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A2808 - Periodicity of Drought and Asthma in the United States of America
Author Block: G. Viegi1, S. Bonomo2, N. Pelosi3, A. Provenzale4, F. Lirer3, S. La Grutta2; 1Pulmonary Environmental Epidemiology Unit, CNR Institute of Clinical Physiology, Pisa, Italy, 2Institute of Biomedicine and Molecular Immunology, National Research Council of Italy, Palermo, Italy, 3Institute for Coastal Marine Environment, National Research Council of Italy, Napoli, Italy, 4Institute of Geosciences and Earth Resources, National Research Council of Italy, Pisa, Italy.
Rationale: The global environment has been facing large changes during the last century, which can also affect respiratory health with increased asthma frequency worldwide. According to McCabe et al. (2014), spatial and temporal variances in multidecadal drought frequency over the contiguous US are attributable to the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) interaction. In view of the statement of the Global Asthma Network “Environmental factors are much more likely than genetic factors to have caused the large increase in the numbers of people in the world with asthma, but we still do not know all the factors which may be important and how they interact with each other” (Report 2014), we hypothesized that drought and asthma mortality may show similar periodicity in the contiguous US. Methods: Annual data (from 1950 to 2015) of asthma mortality (all genders: 5-14 year; 15-24 year; 25-34 year; 35-44 year) were downloaded from the US National Center for Health Statistics. AMO and PDO data were downloaded from the National Oceanic and Atmospheric Administration. The analysis of the non-stationary and non-linear signals was performed by applying the Empirical Mode Decomposition algorithm of Huang et al. (1998) in order to decompose multi-component signals into a series of amplitude and frequency modulation waves to search characteristic periodicities. To compare the dominant periodicities recorded in the asthma mortality data with the same-order periodicities documented in the AMO and PDO, we applied a bandpass filter, using the wavelet multi-level decomposition and reconstruction technique. Results: Asthma mortality data (n/100000) show mean values gradually increasing from the younger to the older age class (5-14yr=0.232; 15-24yr=0.369; 25-34yr=0.562; 35-44yr=1.027). All age class shows increase/decrease trend well comparable to the AMO and PDO trend (i.e. AMO vs 35-44yr; r=0.4 p=0.0006). All data shows a periodicity of ~40/50 year (i.e. AMO periodicity vs 35-44yr periodicity; r= 0.9 p=1.4-25) (Fig.1). Conclusions: Interaction between AMO and PDO, and consequent drought events, show a similar periodicity to asthma mortality in the US. Further research is warranted to elucidate the relationship between the climatic index (interaction of AMO and PDO) and the health outcome (asthma mortality).