Table 3. Frequency of lung cancer within 5 years of detecting an SPN by chest radiograph stratified by sex, and its distribution according to patient’s characteristics.

	Male					Female
	Total 285	Cancer, n (%) 44 (15.4)	p.value	aRR (CI)	p.value	Total 195	Cancer, n (%) 18 (9.2)	p.value	aRR (CI)	p.value
Age (years)
<50	39	2 (5.1)	0.193	1		37	1 (2.7)	0.325	1
50–59	47	10 (21.3)		3.3 (0.7–15.8)	0.136	38	3 (7.9)		3.1 (0.3–30.4)	0.333
60–69	81	11 (13.6)		2.2 (0.5–10.6)	0.307	52	7 (13.5)		6.8 (0.8–57.8)	0.079
≥70	118	19 (16.1)		2.3 (0.5–10.3)	0.287	68	5 (7.4)		2.8 (0.3–26.2)	0.368
Setting
Inpatient	37	7 (18.9)	0.442	1		14	3 (21.4)	0.061	1
Outpatient	248	35 (14.1)		0.9 (0.4–2)	0.762	181	13 (7.2)		0.2 (0.3–0.9)	0.043
Reason for requesting imaging test
Respiratory	50	12 (24)	0.273	1		36	4 (11.1)	0.247	1
Non-respiratory	74	11 (14.9)		0.7 (0.3–1.6)	0.392	61	4 (6.6)		1.2 (0.2–7.2)	0.827
Extrapulmonary neoplasm	63	7 (11.1)		0.7 (0.3–1.8)	0.458	39	6 (15.4)		14.5 (0.8–28.1)	0.111
Preoperative	35	3 (8.6)		0.6 (0.2–2.1)	0.383	15	0 (0)		0 (-)	0.997
Not available	63	9 (14.3)		0.8 (0.3–1.9)	0.556	44	2 (4.5)		1.2 (0.1–9.7)	0.879
Smoking habit
Never	59	1 (1.7)	<0.001	1		40	5 (12.5)	0.091	1
Former and current	178	38 (21.4)		11.3(1.5–83.3)	0.017	97	10 (10.3)		0.8 (0.2–2.5)	0.641
Not specified	48	3 (6.2)		3.9 (0.4–37.6)	0.243	58	1 (1.7)		——	—
Previous malignancy										0.299
No	174	20 (11.5)	0.194	1		139	10 (7.2)	0.418	1
Yes	111	21(19.8)		1.7 (0.8–3.4)	0.102	56	6 (10.7)		1.9 (0.6–6)
COPD*
No	197	22 (11.2)	0.003	1		161	11 (6.8)	0.300	1	0.487
Yes	88	20 (22.7)		1.7 (1.1–3.2)	<0.001	33	4 (12.1)		1.6 (0.4–6.6)

aRR: adjusted relative risk

*One female patient missing data