Spatial cluster mapping and environmental modeling in pediatric inflammatory bowel disease

Table 4 Incidence rate ratios and 95%CIs for the best model explaining inflammatory bowel disease, Crohn’s disease, and ulcerative colitis rates in local health areas of British Columbia, Canada (n = 88)

Variable	Inflammatory bowel disease		Crohn’s disease		Ulcerative colitis
	IRR and 95%CI	P value	IRR and 95%CI	P value	IRR and 95%CI	P value
Average family size	0.467 (0.268–0.816)	0.007b
Average family income			0.912 (0.827–1.006)	0.064
Glyphosate used in alfalfa crops					0.001 (0.000–0.253)	0.024a
Glyphosate used in corn crops					0.828 (0.707–0.974)	0.021a
Glyphosate used in wheat crops					121.196 (2.252–6671.461)	0.019a
Indigenous ethnic origin	0.956 (0.941–0.971)	< 0.001c	0.923 (0.895–0.951)	< 0.001c
Metam used in fruits and vegetables	0.931 (0.892–0.970)	0.001b
NDVI Maximum at 250 m (× 100)	1.060 (1.040–1.082)	< 0.001c	1.038 (1.014–1.062)	0.002b
NDVI Mean at 250 m (× 100)					1.043 (1.013–1.075)	0.006b
NO2			0.952 (0.919–0.986)	0.006b
O3			0.947 (0.909–0.987)	0.010a	1.095 (1.039–1.154)	0.001b
Petroleum oil used in orchards and grapes	1.135 (1.007–1.270)	0.033a	1.159 (1.002–1.326)	0.038a
PM2.5	1.294 (1.113–1.507)	0.001b	1.230 (1.056–1.435)	0.008b
Rural population					0.990 (0.983–0.996)	0.004b
South Asian ethnic origin	1.020 (1.011–1.028)	< 0.001c			1.054 (1.030–1.079)	< 0.001c
UV Summer	0.9993 (0.9990–0.9996)	< 0.001c	0.9997 (0.9993–1.0001)	0.091
UV Winter					0.996 (0.992–1.000)	0.067

^aP < 0.05.

^bP < 0.01.

^cP < 0.001.

IRR: Incidence rate ratio; NDVI: Normalized difference vegetation index; NO₂: Nitrogen dioxide; O₃: Ozone; PM_2.5: Fine particulate matter; UV: Ultraviolet.