We read with great interest the recent paper by Martins et al¹ concerning the influence of socioeconomic conditions on air pollution adverse health effects in elderly people in Sao Paulo, Brazil. These results are very interesting and may promote understandings of which social category of people are most sensitive to air pollution. The authors suggest that socioeconomic deprivation represents an effect modifier of the association between air pollution and respiratory deaths in elderly people for an increase of 10 µg/m³. They conclude that poverty represents an important risk factor that should be taken into account when determining the health consequences of environmental contamination. We agree with these conclusions. Nevertheless, the question is to know if poor people died because they are more ill, or because of inaccessibility (geographical and economic considerations) to the healthcare …