Cancer mortality among Polish migrants to France.

Cancer risk in the Polish-born population of France has been compared to that in Poland and in native French subjects (born in France), using mortality data from the period 1979-1985. The Polish-born community in France is a long-established one--most migration occurred during the 1920s--so that for many cancer sites the cancer pattern is closer to that of French natives than that in Poland (eg oral cavity, oesophagus, large bowel, gall bladder, uterus, leukaemia). Polish migrants, however, retain their characteristically high rates of cancer of the stomach and lung (in men), and low rates of breast and prostate cancer. The Polish-born community has a characteristic pattern of residence (living mainly in the Nord and the Pas-de-Calais) and occupational status (a higher proportion of 'workers' than the French-born); these are important confounding factors which can mask the true differences in risk for several sites (larynx, oesophagus, large bowel) if no adjustment is made during analysis.