BACKGROUND: Although seasonal variation in tuberculosis incidence has been described in several recent studies, the mechanism underlying this seasonality remains unknown. Seasonality of tuberculosis disease may indicate the presence of season-specific risk factors that could potentially be controlled if they were better understood. We conducted this study to determine whether tuberculosis is seasonal in the United States and to describe patterns of seasonality in specific populations. METHODS: We performed a time series decomposition analysis of tuberculosis cases reported to the Centers for Disease Control and Prevention from 1993 through 2008. Seasonal amplitude of tuberculosis disease (the difference between the months with the highest and lowest mean case counts), was calculated for the population as a whole and for populations with select demographic, clinical, and epidemiologic characteristics. RESULTS: A total of 243 432 laboratory-confirmed tuberculosis cases were reported over a period of 16 years. A mean of 21.4% more cases were diagnosed in March, the peak month, compared with November, the trough month. The magnitude of seasonality did not vary with latitude. The greatest seasonal amplitude was found among children aged <5 years and in cases associated with disease clusters. CONCLUSIONS: Tuberculosis is a seasonal disease in the United States, with a peak in spring and trough in late fall. The latitude independence of seasonality suggests that reduced winter sunlight exposure may not be a strong contributor to tuberculosis risk. Increased seasonality among young children and clustered cases suggests that disease that is the result of recent transmission is more influenced by season than disease resulting from activation of latent infection.
BACKGROUND: Although seasonal variation in tuberculosis incidence has been described in several recent studies, the mechanism underlying this seasonality remains unknown. Seasonality of tuberculosis disease may indicate the presence of season-specific risk factors that could potentially be controlled if they were better understood. We conducted this study to determine whether tuberculosis is seasonal in the United States and to describe patterns of seasonality in specific populations. METHODS: We performed a time series decomposition analysis of tuberculosis cases reported to the Centers for Disease Control and Prevention from 1993 through 2008. Seasonal amplitude of tuberculosis disease (the difference between the months with the highest and lowest mean case counts), was calculated for the population as a whole and for populations with select demographic, clinical, and epidemiologic characteristics. RESULTS: A total of 243 432 laboratory-confirmed tuberculosis cases were reported over a period of 16 years. A mean of 21.4% more cases were diagnosed in March, the peak month, compared with November, the trough month. The magnitude of seasonality did not vary with latitude. The greatest seasonal amplitude was found among children aged <5 years and in cases associated with disease clusters. CONCLUSIONS:Tuberculosis is a seasonal disease in the United States, with a peak in spring and trough in late fall. The latitude independence of seasonality suggests that reduced winter sunlight exposure may not be a strong contributor to tuberculosis risk. Increased seasonality among young children and clustered cases suggests that disease that is the result of recent transmission is more influenced by season than disease resulting from activation of latent infection.
Authors: Amy E Millen; Jean Wactawski-Wende; Mary Pettinger; Michal L Melamed; Frances A Tylavsky; Simin Liu; John Robbins; Andrea Z LaCroix; Meryl S LeBoff; Rebecca D Jackson Journal: Am J Clin Nutr Date: 2010-03-10 Impact factor: 7.045
Authors: Elvin Geng; Barry Kreiswirth; Cynthia Driver; Jiehui Li; Joseph Burzynski; Phyllis DellaLatta; Angel LaPaz; Neil W Schluger Journal: N Engl J Med Date: 2002-05-09 Impact factor: 91.245
Authors: R J Wilkinson; M Llewelyn; Z Toossi; P Patel; G Pasvol; A Lalvani; D Wright; M Latif; R N Davidson Journal: Lancet Date: 2000-02-19 Impact factor: 79.321
Authors: Nicholas D Walter; Thomas H Taylor; David K Shay; William W Thompson; Lynnette Brammer; Scott F Dowell; Matthew R Moore Journal: Clin Infect Dis Date: 2010-01-15 Impact factor: 9.079
Authors: Shanna Nesby-O'Dell; Kelley S Scanlon; Mary E Cogswell; Cathleen Gillespie; Bruce W Hollis; Anne C Looker; Chris Allen; Cindy Doughertly; Elaine W Gunter; Barbara A Bowman Journal: Am J Clin Nutr Date: 2002-07 Impact factor: 7.045
Authors: Adrian R Martineau; Friedemann U Honecker; Robert J Wilkinson; Christopher J Griffiths Journal: J Steroid Biochem Mol Biol Date: 2007-01-12 Impact factor: 4.292