A comparison of seasonal trends in asthma exacerbations among children from geographic regions with different climates.

BACKGROUND: The fall peak in childhood asthma exacerbations is thought to be related to an increase in viral infections and allergen exposure when children return to school. Whether the seasonality of asthma attacks among children from different geographic regions follows similar trends is unclear.

OBJECTIVE: To compare seasonal trends in asthma exacerbations among school-age children who lived in different geographic locations, with different climates, within the United States.

METHODS: Hospital billing data bases were examined to determine the monthly number of school-age children who were hospitalized or treated in the emergency department (ED) for asthma exacerbations. Data from four cities within three states were compared. Climate data were obtained from archives of the National Climate Data Center, U.S. Department of Commerce.

RESULTS: An annual peak in asthma exacerbations was observed during the fall months (September through November) among children who lived in Charlottesville, Virginia, as well as throughout the state of Virginia. An increase in exacerbations, which peaked in November, was observed for exacerbations among children who lived in Tucson, Arizona, and Yuma, Arizona. In contrast, exacerbations among children from New Orleans, Louisiana, increased in September but remained elevated throughout the school year. Although there was annual variation in the frequency of exacerbations over time, the seasonal patterns observed remained similar within the locations from year to year. A nadir in the frequency of attacks was observed during the summer months in all the locations.

CONCLUSION: Seasonal peaks for asthma exacerbations varied among the children who lived in geographic locations with different climates, and were not restricted to the beginning of the school year.