Table 6.

Association between principal component analysis factor scores and AOM

PCA factor and group	OR (95% CI) by antibiotic use in past 6 monthsa
	Yesb	Noc
Factor 1
Healthy (refd)	1.0	1.0
AOM	0.69 (0.39, 1.22)	1.12 (0.73, 1.72)
Factor 2
Healthy (ref)	1.0	1.0
AOM	0.46 (0.25, 0.85)	1.18 (0.70, 1.99)
Factor 3
Healthy (ref)	1.0	1.0
AOM	1.97 (0.65, 6.01)	0.66 (0.36, 1.21)
Factor 4
Healthy (ref)	1.0	1.0
AOM	0.63 (0.32, 1.22)	0.51 (0.31, 0.83)

^aBoldface indicates a significant result. Children with URI alone (without AOM) were excluded from the analysis (n = 43 antibiotic users; n = 52 antibiotic nonusers).

^bAntibiotic use in past 6 months: healthy group, n = 18; AOM group, n = 39.

^cNo antibiotic use in past 6 months: healthy group, n = 55; AOM group, n = 33.

^dref, reference.