It is notable that the lack of information about residential history before 1990 has limited the possibility of evaluating the effects of duration of exposure and latency since first exposure, two common useful measures in cohort analysis. Finally, as already indicated, power limitations given the size of the population studied may have limited the possibility to provide stable results. In fact, the study was able to detect a relative risk of 1.3 in the last category of exposure for all cancer combined (with α = 0.95 and β = 0.80).