After publication of this work [1] it was brought to our attention that the map of Barcelona in Figure two (figure 1 here) was reversed. The final correct Figure is presented here.

Figure 1
figure 1

(Figure two in original manuscript): Cancer mortality (smoothed Standardized Mortality Ratios) by census tract in men (top) and women (bottom) in Barcelona, Madrid, Sevilla, Córdoba and Vigo.

We regret any inconvenience that this inaccuracy may have caused.