Table 1. Comparison of three Mycoplasma pneumoniae pneumonia epidemics.

Variable	2003-2004 (n=155)	2006-2007 (n=159)	2011-2012 (n=284)	P value
Age (yr)	4.7±2.6	5.5±3.1	5.3±3.7	0.10
Sex, male:female	85:70	70:89	152:132	0.94
Hospital stay (day)	7.0±2.4	6.8±2.6	6.5±2.4	0.10
Seroconverters*	67/155 (43)	53/159 (33.3)	95/284 (33.5)	0.06

Values are presented as mean±standard deviation or number (%).

Each period of epidemics is from March of epidemic year to February of next year.

^*The patients who showed diagnostic IgM antibodies from negative to positive of the cutoff values during hospitalization.