The Obesity Paradox in Survival after Cancer Diagnosis: Tools for Evaluation of Potential Bias.

ABSTRACT: The effects of overweight or obesity on survival after cancer diagnosis are difficult to discern based on observational data because these associations reflect the net impact of both causal and spurious phenomena. We describe two sources of bias that might lead to underestimation of the effect of increased body weight on survival after cancer diagnosis: collider stratification bias and heterogeneity in disease bias. Given the mixed evidence on weight status, weight change, and postdiagnosis survival for cancer patients, systematic evaluation of alternative explanations is critical. The plausible magnitudes of these sources of bias can be quantified on the basis of expert knowledge about particular cancer types using simulation tools. We illustrate each type of bias, describe the assumption

SUBMITTER: Mayeda ER 

PROVIDER: S-EPMC5858690 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature