Impact of obesity on gastroenterological diseases: a protocol for umbrella review of systematic review and meta-analysis

ABSTRACT The global prevalence of overweight and obesity among both men and women has risen as the global mean BMI has increased[1, 2]. As digestive diseases were known to have a close relation to metabolic and mechanical changes in obesity cohorts[3], several previous meta-analyses reported the association between obesity and gastroenterological diseases including cancers[4-9] and benign diseases[10-15] of the digestive system. Although some of the reported association between obesity and gastroenterological diseases might be causal, considerable heterogeneity, confounders, and bias could be included in the studies. We aim to conduct an umbrella review to evaluate the validity and strength of existing evidence for the impact of obesity on the risk and outcomes of gastroenterological (GI) diseases.