Causes of regional differences in air pollution effects are being studied furtherBMJ 1998; 316 doi: https://doi.org/10.1136/bmj.316.7149.1982 (Published 27 June 1998) Cite this as: BMJ 1998;316:1982
- K Katsouyanni, Associate professor,
- G Touloumi, Research fellow
- Department of Hygiene and Epidemiology, School of Medicine, University of Athens, 1.15 27 Athens, Greece
EDITOR—In their letter about the APHEA project's results on the effects of particulate matter and sulphur dioxide on mortality,1 Bobak and Roberts proposed that heterogeneity in the observed effects between eastern and western European cities could be explained by differences in average winter temperature.2 They have calculated Spearman rank correlation coefficients to illustrate this association.
As described in our paper, we investigated the role …