Table 6.

Risk of reported health symptoms for 4 levels of carbon monoxide exposure likelihood

CO exposure	Unadjusted odds ratios (95%CI: Low, High)	Odds ratios version 1* (95%CI: Low, High)	Odds ratios version 2* (95%CI: Low, High)	Odds ratios version 3* (95%CI: Low, High)	Odds ratios version 4* (95%CI: Low, High)
Little or no risk	1.00	1.00	1.00	1.00	1.00
D_Low	1.50 (0.72, 3.13)	1.46 (0.70, 3.05)	1.46 (0.70, 3.04)	0.54 (0.15, 1.95)	3.08 (1.20, 7.91)
C_Medium	2.79 (1.13, 6.85)	2.82 (1.14, 7.02)	2.81 (1.14, 6.96)	2.22 (0.66, 7.50)	3.22 (0.84, 12.4)
B_High or A_Very High	3.38 (1.36, 8.43)	3.25 (1.29, 8.22)	3.23 (1.28, 8.15)	0.98 (0.21, 4.63)	9.28 (2.78, 30.98)

*Version 1: adjusted for benefit, number of residents, and presence of pensioners

*Version 2: using "benefit recipient" as clustering variable, and adjusted for "number of residents" and presence of pensioners

*Version 3: in the subgroup who are "in receipt of benefit"

*Version 4: in the subgroup who are "not in receipt of benefit"