Background A comprehensive evaluation of the independent and combined associations of estimated glomerular filtration rate (eGFR) and albuminuria with mortality is required for assessment of the impact of kidney function on risk in the general population, with implications for improving the definition and staging of chronic kidney disease (CKD). Methods A collaborative meta-analysis of general population cohorts was undertaken to pool standardized data for all-cause and cardiovascular mortality. The two kidney measures and potential confounders from 14 studies (105,872 participants; 730,577 person-years) with urine albumin-to-creatinine ratio (ACR) measurements and seven studies (1,128,310 participants; 4,732,110 person-years) with urine protein dipstick measurements were modeled. Findings In ACR studies, mortality risk was unrelated to eGFR between 75-105 ml/min/1·73 m2 and increased at lower eGFR. Adjusted hazard ratios (HRs) for all-cause mortality at eGFR 60, 45, and 15 (versus 95) ml/min/1·73 m2 were 1·18 (95% CI: 1·05-1·32), 1·57 (1·39-1·78), and 3·14 (2·39-4·13), respectively. ACR was associated with mortality risk linearly on the log-log scale without threshold effects. Adjusted HRs for all-cause mortality at ACR 10, 30, and 300 (versus 5) mg/g were 1·20 (1·15-1·26), 1·63 (1·50-1·77), and 2·22 (1·97-2·51). eGFR and ACR were multiplicatively associated with mortality without evidence of interaction. Similar findings were observed for cardiovascular mortality and in dipstick studies. Interpretation Lower eGFR (<60 ml/min/1·73 m2) and higher albuminuria (ACR ≥10 mg/g) were independent predictors of mortality risk in the general population. This study provides quantitative data for using both kidney measures for risk evaluation and CKD definition and staging.

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BackgroundEpigenetic changes are emerging as one of the most important events in carcinogenesis. Two alterations in the pattern of DNA methylation in breast cancer (BC) have been previously reported; active estrogen receptor-α (ER-α) is associated with decreased methylation of ER-α target (ERT) genes, and polycomb group target (PCGT) genes are more likely than other genes to have promoter DNA hypermethylation in cancer. However, whether DNA methylation in normal unrelated cells is associated with BC risk and whether these imprints can be related to factors which can be modified by the environment, is unclear.Methodology/Principal FindingsUsing quantitative methylation analysis in a case-control study (n = 1,083) we found that DNA methylation of peripheral blood cell DNA provides good prediction of BC risk. We also report that invasive ductal and invasive lobular BC is characterized by two different sets of genes, the latter particular by genes involved in the differentiation of the mesenchyme (PITX2, TITF1, GDNF and MYOD1). Finally we demonstrate that only ERT genes predict ER positive BC; lack of peripheral blood cell DNA methylation of ZNF217 predicted BC independent of age and family history (odds ratio 1.49; 95% confidence interval 1.12–1.97; P = 0.006) and was associated with ER-α bioactivity in the corresponding serum.Conclusion/SignificanceThis first large-scale epigenotyping study demonstrates that DNA methylation may serve as a link between the environment and the genome. Factors that can be modulated by the environment (like estrogens) leave an imprint in the DNA of cells that are unrelated to the target organ and indicate the predisposition to develop a cancer. Further research will need to demonstrate whether DNA methylation profiles will be able to serve as a new tool to predict the risk of developing chronic diseases with sufficient accuracy to guide preventive measures.