Aims and background: We have investigated whether gender differences in cancer incidence have changed during the mid 1980s to late 1990s, and whether certain changes could be clues for gender-specific modifications in carcinogenic exposures.
Methods: We used the incidence data from the Tuscany Cancer Registry and computed the standardized (on the European standard population) male-to-female incidence rate ratios (IRR) for two periods, 1986-87 and 1996-97, with corresponding 95% confidence intervals. Such statistics were calculated for two age groups, 0-59 years and 60 years and over.
Results: Among younger subjects there was a remarkable reduction in the IRR for smoking-related cancer sites such as oral cavity (IRR from 4.3 to 2.2), esophagus (IRR from 6.2 to 4.2), larynx (IRR from 13.3 to 5.7), and lung (IRR from 6.5 to 3.3). Less evident changes were observed among subjects aged 60 and over, eg for lung the IRR fell from 8.1 to 6.2.
Conclusions: Most of the differences examined were probably due to changes in tobacco smoking which were different between genders during the last decade, with a decreasing prevalence of smokers among males and an increasing trend among females.