Obesity, Physical Activity, and Cancer Incidence in Two Geographically Distinct Populations; The Gulf Cooperation Council Countries and the United Kingdom—A Systematic Review and Meta-Analysis

Background: The relationship between obesity, physical activity, and cancer has not been well studied across different countries. The age-standardized rate of cancer in the UK is double–triple that in the Gulf Cooperation Council Countries (GCCCs). Here, we study the association between obesity, physical activity, and cancer incidence with the aim to elucidate cancer epidemiology and risk factors in two geographically, ethnically, and climatically different parts of the world. Methods: Our systematic search (from 2016 to 2023) in PubMed, EMBASE, Scopus, and APA PsycINFO databases resulted in 64 studies totaling 13,609,578 participants. The Cochrane risk of bias tool, GRADE, R programming language, and the meta package were used. Results: Significant associations between obesity and cancer were found in both regions, with a stronger association in the UK (p ≤ 0.0001) than the GCCCs (p = 0.0042). While physical inactivity alone did not show a statistically significant association with cancer incidence, the pooled hazard ratio analysis revealed that the presence of both obesity and physical inactivity was associated with a significantly higher cancer incidence. The most common types of cancer were breast cancer in the UK and colorectal cancer across the GCCCs. Conclusion: Although both regions share similarities, advanced healthcare systems, genetic characteristics, dietary habits, and cultural practices may influence cancer incidence and types.