. 2023 Jul 28;131(7):077010. doi: 10.1289/EHP12215

Table 4.

Associations of air pollutants with risk of gastrointestinal cancer in individuals with IBD, CD, and UC in the UK Biobanks Study, mean follow-up of 12 y.

Air pollutants in quartiles ( ${μ g / m}^{3}$ )	IBD ( $lowercase italic n equals 4708$ )					CD ( $lowercase italic n equals 1485$ )			UC ( $lowercase italic n equals 3233$ )
Air pollutants in quartiles ( ${μ g / m}^{3}$ )	Cases/person-years	HR (95% CI)^a	p-Value	HR (95% CI)^b	p-Value^c	Cases/person-years	HR (95% CI)^b	p-Value	Cases/person-years	HR (95% CI)^b	p-Value
${NO}_{x}$
Per IQR (15.6)	—	0.98 (0.82, 1.18)	0.843	0.98 (0.81, 1.18)	0.807	—	0.86 (0.56, 1.31)	0.479	—	1.03 (0.83, 1.28)	0.782
Q1 ( $19.7 to less than 34.8$ )	34/14,031	Ref	—	Ref	—	6/4,486	Ref	—	28/9,493	Ref	—
Q2 ( $34.8 to less than 42.0$ )	24/13,964	0.73 (0.43, 1.22)	0.229	0.71 (0.42, 1.20)	0.201	7/4,241	1.36 (0.45, 4.11)	0.591	17/9,697	0.59 (0.32, 1.09)	0.090
Q3 ( $42.0 to less than 50.4$ )	39/13,865	1.16 (0.73, 1.85)	0.521	1.16 (0.73, 1.85)	0.523	14/4,507	2.64 (1.00, 7.00)	0.053	25/9,207	0.90 (0.52, 1.55)	0.695
Q4 (50.4–247.5)	27/14,121	0.89 (0.54, 1.46)	0.640	0.87 (0.52, 1.44)	0.587	2/4,282	0.43 (0.08, 2.14)	0.299	25/9,722	0.96 (0.56, 1.64)	0.873
p-Trend	—	—	0.893	—	0.926	—	—	0.999	—	—	0.825
${NO}_{2}$
Per IQR (10.4)	—	1.04 (0.85, 1.28)	0.695	1.03 (0.84, 1.27)	0.745	—	0.91 (0.58, 1.44)	0.689	—	1.09 (0.86, 1.37)	0.487
Q1 ( $10.0 to less than 23.0$ )	34/13,958	Ref	—	Ref	—	6/4,564	Ref	—	28/9,357	Ref	—
Q2 ( $23.0 to less than 27.9$ )	28/14,003	0.84 (0.51, 1.39)	0.495	0.84 (0.51, 1.38)	0.485	9/4,215	1.75 (0.61, 4.98)	0.295	19/9,665	0.68 (0.38, 1.21)	0.190
Q3 ( $27.9 to less than 33.4$ )	30/14,094	0.90 (0.55, 1.47)	0.681	0.92 (0.56, 1.51)	0.738	10/4,428	1.87 (0.67, 5.24)	0.233	20/9,560	0.72 (0.41, 1.29)	0.272
Q4 (33.4–86.6)	32/13,926	1.02 (0.63, 1.65)	0.947	1.01 (0.62, 1.64)	0.971	4/4,308	0.86 (0.24, 3.11)	0.819	28/9,538	1.04 (0.61, 1.77)	0.874
p-Trend	—	—	0.900	—	0.897	—	—	0.992	—	—	0.845
$particulate matter begin subscript 10 end subscript$
Per IQR (2.3)	—	1.00 (0.81, 1.24)	0.990	1.00 (0.81, 1.24)	0.995	—	0.79 (0.49, 1.25)	0.312	—	1.09 (0.86, 1.39)	0.488
Q1 ( $13.7 to less than 18.0$ )	33/14,017	Ref	—	Ref	—	11/4,270	Ref	—	22/9,672	Ref	—
Q2 ( $18.0 to less than 19.1$ )	30/14,185	0.91 (0.55, 1.48)	0.694	0.91 (0.55, 1.50)	0.711	7/4,648	0.58 (0.22, 1.50)	0.261	23/9,451	1.08 (0.60, 1.93)	0.807
Q3 ( $19.1 to less than 20.3$ )	31/13,985	0.98 (0.60, 1.60)	0.929	0.98 (0.60, 1.60)	0.941	8/4,358	0.78 (0.31, 1.97)	0.602	23/9,512	1.09 (0.60, 1.95)	0.780
Q4 (20.3–28.6)	30/13,794	0.97 (0.59, 1.59)	0.899	0.96 (0.58, 1.58)	0.868	3/4,239	0.31 (0.09, 1.14)	0.097	27/9,485	1.29 (0.73, 2.28)	0.375
p-Trend	—	—	0.974	—	0.943	—	—	0.120	—	—	0.390
$particulate matter begin subscript 2.5 end subscript$
Per IQR (1.3)	—	0.98 (0.79, 1.21)	0.824	0.97 (0.78, 1.20)	0.789	—	0.89 (0.57, 1.40)	0.624	—	1.01 (0.79, 1.30)	0.920
Q1 ( $8.2 to less than 9.3$ )	35/14,077	Ref		Ref		9/4,573	Ref		26/9,427	Ref
Q2 ( $9.3 to less than 9.9$ )	27/13,898	0.78 (0.47, 1.29)	0.331	0.76 (0.46, 1.26)	0.295	6/4,372	0.82 (0.29, 2.36)	0.713	21/9,489	0.77 (0.43, 1.37)	0.372
Q3 ( $9.9 to less than 10.6$ )	35/13,898	1.03 (0.65, 1.65)	0.886	1.03 (0.65, 1.66)	0.887	9/4,245	1.30 (0.50, 3.35)	0.593	26/9,549	0.99 (0.57, 1.71)	0.977
Q4 (10.6–20.7)	27/14,108	0.82 (0.50, 1.36)	0.438	0.80 (0.48, 1.33)	0.394	5/4,325	0.69 (0.23, 2.12)	0.521	22/9,654	0.85 (0.48, 1.50)	0.573
p-Trend	—	—	0.698	0.97 (0.82, 1.13)	0.662	—	—	0.786	—	—	0.788

Note: —, no data; BMI, body mass index; CD, Crohn’s disease; CI, confidence interval; HR, hazard ratio; IBD, inflammatory bowel disease; IQR, interquartile range; ${NO}_{2}$ , nitrogen dioxide; ${NO}_{x}$ , nitrogen oxides; PM, particulate matter; $particulate matter begin subscript 2.5 end subscript$ PM with aerodynamic diameter $less than or equal to 2.5 micrometers$ ; $particulate matter begin subscript 10 end subscript$ , PM with aerodynamic diameter $less than or equal to 10 micrometers$ ; Ref, reference; UC, ulcerative colitis.

^{^a}

Based on Cox proportional model adjusted for age, sex, ethnicity.

^{^b}

Based on Cox proportional model adjusted for age, sex, ethnicity, assessment centers, household income, smoking status, education, BMI, physical activity, healthy diet, alcohol consumption, baseline related surgery history, medication (use of nonsteroidal anti-inflammatory drugs, amino salicylates, corticosteroids, and immunomodulators).

^{^c}

$p$ -Value $less than 0.05$ was considered statistically significant.