In a new study, researchers looked at almost 17,000 Danish adults who were tested for contact allergies between 1984 and 2008. About one-third (or 35%) tested positive for at least one contact allergy. After looking at the data, the research team determined that women were more likely than men to have a contact allergy — 41% versus 26%. Now here’s where the study gets really interesting. When the research team examined cancer cases among the participants over the long term, they found that men and women with contact allergies had significantly lower rates of breast and non-melanoma skin cancer. Not only that — but women with contact allergies also had lower rates of brain cancer compared to those without contact allergies.
On the downside, people with contact allergies did show higher rates of bladder cancer. The researchers explained this anomaly by suggesting that higher levels of chemical metabolites accumulated in the blood may have contributed to bladder cancer.
Unfortunately, the researchers could not comment on why the link between contact allergies and lower risk for some cancers exists. They hope to perform more research. They do know the link has something to do with the immune system. Perhaps finding the reason for the connection will lead to a better understanding of how the immune system, altered in just the right way, could prevent the growth of cancerous tumors.