Daily Fungal Spores Levels and Numbers of Asthma Hospital Admissions in Southern Taiwan

Abstract

P-121 Abstract: Many fungi produce allergenic proteins triggering hypersensitivity response in susceptible population and exposure to selected fungi is also implicated with symptoms of asthma and other allergic illness. Although airborne fungi is prevalent in most outdoor environments, the burdens of illness attributable to fungus-induced asthma in population remains unknown for most parts of the world. This study has analyzed, using generalized addictive models with Poisson regression model, the associations between the levels of daily fungal spores and frequencies of daily hospital admission in a major teaching hospital from 1 January to 31 December in 2002 in southern Taiwan. Time-series analysis, having filtered the seasonal trends and adjusted for the day-of the week cycles, weather factors, and air pollutants, was conducted to determine the influence of ambient spores on asthma hospital admissions. Numbers of daily visits to asthmatic clinic ranged from 0 to 70, with an average of 23. Cladosporium, the most predominant fungal genera in air comprising up to 70% of total fungal spores in study region, has independent effects on daily asthma visits for the effect only slightly changed in magnitude when adjusting for levels of individual air pollutant and number of visits to clinics of respiratory infections. The strongest association was observed at a time-lag of 2 days for effect of ambient Cladosporium concentrations on the number of clinical visits for childhood asthma (0–14 years old), and at a time-lag of 3 days for asthmatic visits by adults and the elderly. Children appeared to be more sensitive to the day-to-day changes of ambient Cladosporium spore counts; about 8.9% increase in childhood asthma visits with per 1000 spores/m3 increase in airborne levels. In contrast, only about 1.4% to 2.7% increases in the number of visits to asthmatic clinics by populations of 15–39, 40–64, and those above 65 years old. Our study attempted to assess the burden of illness, namely fungus-induced asthma, in the population of southern Taiwan. The concentrations of airborne Cladosporium spore counts alone appeared to account for a significant proportion of clinical asthma visit, and childhood asthmatics seemed to be more sensitive to changes of daily fungal spores than the rest of the general population across different age groups. The effect of exposure to ambient fungal spores on the increasing number of visits remain even after controlling for the levels of different air pollutants and number of clinical visits for respiratory infectious diseases.