However, the study did not find the same association in men, which suggested a possible gender-specific role in chronic stimulation of the immune system that may lead to the development of hematologic cancers.
According to lead author Mazyar Shadman, a senior fellow in the Clinical Research Division at Fred Hutchinson Cancer Research Centre, 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 tumours," Shadman said.
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 or 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.
The study is published in American Journal of Hematology.