Table 3.

Geographic trends by urbanicity in emergency department visits for heat stress illness in National Environmental Public Health Tracking states, by region, 2005–2010

Region	Urbanicity*
	Large central metropolitan (LCM)	Large fringe metropolitan (LFM)			Small-medium metropolitan (SMM)			Nonmetropolitan (NM)
		IRR	95% CI	p-value	IRR	95% CI	p-value	IRR	95% CI	p-value
Overall†	referent	0.94	0.86–1.02	0.13	1.06	0.99–1.13	0.07	1.41	1.31–1.52	<0.01
Southeast	referent	0.87	0.73–1.05	0.14	1.22	1.06–1.39	<0.01	1.39	1.11–1.74	<0.01
Northeast	referent	0.87	0.75–1.01	0.07	1.17	1.06–1.29	<0.01	1.73	1.55–1.92	<0.01
Southwest	referent	0.83	0.74–0.93	<0.01	1.06	0.93–1.21	0.37	1.49	1.21–1.82	<0.01
West	referent	0.91	0.81–1.03	0.15	0.82	0.70–0.96	0.02	1.90	1.67–2.17	<0.01
Upper Midwest	referent	1.12	0.94–1.34	0.21	0.85	0.71–1.01	0.06	1.14	1.02–1.26	0.02
Ohio Valley	referent	1.09	0.94–1.25	0.26	0.99	0.88–1.10	0.81	1.15	1.03–1.27	0.01

IRR = incidence rate ratio, CI = confidence interval

^*Adjusted for month, year, sex, age group, poverty, and monthly mean of daily maximum heat index

^†Additionally adjusted for climate region