Prevalence and severity of childhood asthma and allergic sensitisation in seven climatic regions of New South Wales

Abstract

ObjectiveTo compare the prevalence and severity of asthma and of allergic sensitisation in children in different regions. We hypothesised that regions with different standardised hospital admission rates would have different prevalences of childhood asthma and that diverse climates would result in a range of sensitisations to different allergens. Design and settingWe studied large random population samples of children in seven regions in ew South Wales (SW) in 1991‐1993. Hospitalisation rates were obtained from NSW Department of Health data. Participants6394 children aged 8‐11 years. Outcome measuresHistory of respiratory symptoms by selfadministered questionnaire; airway hyperresponsiveness by histamine inhalation test; and sensitisation to allergens by skin‐prick tests. ResultsChildren in all regions had a high prevalence of recent wheeze (22%‐ 27%), of diagnosed asthma (240/0‐38%) and of use of asthma medications (220/0‐30%), but no region was consistently higher or lower for all measurements. The prevalence of current asthma in children living in three coastal regions (where sensitisation to house‐dust mites was high) and in the far west (where sensitisation to alternaria was high) was 12%‐13%, which was significantly higher than the prevalence of7o/o‐lO% in children living in three inland regions (wher e sensitisation to these allergens was lower) (P < 0.01). ConclusionsWe found significant variations in the prevalence and severity of childhood asthma in NSW. The prevalence ofhospitalisations, diagnosed asthma, recent symptoms and medication use may relate to different regional diagnostic patterns, whereas current asthma prevalence may relate to different levels of allergic sensitisation.

Influence of two different geo-climatic zones on the prevalence and time trends of asthma symptoms among Spanish adolescents and schoolchildren

“…As in other studies, the milder climate is a risk factor for asthma symptoms (Hales et al 1998; Laor et al 1993; Zanolin et al 2004). This fact seems to be related to a larger mite load (Charpin et al 1991;Peat et al 1995). In fact, the concentration of house dust mites in Spain was much higher in the coastal cities than in the interior ones on a mite map produced in 1998 (Barber et al 1998).…”

Sunny hours and variations in the prevalence of asthma in schoolchildren according to the International Study of Asthma and Allergies (ISAAC) Phase III in Spain

“…Similarly, it is known that in the interior zones with dry, sunny climates the prevalence of asthma is low compared to hot, humid, coastal zones (Peat et al 1993;Bener et al 1993;Laor et al 1993). In general, the sensitisation to house dust mite is higher in coastal regions than the inland regions and pollen sensitisation is higher inland than in coastal regions (Peat et al 1995;Li et al 2009). In Spain, García-Marcos et al.…”

Reliability of measures of spores of Alternaria and pollen concentrations in air over two towns in rural Australia

“…The towns in rural New South Wales, Australia, were chosen for examination because of high prevalences of atopy to allergens of Alternaria have been recorded in resident children ( Peat et al 1995) . The town of Moree ( population 10,000) is positioned at a latitude of 29 S, and 293 km inland.…”

“…We chose to focus on spores of the fungus Alternaria, and grass and cypress pollen, because of their importance in asthma in rural New South Wales ( Peat et al 1995, Bass et al 1991 . We anticipated that sources of spores of Alternaria and grass pollen would be predominantly from grasslands and crops surrounding the towns.…”