Background
The role of basal metabolic rate (BMR) on long-term survival outcomes in cancer survivors remains inconclusive. This study prospectively investigates the dose-response association between equation‑estimated BMR and mortality using data from a nationally representative cohort.
Methods
Data from the United States (U.S.) National Health and Nutrition Examination Survey (NHANES, 2001-2018) were analyzed, and BMR was compared between cancer survivors (n = 3,434) and cancer-free adults (n = 42,425). BMR’s nonlinear association with all-cause and cause-specific mortality among survivors was assessed using multivariable Cox regression and restricted cubic spline, stratified by age and gender.
Results
The BMR of cancer survivors was significantly lower than that of participants without cancer. A total of 1,145 deaths occurred during a median follow-up of 79 months. In the overall cohort of survivors, a higher BMR was associated with reduced prevalence of all-cause and cardiac mortality, but not cancer-specific mortality. Stratified analysis showed significant associations only in those aged ≥60 years. Among older females, a U-shaped relationship was identified for all-cause mortality with an inflection point at 1546.8 kcal/d; below this threshold, higher BMR was associated with reduced mortality, while above it, risk increased. In contrast, a linear protective association was observed in older males. No significant associations were found for survivors aged <60 years.
Conclusions
Equation-estimated BMR is lower in cancer survivors and shows age- and sex-specific associations with long-term mortality, particularly in older survivors. These findings suggest that BMR may reflect underlying metabolic reserve and may provide insight into subgroup heterogeneity in survivorship, although these findings are exploratory and further validation is needed before any clinical application.