. Author manuscript; available in PMC: 2008 Mar 20.

Published in final edited form as: Hum Mol Genet. 2006 Nov 29;16(1):36–49. doi: 10.1093/hmg/ddl438

Table 8.

Coding of the gender term g and the genotype term G used in the primary logistic regression model

Genotype	g	G	Odds ratio
AA	0	0	–
aA	0	1	e^β₃
aa	0	2	e^2β₃
AA	1	0	–
aA	1	1	e^β₃ e^β₄
aa	1	2	e^2β₃ e^2β₄

The allele a is the risk allele, the allele more common in cases than in controls. The variable G is defined as the number of copies of the risk allele, and g is 0 or 1 for male or female, respectively. The last column shows the expression for the gender-specific odds ratio for a given genotype compared with the AA genotype, which follows directly from the logistic regression model in Eq. (2).