Abstract A88: Body mass index, height, and risk of lymphatic malignancies: A prospective cohort study
Authors: Schouten Leo , Pylypchuk Romana , Goldbohm R , Schouten Harry , van den Brandt Piet 
Published: May 2012

Abstract
A88

Introduction
Several studies have observed that body mass index (BMI) is associated with an increased risk of lymphatic malignancies (LM) or with one of its subgroups. Other studies have not observed an association, and the results are therefore inconclusive. Very few studies have investigated whether BMI around age 20 and height are associated with LM risk. We investigated therefore the association between BMI, BMI at age 20 and height and the risk of LM in a prospective cohort study.

Methods
In 1986, the Netherlands Cohort Study on Diet and Cancer (NLCS) was initiated. A self-administered questionnaire on diet and other risk factors for cancer was completed by 120,852 men and women, aged 55-69 at baseline. Data were processed and analyzed using the case-cohort approach, enumerating the cases for the entire cohort, and estimating the person years at risk in the cohort using a subcohort. This subcohort was randomly sampled from the entire cohort immediately after the baseline measurement and is being followed up for vital status. Cohort members who reported cancer at baseline were excluded from analysis. Follow-up for cancer was established by annual record linkages with the Netherlands Cancer Registry and the nationwide pathology registry. After 13.3 years of follow-up, data regarding from 1,042 LM cases and from 4,588 subcohort members were available for analysis.
Using the histology codes provided by the cancer registries and the abstracts provided by the pathology registry, the LM cases were subdivided into categories based on the third edition of the WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. There were 232 cases of diffuse large-cell lymphoma (DLCL), 79 cases of follicular lymphoma (FL), 71 cases of Waldenström macroglobulinemia/ immunocytoma (WMI), 171 cases of chronic lymphatic leukemia (CLL), and 291 cases of multiple myeloma (MM). Other subgroups were too small (N&lt;70) for analysis. Rate ratios (RRs) were estimated using the Cox proportional hazards model, with multivariate adjustment for confounders.

Results
BMI at baseline was not associated with LM risk, the RR per increment of 4 kg/m2 was 1.03 (95% confidence interval (CI): 0.94-1.13). RRs were not different between males and females. BMI at baseline was not associated with increased risk of any of the LM subtypes.
BMI around age 20 was associated with LM risk overall (RR per 4 kg/m2 increment 1.13; 95% CI: 1.01-1.25), with DLCL risk (RR 1.20; 95% CI: 0.98-1.47) and WMI risk (RR 1.41; 95% CI: 1.01-1.95). The association between BMI around age 20 and LM risk was higher in males (RR per increment of 4 kg/m2 increment: 1.22; 95% CI: 1.03-1.44) than in females (RR: 1.05; 95% CI: 0.91-1.21).
Height was positively associated with LM risk: the RR for 5 cm increment was 1.08 (95% CI: 1.02-1.15) for LM overall. The association between height and LM risk was higher in females (RR per increment of 5 cm: 1.14; 95% CI: 1.04-1.24) than in males (RR: 1.05; 95% CI: 0.89-1.13). For the DLCL subtype, the RR was 1.19 (95% CI: 1.07, 1.33).

Conclusion
The positive associations between both BMI at age 20, height and the risk of LM suggest that exposures during early life play a role in the etiology of LM.
Citation Information: Cancer Prev Res 2008;1(7 Suppl):A88.