The epidemic of lung cancer in Tuscany (Italy): a joint analysis of male and female mortality by birth cohort.

Lung cancer epidemic among males and females was studied at small geographical level in Tuscany Region (Italy), about 3.5 million inhabitants over almost 30 years (1971-1999). The joint analysis of the space-time pattern of relative risk for a given cause on males and females was conducted specifying a series of Hierarchical Bayesian models. Goodness-of-fit, parsimony and robustness under misspecification were used to identify candidate models. We chose birth cohort as relevant time axis and restricted our attention to birth cohorts born between 1905 and 1940. We found very different pattern by gender: the epidemic curve among males had a peak for the birth cohort born around 1930, the younger cohorts being at lower risk. Among females the relative risk was rising almost linearly on the log scale, the younger birth cohorts being at higher risk. Both curves showed two accelerations corresponding to the post-war periods (1915-1929 and 1945-1959), assuming an average age at first exposure of 20 years old. The spatial distribution among the 287 municipalities investigated was characterized by high risks in all industrial areas in males, and limited to large towns in females. The shared spatial clustering component highlighted the historically developed part of the Tuscany Region.