The association between BMI and kidney cancer risk

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Objective: Obesity is considered as one of the risk factors of kidney cancer. However, the results are not consistent in reported original studies, as well as in published meta-analysis. This study aims to clarify the relationship between overweight/obesity and kidney cancer by an updated overall and dose-response meta-analysis. Methods: This meta-analysis was conducted in accordance with PRISMA guideline. Relevant studies were searched using PubMed, Embase, and Web of Science databases. The studies were limited to human cohort studies in English and Chinese language. Random-effect models and dose-response meta-analysis were used to synthesize the results. Subgroup analyses were also conducted based on the characteristics of participants. Results: Twenty-four cohort studies with 8,953,478 participants were included in our meta-analysis. Compared to the normal weight, the pooled RRs of kidney cancer was 1.35 (1.27–1.43) in overweight and 1.76 (1.61–1.91) in obese participants. An increased kidney cancer risk of 1.06 (1.05–1.06) for each 1 kg/m2 increase in BMI was showed in dose-response meta-analysis. No significant heterogeneity was found across studies with I2 = 39.4% for overweight, and I2 = 43.3% for obesity. Conclusion: The overall and dose-response meta-analysis suggested that overweight/obesity increases the risk of kidney cancer both in men and women.