Israel’s incidents of the blood cancer are among the highest in the world. Israeli women have the highest age-standardized rate of the disease, while Israeli men have the second highest, according to 2012 estimates by the Global Cancer Observatory. The study looked at Israeli-born Jews of both genders between 1960 and 2005.

The discrepancy between the two groups is likely due to differences in lifestyle and environment dating back to people’s childhoods, said Dr. Hagai Levine, an epidemiologist and head of the environment and health track at Hebrew University-Hadassah Medical Center School of Public Health. His findings were published in the journal.

“While we still need further studies to identify the specific causes of the high rates of Hodgkin lymphoma among native Israelis, our findings direct us to search for possible environmental causes in Israel and the neighboring countries,” Levine said, the Jerusalem Post reported. “These causes could be not only environmental exposures, but also diet, climate, social environment. and stress that may be related to chronic regional conflict.”