Relative risks in 2×2×2 tables, as used in tables 2 and 4

 Separate condensed tables of hazard distances are assembled for birth and death addresses, each showing near and far classes for hazard-Y and hazard-X, as below. (0.5 km in example) Birth addresses Death addresses Hazard-X Hazard-X Near Far Near Far Hazard-Y Near a b Hazard-Y Near e f Far c d Far g h Example Bus station Bus station ⩽0.5 >0.5 ⩽0.5 >0.5 BUT ⩽0.5 184 1224 BUT ⩽0.5 18 689 >0.5 162 3558 >0.5 43 4378 Odds ratios serve here as estimators of the relative risks (RR) of birth proximities. ORs for different situations are listed below
Example
OR(CI)*
*Confidence intervals calculated as suggested by Bland and Altman.22
1 OR for nearY in absence of nearX  = bh/df2.19(1.97 to 2.42)
2 OR for nearY in presence of nearX  = ag/ce2.71(1.51 to 4.89)
3 OR for nearX in absence of nearY  = ch/dg4.64(3.30 to 6.51)
4 OR for nearX in presence of nearY  = af/be5.75(3.52 to 9.42)
5 OR for nearY+nearX v neither  = ah/de12.58(7.74 to 20.45)
6 OR for nearY overall  = {(a+b)(g+h)}/{(c+d)(e+f)}2.37(2.14 to 2.62)
7 OR for nearX overall  = {(a+c)(f+h)}/{(b+d)(e+g)}6.01(4.56 to 7.91)
In the example, both exposures are active (OR = 2.19, 4.64) when outside the effective range of the other; and each is increased (2.71, 5.75) when within range of the other. Finally, comparing double proximities with double non-proximities, the OR for a double exposure is 12.58.