Allergies may raise blood cancer

In contrast to earlier studies, allergic conditions appear to increase, rather than decrease, the risk of leukaemia and lymphoma.Depending on the root cause of allergies, theories predict that allergic conditions may either reduce or raise the risk of cancer. While several studies have looked at the allergy-cancer relationship by comparing people who have cancer to those who do not, there have been few studies that looked at a representative segment of the general population.Researchers from the Karolinska Institute in Stockholm, Sweden, analysed data from a group of 16,539 Swedish twins who were born between 1886 and 1925. The presence of allergic conditions was assessed with questionnaires administered. The group was followed from 1969 to 1999, and cases of cancer were identified. Analysis of the data indicated that hives and asthma appeared to increase the risk of leukaemia by 2.1- and 1.6-fold, respectively. Similarly, eczema during childhood was linked to a 2.3-fold higher risk of lymphoma. The researchers concluded that it is important to clarify how allergic conditions are connected to blood cancers, since the prevalence of allergies is increasing.