Roni Caryn Rabin of The New York Times reports: An Israeli study, believed to be one of the first of its kind, has found significantly higher cancer rates among European Jews who immigrated to Israel after the Holocaust than among those who left Europe for what is now Israel either before or during World War II.The rates of breast and colorectal cancer were particularly high among those who spent the war years in Nazi-occupied Europe, according to the paper, published Nov. 4 in The Journal of the National Cancer Institute.
The most striking disparity was among those who were youngest during the war. Of the 315,544 subjects in the study, men born from 1940 to 1945 who were in Europe through the war years developed cancer at three and a half times the rate of men the same age who immigrated to Israel during the war; women in Europe throughout the war years were at more than double the risk, the study found.
The question of whether living in camps or under other dire conditions contributed to cancer in later life has long vexed Israeli experts.
“It is a very delicate question,” said Dr. Micha Barchana, director of the Israel National Cancer Registry and the paper’s senior author. “Holocaust survivors are treated like a special population in Israel, and we wanted to be sensitive. They have already been traumatized, and we did not want to traumatize them again.”
Before embarking on the analysis, researchers broached the subject of the research with groups of survivors to assess their reactions, Dr. Barchana said.
Medical experts in Israel have long been intrigued by the discrepancy in cancer rates between Ashkenazi and Sephardic Jews. Even though several genetic mutations associated with increased cancer risk among Ashkenazi Jews have been identified, Dr. Barchana said, they do not entirely explain the cancer gap.
Experts in the United States whose research focuses on the link between life stressors and cancer said the paper was important and interesting, but they cautioned against drawing any conclusions about cancer causes because the war experience subjected Jews to so many different harsh experiences, including severe, sustained malnourishment and exposure to cold and infections and extreme, prolonged psychological stress that continued after the war. Researchers were also not able to control for behaviors that increase cancer risk, like smoking.
In some ways, experts said, the research raises more questions than it answers. “What is it, or can you not even parse it out between the caloric restriction, the exposure to pathogens, the psychological stress or all of those combined,” said Lorenzo Cohen, director of the department of integrative medicine at the University of Texas M. D. Anderson Cancer Center, in Houston.
There was tremendous variation in the experiences of those who survived the war in Europe. The study included Israeli Jews born in Europe from 1920 to 1945 who were under Nazi occupation. Some had lived in ghettos, some had gone into hiding, and others had survived forced labor and concentration camps.
“There is a lot of heterogeneity in the sample,” said Bonnie A. McGregor, a clinical psychologist with the Fred Hutchinson Cancer Research Center, in Seattle, who studies the link between stress and immune function. “It’s very blurry.”
But, Dr. McGregor said, the association between the war experience and elevated cancer rates was very strong, adding, “I don’t think it’s spurious.”
Earlier studies of cancer rates in survivors of famine during World War II have shown mixed results, with Norwegians who lived through short periods of caloric restriction having lower colorectal cancer risk. Survivors of the Dutch famine of 1944 had a higher incidence of breast cancer.
In the new study on European Jews, the number of cancers in survivors of the war increased substantially the younger the survivors were.
Women born in the early 1940s, during the worst conditions, had breast cancer rates 2.4 times higher than women their age who immigrated to what is now Israel during the war. And men born in the late 1930s had colorectal cancer rates 1.75 times higher than their counterparts who migrated earlier.
The results suggest that early life experiences and exposures, including prenatal conditions, may have a long-term impact on growth patterns and the endocrine system, as well as on behavioral responses that could increase susceptibility to some diseases, Dr. Barchana and his co-authors said.
“The people who were older at the time of exposure were less vulnerable later on,” Dr. McGregor said. By contrast, she said, those exposed to severe psychological and physical stressors in infancy and early childhood received less nurturing and were less equipped to deal with the stress, and would “be living with it and re-experiencing it for a greater percentage of their life.”
{NY Times/Noam Amdurski-Matzav.com Newscenter}
