Gaudet MM, et al. - In three case-control studies nested within the Cancer Prevention Study-II (CPS-II) LifeLink Cohort, European Prospective Investigation into Cancer and Nutrition – Italy (EPIC-Italy) and the Northern Sweden Health and Disease Study (NSHDS) cohorts, researchers assessed breast cancer risk in relation to circulating levels of cadmium and lead. They used random-effects models to calculate summary relative risks (RR) and 95% confidence intervals (CI), with each study result weighted by the within- and between-study variances. Proportion of between study variation was estimated by calculating I² values. Findings of this large meta-analysis revealed no association of adult cadmium and lead levels with higher risk of breast cancer.