Table 2.

COHb levels in older men: relations to active/passive smoking, heating and cooking fuel, double glazing

			Model 1				Model 2
		current smoking	COHb				COHb
	N	%	Geometric mean	95%	CI	p	Geometric mean	95%	CI	p
Active smoking						<0.0001				<0.0001
Non	1080	-	0.32	0.30	0.33		0.32	0.30	0.33
Ex	1825	-	0.34	0.33	0.36		0.35	0.34	0.36
Pipe or cigar (light)	76	-	0.60	0.50	0.72		0.61	0.50	0.74
Pipe or cigar (heavy)	99	-	1.50	1.28	1.77		1.53	1.29	1.81
Cigarette smoking <5/d	102	-	1.36	1.16	1.59		1.39	1.17	1.64
cigarette smoking 5–10/d	126	-	2.29	1.98	2.65		2.18	1.87	2.53
cigarette smoking 10–20/d	184	-	3.22	2.86	3.63		3.07	2.70	3.48
cigarette smoking >20/d	51	-	3.29	2.62	4.13		3.18	2.52	4.01
Passive smoking						<0.0001				0.2306
No	2620	12.8	0.40	0.38	0.42		0.45	0.44	0.47
Yes	983	34.4	0.66	0.62	0.70		0.47	0.45	0.50
Gas cooking						<0.0001				<0.0001
No	1394	16.3	0.40	0.38	0.42		0.42	0.40	0.44
Yes	2083	20.2	0.51	0.48	0.53		0.48	0.47	0.50
Gas heating						0.7934				0.9968
No	455	21.3	0.46	0.42	0.51		0.46	0.42	0.50
Yes	3074	18.2	0.46	0.44	0.47		0.46	0.44	0.47
Central heating						<0.0001				0.0083
No	340	29.6	0.64	0.57	0.71		0.52	0.47	0.57
Yes	3201	17.5	0.44	0.43	0.46		0.45	0.44	0.46
Double glazing						0.7657				0.8951
Yes	1778	18.6	0.45	0.43	0.48		0.45	0.44	0.47
No	1594	18.9	0.46	0.44	0.49		0.46	0.44	0.48
in part	169	16.9	0.45	0.38	0.53		0.47	0.41	0.53

Model 1: Includes the relevant factor with adjustment for age, time of day, season.

Model 2: Includes the relevant factor with adjustment for age, time of day, season, and other factors which were statistically significant in the univariate analyses

(region, social class, employment status, housing tenure, active smoking, passive smoking, gas cooking, central heating). An interaction term for active smoking*time of day is also included in the model (see text).

p values presented refer to the results of statistical tests of heterogeneity in COHb levels between the explanatory variable categories