Objective: To compare the prevalence of asthma in children aged 0-14 years by the epidemiological survey for children in urban China between the year of 2000 and 2010.
Methods: Cities participated in the national survey of asthma prevalence in urban children aged 0-14 years at 2000 and 2010 were selected. The surveyed sample sizes met the study requirements. Stratified multistage random cluster sampling and unified questionnaire screening were adopted in both surveys of 2000 and 2010. For screening-positive children, asthma was diagnosed by physicians through on-site visits, physical examination, medical records review and auxiliary examination results. Double entry and validation was adopted for all data using Epi-Info software, and analysis was carried out by SPSS V19.0.
Results: Thirty-three cities were selected for this study. The prevalence of asthma was 1.59% in 2000 and 2.11% in 2010, respectively. The highest prevalence of asthma was seen in Hefei and Shanghai respectively in the two surveys, while the lowest prevalence was seen in Xining and Lhasa. The prevalence rate increased in most of the cities, especially in Wenzhou, Shanghai and Xining. The prevalence of asthma in boys was significantly higher than that in girls in the two surveys, with a ratio of 1.67:1 and 1.58:1, respectively. Preschool age (aged 3-6) had the highest prevalence in both surveys, and nearly 80% of the onset was observed before age 6. Regarding the age of disease onset in the 2000 and 2010 surveys, 54.92% and 43.30% were found in infants, 45.08% and 56.70% in preschool and school-age, respectively.
Conclusions: In the recent 10 years, childhood asthma prevalence rate increased significantly in urban China and the prevalence increased 32.70% in children younger than 14 years in 2010 than before. Most cities had a higher prevalence rate than before, but mainly in first-tier cities, provincial capitals and eastern coastal cities. Preschool children showed the highest prevalence of asthma. The age of asthma onset was increasing, with a higher prevalence in preschool and school-age children as compared to 10 years ago.