The effect of age at immigration on cervical cancer incidence: a population-based cohort study of 1 486 438 Israeli women.

OBJECTIVE

To clarify the effect of mass migration from a high-risk area (former Soviet Union) to a low-risk area (Israel) on cervical cancer incidence and mortality in Israel and the modifying effect of age at immigration.

METHODS

All women who immigrated to Israel from the former Soviet Union between January 1, 1990 and December 31, 2000 (N=345 202) and all Jewish Israeli-born women who were 0-80 years old on January 1, 1990 (N=1 141 236) were included. Follow-up ended at December 31, 2010 or date of death or date of cervical cancer diagnosis, whatever occurred earlier. Crossing data from the computerized population registry of the Ministry of Interior, the Israel National Cancer Registry and the Central Bureau of Statistics, cervical cancer incidence and mortality and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI) were calculated.

RESULTS

1595 new cases (crude incidence rate 29.71: 100 000 person years) of cervical cancer were diagnosed in immigrants as compared with 6159 cases (crude incidence rate 27.21: 100 000 person years) diagnosed in Israel-born Jewish women. Immigration at an age older than 12 years was hazardous (aHR 1.27, 95% CI 1.19 to 1.35; P<0.001) while immigration at a younger age was protective (aHR 0.62, 95% CI 0.51 to 0.75; P<0.001) for cervical cancer incidence compared with native Israeli women. Cervical cancer mortality was also significantly higher in immigrants compared with Israel-born women with incidence density rates of 1.15 and 0.35 per 100 person years, respectively (P<0.0001).

CONCLUSIONS

Factors related to the acquired causes of the disease at the country of origin are probably at the root of the low incidence of cervical cancer in Israel. Adult immigrants from the former Soviet Union should be managed as a high-risk group.