Table 1 Injury episodes and rate comparisons by urban–rural status, National Health Interview Survey 1997–2001.

	Adult population in thousands	Injury episodes in thousands	Rate per 1000 (95% CI)	Rate ratio(95% CI)
Large urban*	97 879	9637	98.5 (94.8 to 102.2)	1.0
Small urban	60 787	6442	106 (100.7 to 111.3)	1.08 (1.05 to 1.10)
Suburban	23 744	2740	115.4 (106.6 to 124.2)	1.17 (1.13 to 1.21)
Rural	17 132	2134	124.5 (113.3 to 135.7)	1.26 (1.22 to 1.31)
Totals	199 542	20 951	105 (102.3 to 107.7)

*Significant contrast p values between large urban and small urban (p = 0.003), large urban and suburban (p = 0.005), large urban and rural (p = 0.006), small urban and suburban (p = 0.005), small urban and rural (p = 0.006) and suburban and rural (p = 0.007). Each contrast reflects the difference between the two rates. The test assesses whether the contrast is significantly different from zero.