Infectivity of Mycobacterium tuberculosis Genotypes and Outcome of Contact Investigation in Classroom in Guangxi, China

Table 3

Multivariate ordered logistic regression analysis to choose the best model.

Variables	odel 1	odel 2	odel 3	odel 4	odel 5	odel 6
Index case genotypes	+	+	+	+	+	+
Sex of index case	-	+	+	+	+	+
School types	-	-	+	+	+	+
Sex of contacts	-	-	-	+	+	+
Ethnicity of contacts	-	-	-	-	+	+
BCG scar of contacts	-	-	-	-	-	+
AIC	8762.1	8743.9	8692.0	8692.4	8686.7	8631.5
P-value (Likelihood ratio test)		<0.001	<0.001	0.200	0.010	<0.001

Note: compared to the preceding model; compared to odel 3.