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Multicentre Study Explains:
¡@¡@The study involved 10,902 children aged 10 years from three cities in China at different stages of modernization, namely Hong Kong, Beijing and Guangzhou. Asthma is one of the most common chronic disorders in children, and its prevalence varies worldwide. Consistent reports from different countries indicate an increase in prevalence of asthma and allergies. This increasing trend cannot be explained by genetic factors. Despite numerous studies in different communities, the factors related to the increasing prevalence of asthma are largely unknown, probably because the factors are so widespread that it is difficult for epidemiological studies to identify them. In China the prevalence of asthma is lower than that in the West, and within China the prevalence varies across regions-for example, over one year, 12.4% and 10.1% of children aged 13 and 14 years in Hong Kong had wheeze compared with 4.2% and 2.0% of children on the mainland. As children from these regions have a similar genetic background, it may be possible to determine the environmental factors associated with asthma, Professor Gary Wong Wing-kin and Professor Leung Ting-Fan of the Department of Paediatrics, CUHK explained the findings of the study. Randomly selected subgroups of children from each city, totalling 3483, underwent a skin prick test for sensitivity to eight common aeroallergens, such as pollen and dust. Researchers then evaluated the association between current wheeze and environmental factors and diet including cooking by gas, foam pillows, cotton quilts, damp housing (mould on ceiling or walls), pets, and contact with cats, dogs, or farm animals and consumption of meat, fruit, cooked green vegetables, and raw vegetables. ¡@¡@The prevalence of wheeze was significantly higher in children from Hong Kong (see table 1). Other symptoms, including speech limiting wheeze and exercise induced wheeze, were also more common in children. Living on the mainland was associated with a significantly reduced risk of current wheeze (see table 3) It was found that factors during the first year of life and currently that were significantly associated with wheeze were cooking by gas, foam pillows, and damp housing; protective factors were cotton quilts, consumption of fruit more than once a day, and consumption of raw vegetables at least once a week (see table 2). ¡@¡@"We have observed that the prevalence of asthma and atopic symptoms is higher in children in Hong Kong than those on the Mainland. Now we identified significant environmental and diet factors that could explain this difference and we may be able to design preventive strategies for this disease," concluded Professor Fok Tai Fai, Dean of the Faculty of Medicine, CUHK. The findings were published in this week's issue of British Medical Journal. This collaborative research project started in 1995 and has secured two RGC earmarked research grants. The project provided a good foundation for the collaboration of the three institutions. The results provided solid and reliable data for further work in the field of asthma epidemiology. With further economic development and modernization in Mainland China, the prevalence of asthma will certainly increase and it is extremely important to determine the factors that are responsible for the development of asthma in Chinese children. Research presentation of the results was awarded the first prize at the Hong Kong Thoracic Society meeting (2003) and the second prize in the Hong Kong Paediatric Society meeting (2002). T |