Author Affiliations: Department of Pulmonology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China (Xu YC, Xu D, Tao XF, Li SX, Tang LF, Chen ZM); Hangzhou Meteorological Bureau, Hangzhou 310051, Zhejiang Province, China (Zhu LJ)

Corresponding Author: Zhi-Min Chen, Department of Pulmonology, Children's Hospital, Zhejiang University School of Medicine, 57 Zhugan Xiang, Hangzhou 310003, China (Tel: +86 571 87061007 ext 61711; Fax: +86 571 87033296; Email: drchenzm@163.com)

doi:10.1007/s12519-011-0318-0

Background: Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of pediatric respiratory infections and the relation of M. pneumoniae pneumonia (MPP) with meteorological factors remains obscure. This study aims to investigate the epidemiological characteristics of childhood MPP and observe if there is a relationship between epidemiological characteristics and meteorological factors in Hangzhou.

Methods: M. pneumoniae DNA in nasopharyngeal aspirates of hospitalized pneumonia children were detected by polymerase chain reaction from January 1, 2007 to December 31, 2009. The positive rates of MPP (MPP rates) in different years, seasons and ages were compared. The relationship between MPP rates and meteorological data, including mean air temperature (ºC), mean relative humidity (%), monthly precipitation (mm) and raining days were analyzed.

Results: In 14 799 pneumonia cases found from 2007 to 2009, the MPP rate was 18.5%. Altogether 1610 boys (16.9%) and 1134 girls (21.4%) suffered from MPP with a significant difference between both genders (χ²=45.68, P<0.001). In children younger than 1 year, 1-2 years, 3-6 years, and older than 7 years, the MPP rates were 9.8%, 21.1%, 44.4% and 61.6%, respectively. The MPP rates were significantly higher in older children than in younger ones (trends test χ²=46.72, P<0.001). In a descending order, the MPP rates in summer, autumn, spring, and winter were 27.8%, 23.9%, 18.0% and 11.6%, respectively (χ²=372.75, P<0.001). The MPP rates in 2007 to 2009 were 12.9%, 19.3% and 23.6%, respectively (trends test χ²=13.72, P<0.001). Of the four meteorological factors, only monthly mean air temperature was included in the multiple linear regression model (P<0.001).

Conclusions: This study showed that the MPP rate was higher in older children than in younger ones. Girls had a higher positive rate of MPP than boys. In Hangzhou, MPP was more prevalent in summer and autumn. Air temperature was the only meteorological factor affecting the prevalence of MPP.

Key words: meteorological factor; Mycoplasma pneumoniae; pneumonia; temperature

                   World J Pediatr 2011;7(3):240-244