Table 4

OLS regression model results for male age-height standardised FEV₁ by social class of head of household, ambient air quality index quintile and both adjusting for potential confounders

Men aged 16–79: n = 13503	(a) Social class model			(b) Ambient air quality model			(c) Reciprocally adjusted model
*β coefficient of −0.01 shows FEV₁ 1% lower than expected given age and height.
Model α/constant:	0.976			0.977			0.992
Explanatory variables	β*	95% CI	p	β	95% CI	p	β	95% CI	p
Ambient air quality index: Good	Ref group
Poor				−0.023	−0.030, −0.016	<0.001	−0.022	−0.029, −0.016	<0.001
Social class of head of household: I–II	Ref group
III–V	−0.027	−0.034, −0.021	<0.001				−0.027	−0.033, −0.020	<0.001
HSE survey year: 1995	Ref group
1996	0.011	0.004, 0.018	0.001	0.011	0.004, 0.018	0.001	0.011	0.004, 0.018	0.001
1997	0.013	0.005, 0.021	0.002	0.012	0.004, 0.021	0.002	0.013	0.005, 0.021	0.002
Smoking status: Never	Ref group
Former	−0.023	−0.031, −0.016	<0.001	−0.024	−0.032, −0.017	<0.001	−0.024	−0.031, −0.016	<0.001
Current	−0.064	−0.072, −0.055	<0.001	−0.069	−0.077, −0.060	<0.001	−0.064	−0.072, −0.055	<0.001
Passive smoke exposure: No	Ref group
Yes	−0.016	−0.025, −0.006	0.002	−0.019	−0.029, −0.009	<0.001	−0.015	−0.025, −0.006	0.002
Urban-rural category: Urban	Ref group
Rural	0.016	0.008, 0.025	<0.001	0.005	−0.004, 0.015	0.263	0.002	−0.007, 0.012	0.656
Body mass index: <20	Ref group
>20 to 25	0.056	0.039, 0.074	<0.001	0.057	0.040, 0.075	<0.001	0.056	0.038, 0.073	<0.001
<25 to 30	0.056	0.039, 0.073	<0.001	0.056	0.039, 0.074	<0.001	0.055	0.038, 0.072	<0.001
>30	0.025	0.007, 0.043	0.007	0.024	0.006, 0.042	0.010	0.024	0.006, 0.042	0.011
Ever diagnosed with asthma: No	Ref group
Yes	−0.037	−0.048, −0.026	<0.001	−0.037	−0.048, −0.026	<0.001	−0.037	−0.048, −0.026	<0.001
Used inhaler in previous 24 hours: No	Ref group
Yes	−0.201	−0.215, −0.186	<0.001	−0.202	−0.217, −0.187	<0.001	−0.201	−0.215, −0.186	<0.001