Table 2.

Gene-Environment Interaction Between Dust Endotoxin Exposure at the Age of 6 Months and CD14 C-260T^a Genotype on Total Serum IgE Levels and CD4⁺ Lymphocyte Numbers at the Age of 1 Year^b

Outcome variable at 1 y of age	Independent variable	All patients (n = 90)		African American patients (n = 48)		White patients (n = 34)
		Independent variable parameter estimate	P value	Independent variable parameter estimate	P value	Independent variable parameter estimate	P value
Total IgEc	Endotoxin	−0.46	.03	−0.39	.22	−0.45	.17
	CD14 C-260T genotype	−0.83	.14	−0.62	.56	−0.67	.38
	Endotoxin × CD14 interaction	0.33	.08	0.42	.24	0.21	.42
CD4+ cells (No.)	Endotoxin	0.14	.02	0.17	.04	0.22	.05
	CD14 C-260T genotype	0.51	.002	0.50	.04	0.47	.048
	Endotoxin × CD14 interaction	−0.16	.005	−0.20	.02	−0.14	.08
CD4+Foxp3+ cells (No.)	Endotoxin	0.04	.71	0.24	.06	−0.03	.88
	CD14 C-260T genotype	0.19	.47	0.87	.03	−0.24	.55
	Endotoxin × CD14 interaction	−0.08	.39	−0.29	.03	0.01	.94
CD4+Foxp3− cells (No.)	Endotoxin	0.15	.02	0.16	.04	0.23	.04
	CD14 C-260T genotype	0.52	.002	0.48	.05	0.51	.04
	Endotoxin × CD14 interaction	−0.16	.005	−0.20	.02	−0.15	.07

^aCD14 C-260T denotes a single nucleotide polymorphism at position −260 resulting in a cytosine (C) to thymine (T) transition.

^bRegression equations are of the form ln(outcome variable) = β₁(endotoxin) + β₂(CD14 genotype) + β₃(endotoxin)(CD14 genotype) or outcome variable = e^{β1(endotoxin) + β2(CD14 genotype) + β3(endotoxin)(CD14 genotype)}, where β represents the individual parameter estimates given in the table. Endotoxin is included as the log_e transformation of measured value in endotoxin units per milligram of dust, and CD14 C-260T genotype is categorized into CC (=0, referent), CT (=1), and TT (=2).

^cFor total IgE, the numbers of children with data are 72, 28, and 39, for all patients, African American patients, and white patients.