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

Table 3.

Associations of air pollutants with risk of enterotomy in individuals with IBD, CD, and UC in the UK Biobank 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)	—	1.11 (1.00, 1.23)	0.059	1.10 (0.98, 1.23)	0.091	—	1.14 (0.98, 1.32)	0.082	—	1.16 (0.96, 1.40)	0.115
Q1 ( $19.7 to less than 34.8$ )	70/13,719	Ref	—	Ref	—	29/4,318	Ref		41/9,503	Ref	—
Q2 ( $34.8 to less than 42.0$ )	56/13,758	0.80 (0.56, 1.13)	0.202	0.72 (0.51, 1.03)	0.071	23/4,159	0.76 (0.44, 1.32)	0.324	33/9,651	0.75 (0.42, 1.35)	0.338
Q3 ( $42.0 to less than 50.4$ )	70/13,541	0.99 (0.71, 1.38)	0.949	0.93 (0.66, 1.29)	0.650	31/4,366	1.03 (0.62, 1.72)	0.911	39/9,212	1.19 (0.69, 2.04)	0.527
Q4 (50.4–247.5)	69/13,823	0.98 (0.70, 1.37)	0.908	0.93 (0.66, 1.30)	0.660	32/4,108	1.04 (0.62, 1.72)	0.892	37/9,751	1.12 (0.65, 1.94)	0.684
p-Trend	—	—	0.791	—	0.975	—	—	0.626	—	—	0.353
${NO}_{2}$
Per IQR (10.4)	—	1.07 (0.94, 1.23)	0.310	1.06 (0.92, 1.22)	0.431	—	1.12 (0.91, 1.37)	0.294	—	1.12 (0.90, 1.40)	0.301
Q1 ( $10.0 to less than 23.0$ )	65/13,706	Ref	—	Ref	—	27/4,413	Ref	—	38/9,379	Ref	—
Q2 ( $23.0 to less than 27.9$ )	53/13,767	0.82 (0.57, 1.17)	0.273	0.77 (0.54, 1.11)	0.167	21/4,147	0.78 (0.44, 1.39)	0.404	32/9,683	1.00 (0.55, 1.83)	0.990
Q3 ( $27.9 to less than 33.4$ )	79/13,691	1.21 (0.87, 1.69)	0.246	1.15 (0.83, 1.60)	0.410	35/4,250	1.25 (0.75, 2.08)	0.384	44/9,476	1.68 (0.98, 2.89)	0.060
Q4 (33.4–86.6)	68/13,677	1.04 (0.74, 1.46)	0.825	0.99 (0.70, 1.39)	0.947	32/4,142	1.15 (0.68, 1.92)	0.609	36/9,579	1.11 (0.62, 1.99)	0.732
p-Trend	—	—	0.358	—	0.515	—	—	0.307	—	—	0.357
$particulate matter begin subscript 10 end subscript$
Per IQR (2.3)	—	1.08 (0.93, 1.24)	0.316	1.07 (0.92, 1.23)	0.388	—	1.15 (0.93, 1.43)	0.185	—	0.99 (0.79, 1.26)	0.960
Q1 ( $13.7 to less than 18.0$ )	56/13,843	Ref	—	Ref		20/4,215	Ref	—	36/9,688	Ref	—
Q2 ( $18.0 to less than 19.1$ )	70/13,824	1.25 (0.88, 1.77)	0.222	1.21 (0.85, 1.72)	0.291	31/4,477	1.56 (0.89, 2.75)	0.122	39/9,415	1.06 (0.61, 1.84)	0.843
Q3 ( $19.1 to less than 20.3$ )	70/13,650	1.27 (0.89, 1.80)	0.185	1.23 (0.87, 1.75)	0.244	33/4,192	1.57 (0.90, 2.75)	0.114	37/9,490	1.27 (0.74, 2.18)	0.391
Q4 (20.3–28.6)	69/13,524	1.23 (0.86, 1.75)	0.251	1.20 (0.84, 1.71)	0.310	31/4,068	1.48 (0.84, 2.61)	0.176	38/9,524	0.97 (0.55, 1.71)	0.908
p-Trend	—	—	0.275	—	0.333	—	—	0.225	—	—	0.919
$particulate matter begin subscript 2.5 end subscript$
Per IQR (1.3)	—	1.16 (1.01, 1.33)	0.030	1.16 (1.00, 1.34)	0.043	—	1.24 (1.04, 1.47)	0.017	—	1.19 (0.95, 1.49)	0.133
Q1 ( $8.2 to less than 9.3$ )	53/13,900	Ref	—	Ref	—	21/4,470	Ref	—	32/9,506	Ref	—
Q2 ( $9.3 to less than 9.9$ )	70/13,601	1.35 (0.94, 1.92)	0.102	1.36 (0.95, 1.95)	0.090	28/4,237	1.37 (0.78, 2.42)	0.275	42/9,423	1.63 (0.90, 2.94)	0.105
Q3 ( $9.9 to less than 10.6$ )	63/13,603	1.21 (0.84, 1.75)	0.297	1.19 (0.82, 1.72)	0.366	23/4,137	1.14 (0.63, 2.07)	0.670	40/9,525	1.56 (0.86, 2.81)	0.142
Q4 (10.6–20.7)	79/13,737	1.51 (1.07, 2.14)	0.020	1.58 (1.09, 2.28)	0.015	43/4,107	2.09 (1.24, 3.54)	0.006	36/9,663	1.51 (0.83, 2.76)	0.176
p-Trend	—	—	0.044	—	0.040	—	—	0.010	—	—	0.249

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.