Study finds link between allergies and increased risk of blood cancers in women

A team of scientists looking into the interplay of the immune system and cancer have found a link between a history of airborne allergies - in particular to plants, grass and trees - with risk of blood cancers in women.

Notably, the study did not find the same association in men, which suggests a possible gender-specific role in chronic stimulation of the immune system that may lead to the development of hematologic cancers. The findings are published online ahead of the December print issue of the American Journal of Hematology.

“To the best of our knowledge, ours is the first study to suggest important gender differences in the association between allergies and hematologic malignancies,” wrote first author Mazyar Shadman, M.D., M.P.H., a senior fellow in the Clinical Research Division at Fred Hutchinson Cancer Research Center.

According to Shadman, who led the research, the immune system’s potential role in cancer causation is a focus of intense scientific interest. “If your immune system is over-reactive, then you have problems; if it’s under-reactive, you’re going to have problems. Increasing evidence indicates that dysregulation of the immune system, such as you find in allergic and autoimmune disorders, can affect survival of cells in developing tumors.”

For the study, Shadman, principal investigator Emily White, Ph.D., of the Public Health Sciences Division at Fred Hutch and their colleagues drew on a large, population-based sample of men and women from the VITamins And Lifestyle (VITAL) cohort, which included people aged 50-76 years old from western Washington. The study participants answered a 24-page questionnaire that focused on three major areas: health history and cancer risk factors, medication and supplement use, and diet. Participants provided information on age, race/ethnicity, education, smoking, diet (fruit and vegetable intake), and other lifestyle characteristics, self-rated health, medical history, and family history of leukemia or lymphoma.

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; foods; and medications.

Of the 79,300 VITAL participants who filled out the questionnaires, more than 66,000 individuals were selected after eliminating those who had a prior history of malignancies other than non-melanoma skin cancers and missing information on baseline cancer history.

Participants were followed for a median of eight years until they withdrew from the study, moved away, had a cancer diagnosis other than hematologic malignancy or non-melanoma skin cancer, or died. Incidence of hematologic malignancies and other cancers was identified via the Surveillance, Epidemiology and End Results (SEER) cancer registry of western Washington.

Of the participants, 681 developed 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. 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.