Israeli Jews who survived World War Two in Europe have a significantly higher risk for cancer than other Jews, possibly as a result of hardships endured in the Holocaust, researchers said on Monday.
They said their study, published in the Journal of the National Cancer Institute, suggests that stress or other factors such as extreme deprivation may play a role in triggering cancer.
Researchers led by Dr Lital Keinan-Boker at the University of Haifa in Israel compared cancer rates for two groups of European-born Israeli Jews: 258,048 who left Europe after the war and 57,496 who emigrated before or during the conflict.
Both groups have higher incidence rates for cancer than other Jewish and non-Jewish ethnic groups in Israel.
But the researchers found that Jews who spent World War Two in Europe were at least 17% more likely to develop cancer than those who left before or during the war.
The results are important, the researchers said, because many Jews who survived World War Two in Europe were also victims of the Holocaust - the systematic state-sponsored persecution and murder of about 6 million Jews by Germany's Nazi regime and its collaborators.
They endured severe starvation, extreme mental stress and exposure to cold and infectious agents.
"A possible explanation for the differences in cancer incidence observed among the various Jewish ethnic groups may be differences in their specific exposure to the traumas of the Holocaust," Keinan-Boker and his team wrote.
"These observations may have direct impact on the health of World War Two Jewish survivors and thus the care required from their caregivers in Israel and elsewhere."
Among the cancers that were more common were colorectal, breast and lung cancers.
Increased cancer risks were greatest among the youngest - those born from 1940 to 1945. These younger men 3.5 times higher rates of cancer and younger women 2.33 times more.
Cancer higher among youngest
Actual Holocaust experiences could not be determined, said the researchers.
But they said higher cancer rates among the youngest of the World War Two survivors could suggest that the hardship and adversity of the Holocaust raised the risk of cancer risk by altering growth and hormone patterns in children.
The study's assertion that starvation could contribute to higher cancer rates appeared to conflict with other research suggesting that sharp reductions in food intake could extend longevity and curtail cancer risk.
But Stephen Hursting and Michele Forman, US researchers at the University of Texas, US, who wrote a commentary to accompany the Israeli findings, said European Jews exposed to the Holocaust would have faced a host of debilitating factors besides starvation.
"These multifaceted stressful conditions were very different than the experimental conditions characteristic of the majority of the published caloric restriction studies in animal models," Hursting and Forman wrote. - (David Morgan/Reuters Health, October 2009)
SOURCE: Journal of the National Cancer Institute, published online October 26, 2009.