SAHARAN DUST AND PEDIATRIC ASTHMA IN THE CARIBBEAN

Fine particulate matter (PM), is detrimental to human health, and the PM₁₀ concentration in the Caribbean consistently exceeds the World Health Organization (WHO) guidelines during Saharan dust events. Asthma is a major cause of morbidity in the Caribbean and for unknown reasons the Caribbean has one of the highest rates of pediatric asthma in the world. The objectives of this study are to determine if Saharan dust events result in an increase in the number of asthmatic episodes in the pediatric population of the Eastern Caribbean, the dust mineralogy, and if there is a correlation between mineralogy and asthma incidence. This is the first study undertaking a multi-national analysis in the Caribbean of Saharan dust and pediatric asthma as well as potential mineralogical contribution to asthma risk.

This study examines asthma emergency room admission data for Dominica, St. Lucia, St. Vincent and Grenada for the period January 2015 to December 2017. Saharan dust data was determined by analysis of satellite MODIS data for each of the islands. In addition, dust samples will be collected and characterized chemically and minerologically.

Close to 7000 unique emergency room visits for pediatric asthma were recorded from January 2015 to December 2017. These include Dominica (n=1317), St. Vincent (n=1620) St.Lucia (n=1256) and Grenada (n=1822). More males were affected than females (M:F = 3:2) similar to observations made in previous studies in the region. Dust incidence utilized data retrieved from the NASA MODIS product MYD04_3K, which suffered from wide temporal gaps and limited resolution. The major Saharan dust events occurred during the summer months May to September. Using Spearman rank correlation no significant correlation was observed for the major summer dust events and asthma over the period except for a positive correlation in Grenada in 2016 and in St.Vincent in 2017.

Based on these preliminary results, it appears that there is a significant correlation with out of season dust events but not the summer dust events. Confounding local factors including pollen levels and climatic variables, may also be very influential on asthma incidence. The annual variability in the source and mineralogy of Saharan dust may also contribute; something this study aims to try to identify using samples collected from the islands over the upcoming year.