SOCIOECONOMIC-STATUS, MIGRATION AND THE RISK OF BREAST-CANCER IN ITALY

Background. High socioeconomic status and migration to a higher risk a rea have been linked to increased breast cancer risk. To evaluate the occurrence of breast cancer in women of different social class and res idential history, we conducted a multicentre case-control study in Ita ly. Methods. A total of 2569 cases of incident breast cancer were asce rtained in northern, central and southern Italy. The controls were 258 8 women admitted for a wide spectrum of acute conditions to the same h ospitals where cases had been hospitalized. The effect of socioeconomi c variables was evaluated with multiple logistic regression after stra tification and adjustment for age, origin, centre, and selected reprod uctive and dietary factors. Results. Compared to housewives, managers and professionals had a 1.7-fold increased risk, whereas the relative risk was 0.7 and 0.6 respectively in helpers and manual workers. The r isk of breast cancer also increased with increasing social level of th e husband's occupation and subject's number of years of schooling. Wom en who originated in central and southern Italy, and migrated to north ern Italy after age 24, but not those who migrated at a younger age, h ad a relative risk of 0.6 and 0.7 respectively, compared to lifelong r esidents in northern Italy. Conclusions. Our findings show that correl ates of sociocultural level and place of origin exert an influence on breast cancer risk which is not accounted for completely by known risk factors (i.e. reproductive and menstrual characteristics and recent d ietary habits). Such influence may thus occur early in life.