Obesity and renal cancer incidence and mortality--a systematic review of prospective cohort studies.

INTRODUCTION AND OBJECTIVE: There have been many studies published recently on obesity and the risk of renal cancer; however, the epidemiological evidence for such an association has not been consistent. Therefore, a systematic review was conducted of the prospective cohort studies to assess the association between obesity and the risk of renal cancer incidence and death. MATERIALS AND METHODS: A search was conducted of the PubMed database and references to published studies from inception until May 2013. Guidelines for Assessing Quality in Prognostic Studies on the Basis of Framework for Potential Biases were followed for quality assessment of studies included in the systematic review. RESULTS: Twenty eligible studies were identified and included in the systematic review. Among the 20 selected studies, overall study quality was high. Although the evidence from the prospective cohort studies, linking obesity with renal cancer incidence, has not been entirely consistent, there is a convincing body of data for a positive relationship. Moreover, cumulative data is compelling for a strong positive association between obesity and fatal renal cancer. CONCLUSIONS: There is a relatively consistent amount of evidence that obesity increases the risk of renal cancer and fatal renal cancer. Further research is needed as better understanding of mechanisms by which obesity may influence renal cancer development and progression will aid the fostering of strategies for prevention and treatment of one of the most lethal human malignancies.