Increased body mass index is associated with improved survival in United States veterans with diffuse large B-cell lymphoma.
ABSTRACT PURPOSE Obesity increases the risk of death from many malignancies, including non-Hodgkin's lymphoma (NHL). In diffuse large B-cell lymphoma (DLBCL), the most common form of NHL, the association between body mass index (BMI) at diagnosis and survival is unclear. PATIENTS AND METHODS We evaluated the association between BMI at diagnosis and overall survival in a retrospective cohort of 2,534 United States veterans diagnosed with DLBCL between October 1, 1998 and December 31, 2008. Cox modeling was used to control for patient- and disease-related prognostic variables. Results Mean age at diagnosis was 68 years (range, 20 to 100 years); 64% of patients were overweight (BMI, 25 to < 30) or obese (BMI, ≥ 30). Obese patients were significantly younger, had significantly fewer B symptoms, and trended toward lower-stage disease, compared with other BMI groups. Cox analysis showed reduced mortality in overweight and obese patients (overweight: hazard ratio [HR], 0.73; 95% CI, 0.65 to 0.83; obese: HR, 0.68; 95% CI, 0.58 to 0.80), compared with normal-weight patients (BMI, 18.5 to < 25). Treatment during the rituximab era reduced the risk of death without affecting the association between BMI and survival. Disease-related weight loss occurred in 29% of patients with weight data 1 year before diagnosis. Cox analysis based on BMI 1 year before diagnosis continued to demonstrate reduced risk of death in overweight and obese patients. CONCLUSION Being overweight or obese at the time of DLBCL diagnosis is associated with improved overall survival. Understanding the mechanisms responsible for this association will require further study.