Do Saharan Dust Days Carry a Risk of Hospitalization From Respiratory Diseases for Citizens of the Canary Islands (Spain)?

BACKGROUND

Saharan dust meets the Canary Islands at the beginning of its westward path across the North Atlantic, exceeding the European daily levels for PM10; for this reason, their two provincial capital cities, constitute optimal sites where to evaluate the health effects of this natural event.

OBJECTIVES

To assess the short-term association between Saharan Dust Days (SDDs) and respiratory morbidity in the two capital cities.

METHODS

We carried out a time-series analysis with daily emergency hospital admissions due to all respiratory system diseases, chronic obstructive pulmonary disease (COPD) and asthma between 2001 and 2005, assessing the independent effect of SDDs, defined according to the application of the methodology accepted by the European Environmental Office. We also examined accumulated effect, and some other specific SDDs' features.

RESULTS

We found a short-term association between SDDs and the increase in admission risk for the three outcomes during concurrent SDDs, compared to non-SDDs, that spread from 0 to 5th day: 22.6% (95% confidence interval [CI], 10.4, 36.0) for all respiratory diseases and 29.9% (95%CI: 6.6, 58.4) for COPD in Santa Cruz de Tenerife, and 33.4% (95%CI: -2.1,82.0) for asthma in Las Palmas de Gran Canaria. We obtained a robust association when Saharan dust transported at low altitude, when SDDs belonged to long episodes (≥5days), from the fifth SDD onwards and those SDDs with medium (50<PM<150) or high (≥150) PM10 levels.

CONCLUSIONS

We found evidence that SDDs carry a risk of emergency hospital admission from respiratory diseases in the Canary Islands.