Asthma a risk factor for myelodysplastic syndrome


Asthma may contribute to an added risk of developing myelodysplastic syndrome or chronic myelomonocytic leukaemia (CMML), a recent study suggests.

Researchers looked at a cohort of patients with a first-time hospital-based asthma diagnosis to examine whether asthma was directly related to the development of myelodysplastic syndrome. The total study population comprised 75,995 patients with incident asthma and no history of myelodysplastic syndrome or CMML.

Of the patients, 78 and 9 developed myelodysplastic syndrome and CMML, respectively, during 402,892 person-years.

The cumulative risks of developing myelodysplastic syndrome and CMML were 0.02 percent (95 percent CI, 0.01 to 0.04) and 0.07 percent (0.05 to 0.09) during the first year and the first five years of follow-up, respectively.

Myelodysplastic syndrome and CMML had a standardized incidence ratio of 1.6 (1.3 to 2.0) among asthma patients overall, with little difference across subgroups.

The role of allergies in the development of hematopoietic malignancies is unclear. One potential explanation for this association is the antigen stimulation theory, which suggests that the immune system of allergic individuals is perpetually stimulated by allergens, inducing chronic inflammation, stimulation of cell proliferation and, ultimately, increased risk of malignancy. [Cancer Epidemiol Biomarkers Prev 2014;23:1903–1912]