An additional limit, like many other epidemiological investigations, is the lack of individual data about potential confounding factors such as individual socioeconomic conditions, occupational exposure, and personal lifestyle factors such as smoking habits. Data on socioeconomic status, available at the aggregate level (census tract), allowed us to indirectly take into account other factors related to mortality and/or cancer incidence (i.e. smoking habits and occupational exposure are strongly linked to socioeconomic conditions). In fact, rate ratios estimates were attenuated after adjusting for socioeconomic status (all causes, cardiovascular diseases and some cancer types; data before adjustment are not reported). On the basis of these findings, we cannot exclude the possibility of a residual confounding by socioeconomic status.