Chunk #42 — Methods and results — Testing for significance of gene-environment interaction effects using the reparameterized equation — Extensions of the equation

Source

Testing for measured gene-environment interaction: problems with the use of cross-product terms and a regression model reparameterization solution.

Embedded

yes

Text

A second extension of the model would be to allow for nonlinear interaction effects. These can also readily be incorporated into extensions of the model. For polynomial regression (i.e. polynomial on environment variable) with a three category variable the regression representing all subclasses of the gene variable has the form P∼G+G2+E+G×E+G2×E(linear)+E2+G×E2+G2×E2(quadratic)+E3+G×E3+G3×E3+(qubic)…,+Ek+G×Ek+G2×Ek(k=polynomial).