BACKGROUND: The 'case-crossover' design is a strategy fitted to studying transient effects of intermittent exposure on acute-onset disease occurring shortly after exposure. It has the important advantage of eliminating most confounding variables, allowing a stronger causality inference. OBJECTIVES: The objective of the study was to evaluate the relationships between emergency room (ER) visits for asthma attacks and gaseous air pollution changes. METHODS: The study included 549 individuals, 3-49 years old, visiting the ER during 1 year. Exposure to gaseous air pollutants (SO2, NO2, O3) on the same day and up to 4 days before was computed according to the patient's address. The statistical analysis included meteorological data as potential confounding variables. RESULTS: No association could be shown between ER visits and SO2 or NO2 levels. In contrast, there was a statistically significant association between ER visits and mean O3 levels, on the day of admission and also on D -2 and D -3. For an increase of 10 microg/m3, the risk of requiring an ER admission increased by 6-10%. CONCLUSIONS: Using this new strategy, we confirmed that ozone changes lead to a moderate increase in risk of requiring an ER admission in asthmatic subjects. Copyright 2004 S. Karger AG, Basel
BACKGROUND: The 'case-crossover' design is a strategy fitted to studying transient effects of intermittent exposure on acute-onset disease occurring shortly after exposure. It has the important advantage of eliminating most confounding variables, allowing a stronger causality inference. OBJECTIVES: The objective of the study was to evaluate the relationships between emergency room (ER) visits for asthma attacks and gaseous air pollution changes. METHODS: The study included 549 individuals, 3-49 years old, visiting the ER during 1 year. Exposure to gaseous air pollutants (SO2, NO2, O3) on the same day and up to 4 days before was computed according to the patient's address. The statistical analysis included meteorological data as potential confounding variables. RESULTS: No association could be shown between ER visits and SO2 or NO2 levels. In contrast, there was a statistically significant association between ER visits and mean O3 levels, on the day of admission and also on D -2 and D -3. For an increase of 10 microg/m3, the risk of requiring an ER admission increased by 6-10%. CONCLUSIONS: Using this new strategy, we confirmed that ozone changes lead to a moderate increase in risk of requiring an ER admission in asthmatic subjects. Copyright 2004 S. Karger AG, Basel
Authors: Perry Elizabeth Sheffield; Jiang Zhou; Jessie Loving Carr Shmool; Jane Ellen Clougherty Journal: Environ Health Date: 2015-03-18 Impact factor: 5.984
Authors: Justin Manjourides; Emily Zimmerman; Deborah J Watkins; Thomas Carpenito; Carmen M Vélez-Vega; Gredia Huerta-Montañez; Zaira Rosario; Ishwara Ayala; Carlos Vergara; Zlatan Feric; Martha Ondras; Helen H Suh; April Z Gu; Phil Brown; José F Cordero; John D Meeker; Akram Alshawabkeh Journal: BMJ Open Date: 2020-07-19 Impact factor: 2.692