. Author manuscript; available in PMC: 2014 May 5.

Published in final edited form as: Genet Epidemiol. 2013 Jun 24;37(6):581–591. doi: 10.1002/gepi.21744

Table 2.

Analysis results of GEI between HFE genotypes and tibia lead levels in the Normative Aging Study (N=671) using the proposed likelihood ratio test with cell means (LRT-CM) and the parametric bootstrap (LRT-PB) approach (1000 replicates simulated under the null hypothesis)

Model	Hypothesis	p-value
Model	Hypothesis	LRT-CM^a	LRT-CM^b	LRT-PB^a	LRT-PB^b
Model (a)	H₀ : θ = 0	0.008	0.002	0.002	0.003
Model (b)	H₀ : λ_i = 0 (Lead)	0.029	0.007	0.009	0.008
Model (c)	H₀ : η_j = 0 (HFE)	0.015	0.002	0.002	0.001
Model (d)	H₀ : θ = λ_i = η_j = 0	0.035	0.005	0.007	0.002
Model (e)	H₀ : d₁ = 0	<0.10	<0.01	0.009	0.002
Saturated Model	HFE × Lead			0.015	0.006

No covariate adjustment.

Adjusting for baseline age, time since baseline, and squared time. For LRT-CM, residuals from a regression of pulse pressure on all other covariates except lead levels and genotype were used to form the cell means.