YL Lau, J Karlberg

Parents of 3,618 6-7 years old children from 15 schools randomly selected from the whole of Hong Kong responded to a standard written questionnaire prepared by the International Study of Asthma and Allergies in Childhood (ISAAC) in 1995. Extra questions regarding potential risk factors were also included. The cumulative and 12-month prevalences of wheezing were 16.8% (18.9% boys, 14.5% girls) and 9.2% (10.3% boys, 8.1% girls) respectively. The corresponding figures for rhinitis symptoms were 38.9% (42.2% boys, 35.4% girls) and 35.1% (38.8% boys, 31.3% girls) respectively. There was a significant monthly variation of the prevalence of rhinitis symptoms. Multiple regression analysis revealed rainfall was the climatic factor associated with this variation (p=0.0001); the lowest prevalence being in June (3.7%) and highest in February (15.3%). The cumulative and 12-month prevalences of itchy rash were 5.7% and 4.2% respectively, with no significant difference between 2 sexes. The cumulative prevalence of eczema was however 28.1%. The 12-month prevalence of wheezing was significantly associated with rhinitis symptoms (OR 6.8), itchy rash (OR 3.5), more severe rhinitis (OR 5.2) and more disturbed sleep due to itchy rash (OR 4.5). In a stepwise logistic regression analysis, 4 significant factors were associated with wheezing:

(i) parental wheezing (one or both parents, OR 4.5)
(ii) URTI (>.4 per year, OR 3.0),
(iii) born in Hong Kong (OR 2.3) and
(iv) male (OR 1.5).

The prevalence of asthma and allergies seems to have increased compared to previous studies in Hong Kong, though different methodologies preclude direct comparison.