41,282 (54.2%)	40,837 (53.1%)	40,711 (53.0%)	39,893 (51.6%)
Previous	27,655 (36.3%)	28,229 (36.7%)	28,071 (36.5%)	28,367 (36.7%)
Current	7270 (9.5%)	7834 (10.2%)	8099 (10.5%)	9101 (11.8%)
Current tobacco smoking  (UKBB field: 1239), No. (%)					< .001
No	69,176 (90.5%)	69,291 (89.8%)	68,988 (89.5%)	68,527 (88.3%)
Only occasionally	2001 (2.6%)	1997 (2.6%)	2012 (2.6%)	2096 (2.7%)
Yes	5269 (6.9%)	5837 (7.6%)	6087 (7.9%)	7005 (9.0%)
Amount
Number of cigarettes previously smoked daily (UKBB field: 2887), mean ± SD	19.0 ± 10.5	19.5 ± 10.7	19.4 ± 10.6	19.7 ± 10.8	< .001
Pack years of smoking (UKBB field: 20161), mean ± SD	23.6 ± 18.9	24.1 ± 19.2	24.5 ± 19.5	25.3 ± 19.7	< .001
History
Past tobacco smoking  (UKBB field: 1249), No. (%)					< .001
Smoked on most or all days	18,951 (26.6%)	19,780 (27.7%)	19,716 (27.8%)	20,420 (28.9%)
Smoked occasionally	10,381 (14.6%)	10,178 (14.3%)	10,112 (14.2%)	9833 (13.9%)
Just tried once or twice	11,203 (15.7%)	10,801 (15.1%)	10,621 (15.0%)	10,066 (14.3%)
I have never smoked	30,603 (43.0%)	30,542 (42.8%)	30,584 (43.1%)	30,284 (42.9%)
Maternal smoking around birth (UKBB field: 1787), No. (%)					< .001
No	46,341 (70.3%)	45,699 (68.8%)	44,992 (67.9%)	43,882 (66.0%)
Yes	19,532 (29.7%)	20,716 (31.2%)	21,318 (32.1%)	22,587 (34.0%)
Age stopped smoking  (UKBB field: 2897), mean ± SD	40.3 ± 11.9	40.3 ± 11.9	40.5 ± 11.8	40.7 ± 11.9	< .001
Number of unsuccessful stop-smoking attempts  (UKBB field: 2926), mean ± SD	2.9 ± 7.0	3.0 ± 6.8	3.0 ± 7.9	3.1 ± 7.5	.006

Abbreviations: HNSCC head and neck squamous cell carcinoma, UKBB UK Biobank