Table 3.

Risk factors for mortality.

Characteristic	Deceased	Total	Univariable			Multivariable
	(n = 3,610)	(n = 5,018)	HR	95% CI	P	aHR	95% CI	P
At colon cancer diagnosis
Male	2,047	2,782	1.09	1.02–1.16	0.01	1.23	1.02–1.48	0.03
Age > 50 years old	2,751	3,771	1.09	1.01–1.18	0.03	1.17	0.97–1.40	0.11
BMI (kg/m2)
<18.5	317	425	1.25	1.10–1.43	0.001	1.54	1.25–1.90	<0.001
18.5–22.9	760	1,200	Ref.	–	–	Ref.	–	–
23.0–24.9	247	434	0.85	0.73–0.98	0.02	0.91	0.72–1.15	0.44
≥25.0	254	469	0.74	0.64–0.86	< 0.001	0.90	0.72–1.12	0.35
Education level
Primary school	675	889	0.92	0.74–1.14	0.44	0.81	0.60–1.11	0.20
Secondary school	247	352	0.83	0.66–1.06	0.13	0.75	0.53–1.05	0.09
Bachelor’s degree or higher	219	350	0.70	0.55–0.90	0.01	0.64	0.45–0.91	0.01
Unlettered	93	128	Ref.	–	–	Ref.	–	–
Behavioral/clinical factors
Smoking history	1,038	1,383	1.10	1.02–1.19	0.01	0.84	0.67–1.06	0.15
Alcohol-use history	1,431	2,309	1.09	1.01–1.18	0.02	1.00	0.79–1.27	0.97
Diabetes	210	271	0.96	0.84–1.11	0.63	–	–	–
Tumor site
Transverse colon	553	728	1.17	1.06–1.28	0.001	0.77	0.56–1.06	0.11
Right-side colon	436	644	0.95	0.86–1.05	0.32	0.64	0.45–0.92	0.02
Left-side colon	2,641	3,646	Ref.	–	–	Ref.	–	–
Pathological subtype
Adenocarcinoma	3,109	4,430	Ref.	–	–	Ref.	–	–
Signet ring cell	78	87	2.15	1.72–2.70	<0.001	3.89	1.96–7.71	<0.001
Neuroendocrine carcinoma	25	33	1.34	0.90–1.98	0.15	1.16	0.47–2.89	0.75
Other/Unspecified	398	468	1.57	1.42–1.75	<0.001	0.74	0.50–1.09	0.13
Cancer stage
Local	1,293	2,056	Ref.	–	–	Ref.	–	–
Regional	906	1,382	1.18	1.09–1.29	<0.001	1.15	0.95–1.40	0.16
Metastasis	1,276	1,382	3.35	3.09–3.63	<0.001	3.35	2.74–4.09	<0.001
Ambient air pollution exposure
PM2.5 ≥ 37.5 μg/m3	1,418	1,684	1.72	1.61–1.85	<0.001	1.96	1.49–2.58	<0.001
PM10 ≥ 55 μg/m3	912	1,064	1.65	1.53–1.79	<0.001	0.89	0.63–1.26	0.53
NO2 ≥ 8.5 ppb	985	1,334	0.94	0.88–1.02	0.13	–	–	–
CO ≥ 410 ppb	1,006	1,181	1.69	1.57–1.82	<0.001	1.30	0.93–1.82	0.12
O3 ≥ 36 ppb	1,650	2,109	1.37	1.28–1.47	<0.001	0.92	0.77–1.11	0.39

Air pollution levels were estimated based on residential exposure between diagnosis and the last follow-up or death. Thresholds for PM_2.5, PM₁₀, NO₂, CO, and O₃ reflect regionally relevant concentrations based on air quality standards and epidemiological data. Bold values are results considered as statistically significant.