A curious study has recently come out that suggests there may be something inherent to the Israeli lifestyle or Israel’s environment that is behind the country’s high rates of the disease. The study in question focused on seeing whether immigration status showed any correlation to the risk of Hodgkin’s lymphoma and found that the primary association was with whether someone was born is Israel, regardless of their parents’ country of origin.
In Brief: Hodgkin’s Lymphoma
Hodgkin’s lymphoma is a type of malignancy of the lymph systems and accounts for about 30% of all tumors in that part of the body. Although lymphomas are not the worst kind of tumor, malignant cancer is never a good thing regardless of type. Starting from the 1960’s, Israel has seen a rise in Hodgkin’s lymphoma cases and it currently has one of the highest rates in the world.
If corrected for age, Israeli females have the highest rate of Hodgkin’s lymphoma worldwide, with Israeli males coming in second. The sheer volume of immigration that took place into Israel since its inception in 1948 has meant there is a large amount of population data which could be used for research purposes. This data was used for the study.
The study looked at 2,285,009 women and men who had medical examinations between 1967 and 2011, all of whom were aged 16-19 at the time of the exam. During the studied period, about 2,093 cases of Hodgkin’s lymphoma were observed. As mentioned earlier, the rate was highest among those who were born in Israel and, rather remarkably, this elevated risk manifested within a single generation.
For example, Western Asia has relatively low rates of Hodgkin’s lymphoma, and this can be seen by looking at those who immigrated to Israel from that region. However, this lowered risk vanishes when looking at those immigrants’ children. The age of the parents when they immigrated did not seem to factor in to this matter, either.
Other than being Israeli-born, the study noted other correlations to the risk of developing Hodgkin’s lymphoma. Being female, having a higher BMI, being taller, or being born more recently showed associations with higher lymphoma risk. The caveat is that correlation does not mean causation and how meaningful any of these findings are was beyond the scope of the study.
What This Means
The Hodgkin’s lymphoma risk increase was primarily seen among the nodular sclerosis subtype, which does further suggest an environmental factor of some kind. The study only looked at Jewish Israelis, so it will be interesting to see how the rates compare to nearby groups like Palestinians.
More research is going to be needed to try and figure out what elements of the Israeli lifestyle, such as diet, climate, societal stressors, prenatal exposures, etc., seem to be at play. Hopefully these findings will help identify the direction that future research can take in order to narrow down the answers to this intriguing mystery.
Levine, H., et al., “Risk of Hodgkin’s lymphoma according to immigration status and origin: a migrant cohort study of 2.3 million Jewish Israelis,” Leukemia & Lymphoma, 2016; http://dx.doi.org/10.1080/10428194.2016.1220552.