To summarise the evidence on the associations between body mass index (BMI) and BMI in early adulthood, height, waist circumference (WC) and waist-to-hip ratio (WHR), and risk of lympho-haematopoietic cancers.

We conducted a meta-analysis of prospective studies and identified relevant studies published up to December 2017 by searching PubMed. A random-effects model was used to calculate dose–response summary relative risks (RRs).

Our findings showed BMI, and BMI in early adulthood (aged 18–21 years) is associated with the risk of Hodgkin’s and non-Hodgkin’s lymphoma (HL and NHL), diffuse large beta-cell lymphoma (DLBCL), Leukaemia including acute and chronic myeloid lymphoma (AML and CML), and chronic lymphocytic leukaemia (CLL) and multiple myeloma (MM). The summary RR per 5 kg/m² increase in BMI were 1.12 [95% confidence interval (CI): 1.05–1.20] for HL, 1.05 (95% CI: 1.03–1.08) for NHL, 1.11 (95% CI: 1.05–1.16) for DLBCL, 1.06 (95% CI: 1.03–1.09) for ML, 1.09 (95% CI: 1.03–1.15) for leukaemia, 1.13 (95% CI: 1.04–1.24) for AML, 1.13 (95% CI: 1.05–1.22) for CML and 1.04 (95% CI: 1.00–1.09) for CLL, and were1.12 (95% CI: 1.05–1.19) for NHL, 1.22 (95% CI: 1.09–1.37) for DLBCL, and 1.19 (95% CI: 1.03–1.38) for FL for BMI in early adulthood analysis. Results on mortality showed a 15%, 16% and 17% increased risk of NHL, MM and leukaemia, respectively. Greater height increased the risk of NHL by 7%, DLBCL by 10%, FL by 9%, MM by 5% and Leukaemia by 7%. WHR was associated with increased risk of DLBCL by 12%. No association was found between higher WC and risk of MM.

Our results revealed that general adiposity in adulthood and early adulthood, and greater height may increase the risk of almost all types of lympho-haematopoietic cancers and this adds to a growing body of evidence linking body fatness to several types of cancers.