People who survived the horrors of the Holocaust have an increased risk of multiple different types of cancer, a new study by Israeli researchers has found. The finding may shed light on how widespread extreme trauma can have an impact on the health of populations, ethnicities, and countries as a whole.

The new research, published in the journal Cancer, is one of the most extensive studies to date on survivors of the Nazi concentration camps and cancer. Their investigation followed the health of 152,622 Holocaust survivors for more than 45 years. They compared the rates of cancer between the people granted compensation for suffering persecution during the war and those who were denied compensation. They also compared those born in Nazi-occupied countries and non-occupied countries.

There was a small yet significant increase in cancer among survivors. Cancer was diagnosed in 22 percent of those who were granted compensation, as opposed to 16 percent of those who didn’t receive compensation. Survivors who were granted compensation had a 6 percent higher risk of developing any type of cancer than those who were denied compensation.

They also noted a 12 percent increased risk for bowel cancer and colon cancer, as well as a 37 percent increased risk for lung cancer. However, they did not find any increase in breast cancer and gynecologic cancers among female survivors.

Those born in occupied countries had an 8 percent increased risk of developing any cancer than those born in non-occupied countries, as well as an 8 percent increased risks of colorectal cancer (bowel cancer and colon cancer) and a 12 percent increased risk for lung cancer.

The research was an observational study and did not look at the cause of this link. However, they hypothesize that the increased risk was due to the psychological stress, starvation, overcrowding, and increased risk of infectious diseases.

“The data emphasize the importance of learning about the combined effect of several exposures occurring intensely and contemporaneously on cancer risk, such as those that unfortunately occurred during World War II," Professor Siegal Sadetzki, from the Chaim Sheba Medical Center in Israel, said in a statement. "Such inspection cannot be conducted by experimental studies and could only be evaluated by using observational epidemiological surveys."

A previous study from 2006 also looked at the cancer risk for Holocaust survivors and found similar results. Although they didn’t find a biological mechanism for the study, the authors believe it was strongly tied to the intense malnutrition they had previously suffered.