Jewish survivors of World War II who were potentially exposed to the Holocaust are at higher risk for cancer occurrence, according to a new study published in the Journal of the National Cancer Institute. Previous studies in non-Jewish populations investigating the relationship of cancer incidence rates to physical and psychological stress, such as famine and mental stress, have reached similar results.
To further investigate the relationship, Lital Keinan-Boker, M.D., Ph.D., MPH, of the School of Public Health, Faculty of Welfare and Health Sciences, at the University of Haifa in Israel, and colleagues compared the cancer rates in a cohort of over 300,000 Israeli Jews who were born in Europe and immigrated to Israel before or during World War II (the non-exposed group) with cancer rates in a cohort of European-born Israeli Jews who immigrated from Europe after World War II and up to 1989 (the exposed group, those potentially exposed to the Holocaust). Exposure was based on immigration dates because no individual data were available on actual Holocaust exposure.
Likely exposure, compared with non-exposure, was associated with statistically significantly increased risk for overall cancer risk (all cancers combined) for all birth cohorts, and for both sexes. The strongest associations were with breast and colorectal cancer. Earlier exposure, i.e., at a younger age, seemed to be particularly associated with increased risk of all-site cancer.
"These observations may have direct impact on the health of World War II Jewish survivors and thus the care required from their caregivers in Israel and elsewhere," the authors write. "These findings warrant further epidemiological studies (such as case–control studies) of past and present risk factors that use individual data."
In an accompanying editorial, Stephen D. Hursting, Ph.D, MPH, of the Department of Nutritional Sciences at the University of Texas, Austin, and Michele R. Forman, Ph.D., of the Department of Epidemiology, University of Texas—MD Anderson Cancer Center in Houston, discuss these results in European-born Israeli Jews and those of several past studies of calorie reduction and cancer risk. They say the data from this study add to the growing body of literature on the effects of severely restricted calorie intake and of unimaginable psychosocial and physical hardships on cancer risk.
"Taken together, data from animal and human studies suggest that while [calorie reduction] typically decreases cancer risk, the anticancer effects of [calorie reduction] may be neutralized or overwhelmed in the presence of extreme stressors," the editorialists write. "From this unique cohort we can learn lessons about adaptation to extreme hardships in early life, resilience during life, and cancer susceptibility later in life."