Association between airborne pollen and epidemic asthma in Madrid, Spain: a case–control study

• Published in: Thorax Vol. 65; no. 5; pp. 398 - 402
• Main Authors: Galán, Iñaki, Prieto, Alicia, Rubio, María, Herrero, Teresa, Cervigón, Patricia, Cantero, Jose Luis, Gurbindo, Maria Dolores, Martínez, María Isabel, Tobías, Aurelio
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Thoracic Society 01.05.2010; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adolescent; Adult; Age Distribution; Aged; Allergens; Allergens - adverse effects; Allergens - immunology; Allergies; Asthma; Asthma - epidemiology; Asthma - etiology; Asthma - immunology; Biological and medical sciences; Cardiology. Vascular system; case-control; Case-Control Studies; Child; Child, Preschool; Chronic obstructive pulmonary disease, asthma; Disease Outbreaks; Emergency medical care; Emergency Service, Hospital - utilization; Female; Histamine; Humans; Male; Medical sciences; Middle Aged; outbreaks; Pneumology; pollen; Pollen - adverse effects; Pollen - immunology; Response rates; Seasons; Skin Tests - methods; Spain - epidemiology; Young Adult; Europe; Spain; Epidemic; Lung disease; Association; Respiratory disease; Bronchus disease; Anesthesia; Pollen; Obstructive pulmonary disease; Circulatory system; Case control study; Cardiology; Asthma
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thx.2009.118992

BackgroundDespite the fact that airborne pollen is an important factor in precipitating asthma attacks, its implication in increases of epidemic asthma in usual meteorological conditions has not been reported. A study was undertaken to estimate the relationship between various types of aeroallergens and seasonal epidemic asthma in the region of Madrid, Spain.MethodsA case–control study was carried out in individuals aged 4–79 years who received emergency healthcare for asthma during 2001 in a base hospital covering a population of 750 000 inhabitants of Madrid. A skin prick test was performed with grass pollen, plantain pollen, olive pollen, cypress pollen, plane tree pollen, dust mites and Alternaria and the prevalence of skin reactivity was compared between subjects with asthma requiring emergency care for asthma within (cases) and outside (controls) the seasonal epidemic period. Data were analysed using logistic regression adjusting for age and sex.ResultsThe response rate was 61.7% for cases (n=95) and 51.6% for controls (n=146). The OR of sensitisation to grass pollen for cases compared with controls was 9.9 (95% CI 4.5 to 21.5); plantain pollen: 4.5 (95% CI 2.5 to 8.2); olive pollen: 7.3 (95% CI 3.5 to 15.2); plane tree pollen: 3.6 (95% CI 2.0 to 6.4); cypress pollen: 3.5 (95% CI 2.0 to 6.2); dust mites: 1.1 (95% CI 0.6 to 1.9); Alternaria: 0.9 (95% CI 0.5 to 1.9). The association with grasses was maintained after adjusting simultaneously for the remaining aeroallergens (OR 5.0 (95% CI 1.5 to 16.4)); this was the only one that retained statistical significance (p=0.007).ConclusionsThese results suggest that allergy to pollen, particularly grass pollen, is associated with the epidemic increase in asthma episodes during the months of May and June in the Madrid area of Spain.