November 24, 2013
Hematologic Cancers In Women Linked To Airborne Allergies: Study
redOrbit Staff & Wire Reports - Your Universe Online
Researchers analyzing the interactions between cancer and a person’s immune system have discovered a link between airborne allergies and an increased risk of blood cancers – but only in women.
According to the study, which currently appears online and will be published in the December print edition of the American Journal of Hematology, the link was strongest when a history of allergies to plants, grass and trees was present.
However, there was no such association in men, suggesting that there is “a possible gender-specific role in chronic stimulation of the immune system that may lead to the development of hematologic cancers,” researchers from the Fred Hutchinson Cancer Research Center (FHCRC) explained a statement Thursday.
“To the best of our knowledge, ours is the first study to suggest important gender differences in the association between allergies and hematologic malignancies,” said first author and lead researcher Mazyar Shadman, a senior fellow in the FHCRC’s Clinical Research Division.
Shadman said that investigators are interested in the immune system’s potential role in cancer causation, noting that both over- and under-reactive biological defenses can cause problems. He added that there is mounting evidence that “dysregulation of the immune system, such as you find in allergic and autoimmune disorders, can affect survival of cells in developing tumors.”
Shadman and his colleagues analyzed data from the VITamins And Lifestyle (VITAL) cohort, a study that included people between the ages of 50 and 76 who resided in western Washington. Each participant completed a 24-page questionnaire focusing on three major areas: their health history and cancer risk factors, their medication and supplement use, and their dietary habits.
Other data, including age, race, education level, smoking history, and family history of leukemia or lymphoma were also collected. Likewise, the study authors collected detailed information on each individual’s history of asthma and allergies was also taken, including allergies to plants, grasses or trees; mold or dust; cats, dogs or other animals; insect bites or stings; and foods and drugs.
Out of the nearly 80,000 people who completed the questionnaire, 66,000 were selected for further study after the researchers eliminated those with prior history of malignancies or missing data on baseline cancer history. Each of those individuals were then followed for a median period of eight years, and a total of 681 people went on to develop a hematologic malignancy during the follow-up period.
“These participants were more likely to be male, to have two or more first-degree relatives with a family history of leukemia or lymphoma, to be less active and rank their health status as low,” FHCRC officials said. “A history of allergies to airborne antigens was associated with a higher risk of hematologic malignancies. The most statistically significant association was seen with allergies to plants, grass and trees.”
The study also discovered that a history of grass, tree or plant allergies was “significantly associated” with one of the four major types of lymphoma, mature B-cell neoplasms. Animal-related allergies were also associated with an increased risk of plasma-cell neoplasms (conditions in which the body makes too many plasma cells.) However, the link between these allergens and blood cancer incidence was only found in female subjects, not in males.
“It is tempting to speculate that the additional effect of allergy may reach statistical significance in women because of their lower baseline risk for the development of hematologic malignancies compared to men,” the authors wrote. “However, hormonal effects on the immune system and interactions with carcinogenesis may offer an alternative biological explanation that will require further mechanical studies, in particular if our findings are replicated in an independent study cohort.”