OK Ladies – here’s a question for you. If you suffer from seasonal allergic rhinitis who do you go and see?
(a) An allergist
(b) An oncologist
(c) A hematologist
If you answered (a) you’re probably feeling pretty confident right now. After all the more common term for seasonal allergic rhinitis is hayfever and that’s something best managed by an allergist. Right?
Not so fast! Maybe (b) or (c) would have been better choices. You see, a team of scientists looking into the interplay of the immune system and cancer have just found a link between a history of airborne allergies – in particular those 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 were published online last week 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,” says Mazyar Shadman, MD, from the Fred Hutchinson Cancer Research Center.
According to Shadman, who led the research, the immune system’s potential role in the cause of cancer 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.”
The study included a large sample of men and women aged 50-76 years old from western Washington from the VITamins And Lifestyle (VITAL) cohort study. Participants answered a 24-page questionnaire that focused on: (i) health history and cancer risk factors, (ii) medication and supplement use, and (iii) 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 then followed for eight years until they either 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 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.
There was also an increased risk of plasma-cell neoplasms for participants who reported a history of allergies to cats, dogs or other animals. Plasma-cell neoplasms are conditions, both cancerous and noncancerous, in which the body makes too many plasma cells.
When stratified by gender, the incidence of blood cancers in response to these allergens was increased in women but not in men. The reason for this is as yet unknown.
However, Shadman and colleagues warn, “Given the limited number of cases within each sub-type of hematologic cancer, the risk estimates need to be interpreted with caution … and the possibility of chance finding due to multiple testing should be recognized.”
Even so, if you’re a women with allergies, you may want to keep a close eye on your blood work.