Table 2.

Multivariate risk factor analysis of exposure to Rickettsia felis

	Population	Exposed	Coefficient (SE)	t	P	OR (95% CI)
Constant			0.111 (0.177)	0.625	0.534
Age
20–39 years	34	12	0.033 (0.112)	0.294	0.769	1.033 (0.83–1.286)
40–59 years	27	9	Reference
60+ years	17	0	-0.28 (0.134)	-2.095	0.04	0.756 (0.582–0.982)
State
SA or WA	7	0	Reference
NSW or ACT	21	4	0.132 (0.185)	0.716	0.477	1.142 (0.794–1.641)
QLD	15	3	0.151 (0.194)	0.78	0.438	1.163 (0.796–1.699)
VIC or TAS	32	13	0.323 (0.179)	1.808	0.075	1.381 (0.973–1.96)

Abbreviations: CI confidence interval, OR odds ratio, SE standard error