Country of origin, age at migration and risk of cutaneous melanoma: a migrant cohort study of 1,100,000 Israeli men.

Cutaneous melanoma (CM) is a common cancer with increasing incidence in many parts of the world where light-skinned populations live. We conducted a large-scale nationally representative migrant cohort study to assess country of origin and age at migration as predictors of CM, controlling for possible confounders. Data on 1,086,569 Israeli Jewish males, who underwent a general health examination before compulsory military service at ages 16-19 between the years 1967-2005, were linked to Israel National Cancer Registry to obtain incident CM up to 2006. Cox proportional hazards was used to model time to event. Overall, 1562 incident cases were detected during 19.3 million person-years of follow-up. Origin was a strong independent predictor of CM. Incidence was higher for European (hazard ratio [HR] = 4.08, 95% confidence interval [CI]: 3.55-4.67) and Israeli origin (HR = 2.92, 95% CI: 2.25-3.79) compared to N. African/Asian origin, adjusted for year of birth, years of education, residential socio-economic position, rural residence and body surface area (or height). Among those of European origin, the adjusted risk was significantly lower for those who immigrated after the age of 10 years (HR = 0.58, 95% CI: 0.45-0.73) but not for younger ages (HR = 1.02, 95% CI 0.84-1.23) compared to Israeli born. The high rates of CM among men of European origin and the almost twofold lower risk among those immigrating after age 10 provide solid support for the deleterious role of childhood sun exposure as a risk factor for melanoma. These findings will serve in directing public health and research efforts.