D1.486 - Epidemiological Investigation of Pollen induced Allergic Diseases in China

The incidence of allergic diseases caused by pollen is increasing year by year, affecting 30% - 40% of the population. There is a lack of epidemiological investigations on pollen induced allergic diseases in China.

A stratified, multi - stage, cluster - random sampling epidemiological investigation method was used, combined with skin prick tests (for common inhaled allergens), pollen monitoring (monitoring daily pollen types and quantities), and vegetation surveys. Epidemiological investigations of allergic diseases were conducted in the Inner Mongolia and Zhangbei grassland areas, which have high pollen concentrations.

The prevalence of allergic diseases in the Inner Mongolia grassland areas is 66.67%. The self - reported prevalence of allergic rhinitis is 43.4% and that of confirmed cases of hay fever is 18.5%. The prevalence rate in urban areas is higher than that in rural areas (23.1% vs 14.0%, P<0.001). In the Zhangbei grassland area, the incidence rates of allergic rhinitis, asthma, and rhinitis combined with asthma are 13.9%, 9.8%, and 2.9%, respectively. Research has found that pollen dispersal and the clinical symptoms of hay fever in the northern grassland areas of China show two peak seasons: April in spring and August in summer. The peak period of the clinical symptoms of allergic rhinitis in summer is 2 weeks earlier than that of pollen in summer - autumn, providing patients with the best time window for early prevention. Research has found that as the amount of pollen in summer and autumn sharply increases from July to September, the number of patients with the disease significantly increases, and the more severe the clinical symptoms are, the stronger the correlation between them. Environmental and climatic conditions can affect the prevalence of hay fever. The pollen - related syndrome is positively correlated with temperature and precipitation (RR>1) and negatively correlated with wind speed and air pressure (RR<1). Pollen exposure is the main reason for the peak of the disease incidence, it seems the original text missed this part

The prevalence of pollen allergy diseases is high in northern China, and pollen sensitization is an independent risk factor for allergic rhinitis and rhinitis combined with asthma.