Lucky you… you have allergies

People with allergies, such as asthma and hay fever, have a surprising advantage, according to research at the University of New South Wales (UNSW).

In a report presented at an international conference in Sydney last week, people with an allergic disease were 25% less likely to develop the most common type of non-Hodgkin lymphoma (a cancer of the lymph system). So having asthma or hay fever for a long time may lower your risk of non-Hodgkin lymphoma.

Non-Hodgkin lymphoma becomes more common after 50, is three times as common as in 1950, and is the sixth deadliest cancer in Australia.

"The only strong risk factors we know for non-Hodgkin lymphoma are immune deficiency and certain infections, as seen in uncontrolled AIDS and in organ transplant patients," one researcher said. "So other immune disturbances, such as allergic diseases including asthma, hay fever and food allergy, might be linked with lymphoma, and you'd expect them to raise the risk. The surprise was the opposite." The lower risk was seen only in B-cell non-Hodgkin lymphoma, the most common type.

The biological mechanisms aren't fully known, but the data suggest that multiple, chronic allergies greatly reduce the risk. Research into the genetic and environmental factors behind allergy and its apparent protective effect will improve our understanding of the complex biology involved. The analysis combined 13 studies, with 13,535 people with non-Hodgkin lymphoma and 16,388 healthy controls, and was funded by the Leukaemia Foundation.