Parity and kidney cancer risk: evidence from epidemiological studies
A partir d'une revue systématique de la littérature publiée jusqu'en 2013 (6 études prospectives et 8 études cas-témoins), cette méta-analyse fait le point sur l'association entre la parité et le risque de cancer du rein
Background: Observational studies have reported conflicting results between parity and kidney cancer risk. To our knowledge, a comprehensive and quantitative assessment of the association between parity and kidney cancer has not been reported. Thus, we conducted a systematic review and dose-response meta-analysis of published epidemiological studies to summarize the evidence of this association. Methods: Relevant published studies of parity and kidney cancer were identified using MEDLINE (PubMed) database through end of June 2013. Two authors independently assessed eligibility and extracted data. Six prospective and eight case-control studies reported relative risk (RR) estimates and 95% confidence intervals (CIs) of kidney cancer associated with parity or parity number. Fixed- or random-effects models were used to estimate summary RR. Results: The summary RR of kidney cancer for the parity vs. nulliparous was 1.23 (95% CI: 1.10-1.36; Q=12.41, P=0.413, I2=3.3%). Additionally, significant association was also yielded for the highest vs. lowest parity number, with summary RR=1.36 (95% CI: 1.19-1.56; Q=8.24, P=0.766, I2=0%). In the dose-response analysis, the summary per one live birth RR was 1.08 (95% CI: 1.05-1.10; Q=9.34, P=0.500, I2=0%), also indicating positive effect of parity on kidney cancer risk. No evidence of publication bias and significant heterogeneity between subgroups were detected by meta-regression analyses. Conclusions: In summary, findings from this meta-analysis suggest that ever parity and higher parity number is significantly associated with increased risk of kidney cancer. Impact: The present results suggest a positive association between parity and kidney cancer risk.