Multiple myeloma is a rare but highly fatal hematologic malignancy. Excess weight may be associated with this cancer, but several unresolved questions remain regarding timing and location of body weight in relation to multiple myeloma risk. To better understand these relationships, we conducted a pooled analysis of multiple myeloma mortality using 1.5 million participants from 20 prospective cohorts in the National Cancer Institute Cohort Consortium. Among cohort participants, the median baseline body mass index (BMI) was 25.6 and 21.0 kg/m2 at cohort entry and early adulthood, respectively, and the median waist circumference at cohort entry was 88 cm. During follow-up (10 years on average), we documented 1,388 multiple myeloma deaths. Using proportional hazards regression we calculated pooled hazard ratios (HRs) and 95% confidence intervals (CIs) overall and by sex. We observed associations with elevated multiple myeloma mortality for higher BMI at cohort entry (HR 1.09, 95% CI: 1.03-1.16 per 5kg/m2), early-adult BMI (HR=1.12, 95% CI: 0.97-1.30 per 5kg/m2), and waist circumference at cohort entry (HR= 1.06, 95% CI: 1.02-1.10 per 5cm) for men and women combined. These results were slightly stronger for women but the differences were not statistically significant. Mutual adjustment for each of the body size measures yielded similar results. Individuals who were the heaviest both in early adulthood (BMI 25+) and at cohort entry (BMI 30+) had the greatest risk of myeloma mortality compared to those with BMI 18.5-<25 at both time points (HR=1.71, 95% CI: 1.18-2.49). Waist-to-hip ratio and height were not significantly associated with multiple myeloma mortality. These observations suggest that both overall and central obesity play a role in myeloma mortality, and that maintaining a higher body weight throughout adulthood confers the highest risk of death from this cancer.

This abstract is also presented as Poster B47.

Citation Format: Lauren R. Teras, Cari M. Kitahara, Brenda M. Birmann, Patricia A. Hartge, Sophia S. Wang, Alpa V. Patel, Kim Robien, Hans-Olov Adami, Elisabete Weiderpass, Graham G. Giles, Susan M. Gapstur, Amy Berrington de González, Mark Purdue, on behalf of the Cohort Consortium Pooling Project on BMI and Mortality. Body size and multiple myeloma mortality: A pooled analysis of 20 prospective studies. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr PR07.

©2013 American Association for Cancer Research.
2013