Body size in relation to incidence of subtypes of haematological malignancy in the prospective Million Women Study

Abstract

Background: Greater adiposity and height have been associated with increased risk of haematological malignancies. Associations for disease subtypes are uncertain.

Methods: A cohort of 1.3 million middle-aged U.K. women was recruited in 1996-2001 and followed for 10 years on average. Potential risk factors were assessed by questionnaire. Death, emigration, and incident cancer were ascertained by linkage to national registers. Adjusted relative risks were estimated by Cox regression.

Results: During follow-up, 9162 participants were diagnosed with lymphatic or haematopoietic cancers. Each 10 kg m(-2) increase in body mass index was associated with relative risk of 1.20 (95% confidence interval: 1.13-1.28) for lymphoid and 1.37 (1.22-1.53) for myeloid malignancy (P=0.06 for heterogeneity); similarly, Hodgkin lymphoma 1.64 (1.21-2.21), diffuse large B-cell lymphoma 1.36 (1.17-1.58), plasma cell neoplasms 1.21 (1.06-1.39), acute myeloid leukaemia 1.47 (1.19-1.81), and myeloproliferative/myelodysplastic syndromes 1.32 (1.15-1.52). Each 10 cm increase in height was associated with relative risk of 1.21 (1.16-1.27) for lymphoid and 1.11 (1.02-1.21) for myeloid malignancy (P=0.07 for heterogeneity); similarly, mature T-cell malignancies 1.36 (1.03-1.79), diffuse large B-cell lymphoma 1.28 (1.14-1.43), follicular lymphoma 1.28 (1.13-1.44), plasma cell neoplasms 1.12 (1.01-1.24), chronic lymphocytic leukaemia/small lymphocytic lymphoma 1.23 (1.08-1.40), and acute myeloid leukaemia 1.22 (1.04-1.42). There was no significant heterogeneity between subtypes.

Conclusion: In middle-aged women, greater body mass index and height were associated with modestly increased risks of many subtypes of haematological malignancy.

Figure 1

Associations of body mass index and height with risk of haematological malignancies. Million Women Study, United Kingdom 1996–2009. Follow-up starts at recruitment. Relative risks are adjusted for alcohol intake, smoking, and socioeconomic status (and for body mass index and height where not the factor of interest) and stratified by cancer registry region. ICD-O-3, International Classification of Diseases for Oncology 3rd edition; ICD-10, International Classification of Diseases 10th revision; CLL/SLL, chronic lymphocytic leukaemia/ small lymphocytic lymphoma; Cases, number of incident cases; CI, confidence interval; P_het, result of test for heterogeneity of trends within groups. Myeloproliferative neoplasms/myelodysplastic syndromes include chronic myeloid leukaemia.