Study: Women With Allergies Have Increased Blood Cancer Risk

Source: Sebastian Smit, SXC.hu

Women with airborne allergies to plants, different types of grass, and trees may have a moderate increased risk of developing blood cancers, according to a new cohort study. The same effect of was not seen in men with allergies. The results are published in the American Journal of Hematology.

“While no causality can be inferred, these results suggest a possible gender-specific role of chronic stimulation of the immune system for the development of hematologic cancers,” said the authors in their discussion.

Whether responses of the immune system to allergens or autoimmune responses correlate with the development of malignant blood cells is not clear. The link between allergies and hematologic malignancies has been previously analyzed in epidemiologic studies, but results have been inconsistent. Case-controlled studies have demonstrated an inverse relationship, while prospective studies have shown an increased risk of hematologic malignancies in those with allergies.  

In the current study, Mazyar Shadman, MD, MPH, a senior fellow in the clinical research division at Fred Hutchinson Cancer Research Center, and colleagues analyzed a prospective cohort of 66,212 participants between the ages of 50 and 76 in the Vitamins and Lifestyle (VITAL) study. All participants were from the western part of the state of Washington, were enrolled between 2000 and 2002, and were followed through 2009.  

A total of 681 subjects developed a hematologic malignancy during the 8-year follow-up period. The participants diagnosed with these cancers were more likely to be men, to have two or more close relatives with a history of leukemia or lymphoma, and to have reported their health status as low.  

After taking into account factors associated with blood cancer risk, a history of airborne allergy was associated with an increased risk of blood cancer (hazard ratio [HR] = 1.19; P = .039). The link was only for those individuals who had allergies to plants, trees, and grass, and was strongest for mature B-cell lymphomas (HR = 1.5; P = .005). This association was seen in women (HR = 1.47; P = .004), but not men (HR = 1.03; P = .782).

The authors speculate that the increased risk for blood cancer development among women may reflect their inherent lower baseline risk of developing these cancers. But, a biologic explanation is also possible: hormonal effects on an imbalanced immune system may be the reason for the differential results. Further studies are needed to understand whether there is a biologic cause for the observed difference and its mechanism.  

Shadman and colleagues state that common allergy treatments such as antihistamines and leukotriene agonists have not been shown to be linked to oncogenesis and are unlikely an explanation for the observations.

The study was able to analyze a large cohort of participants, however the allergies were self-reported and a detailed analysis of each person’s history of allergies was not available-only current allergies were reported in the study.