Saharan dust and daily mortality in Emilia-Romagna (Italy)
- Stefano Zauli Sajani1,
- Rossella Miglio2,
- Paolo Bonasoni3,
- Paolo Cristofanelli3,
- Angela Marinoni3,
- Claudio Sartini1,
- Carlo Alberto Goldoni4,
- Gianfranco De Girolamo4,
- Paolo Lauriola1
- 1Regional Center for Environment and Health, Scientific Direction, ARPA Emilia-Romagna, Modena, Italy
- 2Department of Statistics, University of Bologna, Bologna, Italy
- 3Institute of Atmospheric Sciences and Climate (ISAC), Italian National Research Council, Bologna, Italy
- 4Local Health Authority, Modena, Italy
- Correspondence to Stefano Zauli Sajani, Regional Center for Environment and Health, ARPA Emilia-Romagna, Via Begarelli, 13, 41121 Modena, Italy;
- Accepted 23 November 2010
- Published Online First 16 December 2010
Objective To investigate the association between Saharan dust outbreaks and natural, cardiovascular and respiratory mortality.
Methods A case–crossover design was adopted to assess the effects of Saharan dust days (SDD) on mortality in the Emilia-Romagna region of Italy. The population under study consisted of residents in the six main towns of the central-western part of the region who died between August 2002 and December 2006. The association of Saharan dust outbreaks and PM10 concentration with mortality was estimated using conditional logistic regression, adjusted for apparent temperature, holidays, summer population decrease, flu epidemic weeks and heat wave days. The role of the interaction term between PM10 and SDD was analysed to test for effect modification induced by SDD on the PM10-mortality concentration–response function. Separate estimates were undertaken for hot and cold seasons.
Results We found some evidence of increased respiratory mortality for people aged 75 or older on SDD. Respiratory mortality increased by 22.0% (95% CI 4.0% to 43.1%) on the SDD in the whole year model and by 33.9% (8.4% to 65.4%) in the hot season model. Effects substantially attenuated for natural and cardiovascular mortality with ORs of 1.042 (95% CI 0.992 to 1.095) and 1.043 (95% CI 0.969 to 1.122), respectively.
Conclusions Our findings suggest an association between respiratory mortality in the elderly and Saharan dust outbreaks. We found no evidence of an effect modification of dust events on the concentration–response relationship between PM10 and daily deaths. Further work should be carried out to clarify the mechanism of action.
See Commentary, p 389
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.