Table 5– Adjusted change in mean standardised residual^# per 10-fold increase in endotoxin level for forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC) and FEV₁/FVC and endotoxin levels for atopics and nonatopics and stratified by CD14 genotype

	CD14/-260 genotype			p-value
	CC	CT	TT	Heterogeneity of effect	Trend of interaction^¶	Test of difference in effect of CD14 on lung function response to endotoxin⁺
FEV₁, adjusted^§
Nonatopics	0.46 (-0.03–0.96) (n=84)	0.08 (-0.21–0.38) (n=191)	-0.39 (-0.78– -0.01) (n=104)	0.028	0.004	0.091
Atopics	1.11 (0.67–1.55) (n=26)	-0.13 (-0.71–0.43) (n=79)	0.16 (-0.67–1.00) (n=41)	0.001	0.273	0.091
FVC, adjusted^§
Nonatopics	0.57 (0.01–1.13) (n=84)	0.004 (-0.31–0.32) (n=190)	-0.45 (-0.82– -0.08) (n=104)	0.008	0.009	0.260
Atopics	0.42 (-0.35–1.20) (n=26)	-0.02 (-0.59–0.55) (n=80)	-0.04 (-0.82–0.73) (n=41)	0.615	0.900	0.260
FEV₁/FVC, adjusted^§
Nonatopics	-0.12 (-0.58–0.33) (n=84)	0.06 (-0.20–0.33) (n=190)	0.28 (-0.07–0.65) (n=104)	0.362	0.194	0.107
Atopics	1.44 (0.60–2.27) (n=26)	0.02 (-0.50–0.55) (n=80)	0.31(-0.25–0.88) (n=41)	0.018	0.221	0.107

Data are presented with 95% confidence intervals. ^#: a male of age 50 yrs and height 180 cm is predicted to have a FEV₁ of 3.8 L using the equation of Quanjer et al. [17]. If his observed FEV₁ is 4 L, then the difference between observed and predicted FEV₁ is 0.2 L. Following standardisation (again using the standard deviation provided by Quanjer et al. [17]), his standardised residual is 0.38. This means the difference between his measured and predicted FEV₁ is 0.38 standard deviations greater than the mean of all of these values.^¶: additive model.⁺: comparing atopics and nonatopics, p-value of hypothesis that a linear effect of a three-way interaction term (endotoxin×CD14/-260C to T×atopy) is equal to 0.^§: confounders were age, sex, smoking status in pack-yrs and household variables (keeping a cat or dog, age of the mattress, presence of mould in bedroom, presence of damp in bedroom, household density and age of home).