Table 2. Mutation rate by patient background.

Population	N	Mutation (%)	95%CI	P-valuea
All samples	91	28 (30.8)
Male	59	12 (20.3)	11.0–32.8	0.005
Female	32	16 (50.0)	31.9–68.1
Never-smoker	38	17 (44.7)	28.6–61.7	0.014
Ever-smoker	53	11 (20.8)	10.8–34.1
Adeno	81	27 (33.3)	23.2–44.7	0.166
Non-adeno	10	1 (10.0)	0.3–44.5
Brinkman Index
0	38	17 (44.7)	28.6–61.7	0.055b
1≪500	9	2 (22.2)	2.8–60.0
500≪1000	25	7 (28.0)	12.1–49.4
1000<	18	2 (11.1)	1.4–34.7

^aFisher's exact test (two-sided).

^bχ²-test (likelihood ratio).