House dust mite sensitization is the main risk factor for the increase in prevalence of wheeze in 13-to 14-year-old schoolchildren in Guangzhou city, China

BackgroundLittle is known about time trend of prevalence of asthma and the association between the changing prevalence and allergen sensitization in Chinese children. ObjectiveTo determine the changes in prevalence of asthma and allergen sensitization in schoolchildren over a period of 15years. MethodsA total of 6928 schoolchildren aged 13-14years in 2009 were recruited for the study using the Phase III Protocol of the International Study of Asthma and Allergic disease in Childhood (ISAAC) and 2531 of them underwent skin prick test for seven common aeroallergens. The results were compared with those obtained in the Phase I (1994/95) and III (2001/02) ISAAC studies. ResultsThe prevalence of asthma ever and current wheeze increased from 3.9% and 3.4% in 1994, to 4.6% and 4.8% in 2001 (P<0.001), and to 6.9% and 6.1% in 2009 (P0.008). The prevalence of higher degree of skin response to house dust mites (HDMs) and cat, and atopic index increased significantly in all children in 2010 when compared with those in 2002 (P<0.001). Prevalence of wheeze remained unchanged in subjects without sensitization to any tested allergen including HDMs (P>0.05). Sensitization to HDMs, especially Dermatophagoides Pteronyssinus was associated with increase in prevalence of wheeze. ConclusionThe prevalence of wheeze and sensitization to common aeroallergens in secondary schoolchildren in Guangzhou China has increased significantly since 1994. Sensitization to HDMs is an important risk factor associated with the increase in prevalence of wheeze in this group of population in Guangzhou city.