Effect of Basal Metabolic Rate on Cancer: A Mendelian Randomization Study.

Basal metabolic rate is associated with cancer, but these observations are open to confounding. Limited evidence from Mendelian randomization studies exists, with inconclusive results. Moreover, whether basal metabolic rate has a similar role in cancer for men and women independent of insulin-like growth factor 1 increasing cancer risk has not been investigated. We conducted a two-sample Mendelian randomization study using summary data from the UK Biobank to estimate the causal effect of basal metabolic rate on cancer. Overall and sex-specific analysis and multiple sensitivity analyses were performed including multivariable Mendelian randomization to control for insulin-like growth factor 1. We obtained 782 genetic variants strongly (-value < 5 × 10) and independently ( < 0.01) predicting basal metabolic rate. Genetically predicted higher basal metabolic rate was associated with an increase in cancer risk overall (odds ratio, 1.06; 95% confidence interval, 1.02-1.10) with similar estimates by sex (odds ratio for men, 1.07; 95% confidence interval, 1.002-1.14; odds ratio for women, 1.06; 95% confidence interval, 0.995-1.12). Sensitivity analyses including adjustment for insulin-like growth factor 1 showed directionally consistent results. Higher basal metabolic rate might increase cancer risk. Basal metabolic rate as a potential modifiable target of cancer prevention warrants further study.