ASPO Abstracts
Elucidating under-studied aspects of the link between obesity and multiple myeloma: a prospective assessment of the influence of the stability, trajectory, and distribution of body fatness
Category: Lifestyles Behavior, Energy Balance & Chemoprevention, Lifestyles Behavior, Energy Balance & Chemoprevention
Conference Year: 2018
Abstract Body:
Purpose: To examine the association of weight cycling, body fat distribution, and trajectory of body size across the lifespan with multiple myeloma (MM) risk. Methods: We analyzed questionnaire data from 160,865 participants in the Health Professionals Follow-up Study (HPFS) and Nurses’ Health Study (NHS). We derived weight cycling in adulthood from the question asked in 1992, “Within the last 20 years, how many times did you lose each of the following amounts of weight on purpose (excluding illness or pregnancy).” Waist circumference, hip circumferences, and waist-to-hip ratio were queried in 1986 for NHS and in 1897 for HPFS, and were updated over follow-up. Body size during childhood, adolescence, and adulthood were assessed in 1988 using 9-level “somatotype” pictograms and used to derive group-based trajectories of body size across the lifespan. We used multivariable Cox proportional hazards models to estimate cohort (sex)-specific hazard ratios (HR) and 95% confidence intervals (CI) for those obesity-related risk factors and, in final models, pooled data across both cohorts. Results: We identified a pooled total of 530 incident cases of MM during 2,868,080 person-years of follow-up. Persons with a history of extreme weight cycling, defined as a total intentional weight loss that exceeded net weight loss in those reporting one or more episodes of loss of 20 pounds, had a 75% increased risk of MM compared to individuals who stably maintained their weight (HR: 1.75; 95% CI: 1.05, 2.94). We also observed that MM risk increased significantly by 4% with each 1-inch increase in hip circumference (HR: 1.04; 95% CI: 1.00, 1.08). We identified four distinct trajectories of body size between ages five and 60 years: lean-stable, lean-increase, medium-stable, and medium-increase. Compared with individuals in the lean-stable trajectory group, those in the medium-increase trajectory category had an increased risk of MM (HR: 1.57; 95% CI: 1.17, 2.12). No other variables examined were associated with MM risk. Conclusions: Findings support the notion that maintaining a lean and stable weight throughout life will reduce the risk of MM.
Keywords: Obesity, Myeloma, Body Size, Weight Cycling