Overweight, obesity and risk of haematological malignancies: A cohort study of Swedish and Finnish twins

BackgroundObesity is related to an increased risk of several forms of cancer. However, findings from studies on haematological malignancies are inconsistent.MethodsWe used prospectively collected data from two Swedish twin cohorts and the Finnish Twin Cohort (in total 70,067 persons) to study the effects of overweight and obesity on the development of leukaemia, non-Hodgkin lymphoma, Hodgkin’s lymphoma and myeloma. The cohorts were followed from baseline through 2002 (Sweden) and through 2004 (Finland).ResultsWe found a risk increase of myeloma with a relative risk (RR) of 2.1 (95% confidence interval [CI] 1.1–3.7) among obese persons, a RR of 2.5 (1.0–6.2) for chronic myeloid leukaemia and a RR of 2.7 (0.8–9.6) for acute lymphoblastic leukaemia among overweight persons as compared to normal-weighted ones.ConclusionsOur results add further evidence suggesting that overweight and obesity may have an impact on some haematological malignancies, in particular myeloma.