Table 2. Results from the multiple logistic regression analysis for a positive M. pneumoniae PCR result in the asymptomatic group.

Variable	Odds Ratio (95% CI)	p-Value
Age (≥5 y)	0.96 (0.47–1.96)	0.91
Gender (female)	1.44 (0.81–2.56)	0.22
Season		<0.001 (overall)
Spring versus winter	0.81 (0.33–1.97)	0.64
Summer versus winter	7.43 (3.09–17.85)	<0.001
Autumn versus winter	2.90 (1.26–6.70)	0.01
Year (2009 versus 2010 and 2011)	3.31 (1.75–6.27)	<0.001
Family size (≥5 family members)	1.55 (0.77–3.13)	0.22
Smoking (active or passive)	0.70 (0.38–1.26)	0.23
Presence or history of wheezing	2.30 (0.69–7.61)	0.17
Day-care attendance	0.82 (0.38–1.77)	0.62
RTI prior to enrollment	0.95 (0.50–1.79)	0.86
RTI post-enrollment	0.59 (0.29–1.20)	0.15

The variable “immunizations” was not entered in the regression analysis because the vast majority of the children were immunized (>95%).