Prevalence of childhood asthma, allergic rhinitis and eczema in Urumqi and Beijing

Abstract

Objective: To assess the prevalence of asthma and other allergies in children in Urumqi and Beijing, compared with that in Hong Kong. Methods: A total of 7754 primary school students were randomly selected to participate in the study. Data were collected in 1995-96 using the International Study of Asthma and Allergies in Childhood (ISAAC) protocol for 6- and 7-year-olds. The study design and data quality assurance in all aspects followed the protocol, including the double entry of data. Results: The questionnaire response rate was high (98.9%). Beijing children reported significantly more asthma than those living in Urumqi in three categories: wheezing or whistling in the chest in the past year (6.0%, 95% confidence interval (CI): 5.1-6.9% vs 2.9%. 2.3-3.5%. P < 0.001), sleeping disturbed due to wheezing (1.3%, 0.9- 1.7% vs 0.6%, 0.3-0.9%, P < 0.03) and having experienced asthma ever (10.7%, 9.6-11.8% vs 7.6%. 6.6-8.6%, P < 0.001). The prevalence of allergic thiniris (30.0% vs 31.1% estimated as 12-month nasal symptoms in Beijing and Urumqi, respectively) and eczema (2.8% vs 2.0% recorded as 12-month itchy rash) in the two cities were not significantly different. A similar study was also performed in Hong Kong in 1995 using the same ISAAC protocol. The children in Urumqi and Beijing had fewer (P < 0.05) allergic symptoms compared to those living in Hong Kong (n = 3618). The 12-month prevalence of wheezing, nasal symptoms and itchy rash found in Hong Kong were 9.2% (95% CI: 8.2-10.2%), 35.1% (33.5-36.7%) and 4.2% (3.5-4.9%), respectively. Conclusion: Urumqi, Beijing and Hong Kong represent communities at different stages of westernization and the results from these three cities reflect a worldwide trend for an increasing prevalence of allergies along with westernization. These three cities could assist in identifying risk factors involved in the increase in asthma, allergic thiniris and eczema.