Journal: Blood advances
This study assessed how body mass index (BMI) at diagnosis affects outcomes in 834 patients with newly diagnosed multiple myeloma enrolled between 2009 and 2020 in the Integrative Molecular And Genetic Epidemiology study.
Using multivariable Cox models adjusted for standard prognostic factors, the investigators compared outcomes across BMI categories, using normal BMI (18.5–24.9 kg/m²) as reference. Key findings:
- All-cause mortality was higher at the BMI extremes:
- Underweight (<18.5 kg/m²): HR 1.52 (95% CI, 0.48–4.84)
- Obesity (≥30.0 kg/m²): HR 2.47 (95% CI, 1.26–4.85)
- Severe obesity (≥35 kg/m²) carried the greatest risk:
- All-cause mortality: HR 3.14 (95% CI, 1.50–6.55)
- Effect appeared particularly pronounced in:
- White patients: HR 3.22 (95% CI, 1.30–7.94)
- Female patients: HR 4.17 (95% CI, 1.20–14.47)
- However, race- and sex-specific differences were not statistically significant (P_interaction ≥ .60).
- Severe obesity was also associated with worse disease control:
- Progression or relapse: HR 1.83 (95% CI, 1.04–3.24)
- Patterns were similar when restricting to myeloma-specific mortality.
Overall, higher BMI—particularly severe obesity—at diagnosis was associated with substantially worse progression-free and overall survival in newly diagnosed myeloma, supporting weight management as a potential strategy to improve prognosis across patient groups, including Black patients.