Air pollution and seasonal asthma during the pollen season. A cohort study in Puertollano and Ciudad Real (Spain)

• Published in: Allergy 2007-10, Vol.62 (10), p.1152-1157
• Main Authors: Feo Brito, F, Mur Gimeno, P, Martínez, C, Tobías, A, Suárez, L, Guerra, F, Borja, J.M, Alonso, A.M
• Format: Article
• Language: English
• Subjects: Adult; Air Pollutants - analysis; air pollution; Air Pollution - analysis; Allergens - analysis; Anti-Asthmatic Agents - administration & dosage; asthma; Asthma - drug therapy; Asthma - epidemiology; Causality; Female; Hospitalization - statistics & numerical data; Humans; Incidence; Male; Middle Aged; Nitrogen Dioxide - analysis; ozone; Ozone - analysis; PM; PM10; Poisson Distribution; Pollen; pollen allergy; Rural Population; Seasons; Severity of Illness Index; Spain; Sulfur Dioxide - analysis; Urban Population
• ISSN: 0105-4538; 1398-9995; 0108-1675
• DOI: 10.1111/j.1398-9995.2007.01438.x

Many studies have demonstrated a positive association between air pollutants and emergency visits for asthma. However, few studies have included pollen when analysing this relationship in mild-moderate asthmatic patients. To determine the importance of the pollutants such as ozone (O₃), particles (PM₁₀), nitrogen dioxide (NO₂) and sulphur dioxide (SO₂) in the clinical course of mild-moderate pollen-allergic asthmatic patients from two Spanish towns in La Mancha: Puertollano (high pollution levels) and Ciudad Real (low pollution levels). We used a Poisson regression model to study a cohort of 137 patients from Puertollano and Ciudad Real during two pollen seasons (2000-2001) and analysed the relationship between air pollutant and pollen levels and daily symptoms, the medication used and peak-flow measurements. The number of asthma symptoms and the mean values of the PM₁₀, SO₂ and NO₂ levels were higher in Puertollano than in Ciudad Real. In Puertollano, the risk of asthma increased by 6% with a 3-day lag for PM₁₀, by 8% with a 3-day lag for O₃, by 4% with a 1-day lag for SO₂ and by 15% with a 3-day lag for O₃ when its values exceeded the health threshold (P < 0.05). The air pollution levels in Puertollano were associated with an increased risk of asthma symptoms in pollen-allergic asthmatic patients com pared with a similar group from Ciudad Real.