Anthropometric characteristics, physical activity and risk of hematological malignancies: A systematic review and meta‐analysis of cohort studies

Overweight/obesity, adult attained height and physical activity are possible risk factors for hematological malignancies. This meta‐analysis aims to evaluate the associations between these factors and hematological cancer risk in adults. Eligible cohort studies were sought in PubMed up to May 31, 2016; overall, 44 studies were included in the present analyses. Pooled relative risk estimates were calculated using random‐effects models; separate analyses were conducted for non‐Hodgkin lymphoma (NHL) and subtypes (diffuse large B‐cell lymphoma, DLBCL; follicular cell lymphoma; small lymphocytic lymphoma/chronic lymphocytic leukemia, SLL/CLL), Hodgkin lymphoma (HL), multiple myeloma (MM), leukemia and subtypes (acute lymphoblastic leukemia, acute myeloid leukemia, AML). Obesity was associated with increased risk of NHL, HL, MM, leukemia overall and AML in both sexes, as well as with higher DLBCL risk in women; the dose–response meta‐regression analysis confirmed these associations. Less pronounced effects were observed regarding overweight, as it was associated with increased MM risk in both sexes, NHL risk in males, DLBCL and overall leukemia risk in females. Taller men presented with significantly higher risk of NHL and taller women were affected by higher risk of NHL, DLBCL, FL, CLL/SLL, MM, leukemia and AML. On the other hand, physical activity and abdominal fatness were not associated with the risk of hematological malignancies. In conclusion, this meta‐analysis highlights the pivotal role of anthropometric measures in shaping the risk of hematological malignancies in adults. Additional, well‐designed studies stemming from all the continents are needed for the further substantiation and generalization of the results. What's new? Anthropometric measures such as body weight and height emerge as critical cancer risk factors but a comprehensive update on their effects on hematological cancers is lacking. In this meta‐analysis, the authors show that obesity increased risk across hematological malignancies in both sexes, while body height had gender‐specific more nuanced effects. They emphasize the need for further studies to disentangle the effects of abdominal obesity and physical exercise in hematological cancer risk.