title: Urinary cadmium and mortality from all causes, cancer and cardiovascular disease in the general population: systematic review and meta-analysis of cohort studies.
abstract: Cadmium is a toxic heavy metal distributed in the environment. We conducted a systematic review and meta-analysis to examine the association between urinary cadmium concentration and mortality from all causes, cancer and cardiovascular disease (CVD) in the general population.
  
  
  
  Studies were identified by searching PubMed and Embase (to 30 March 2015) and the reference lists of retrieved articles. We included prospective studies that reported hazard ratios (HR) with 95% confidence intervals (CI) for the association between urinary cadmium concentration and all-cause, cancer or CVD mortality. A random-effects model was used to combine study-specific results.
  
  
  
  Nine cohort studies, including 5600 deaths from all causes, 1332 deaths from cancer and 1715 deaths from CVD, were eligible for inclusion in the meta-analysis. The overall HRs for the highest vs lowest category of urinary cadmium were1.44 (95% CI, 1.25-1.64; I(2 )= 40.5%) for all-cause mortality (six studies), 1.39 (95% CI, 0.96-1.99; I(2 )= 75.9%) for cancer mortality (four studies) and 1.57 (95% CI, 1.27-1.95; I(2 )= 34.0%) for CVD mortality (five studies). In an analysis restricted to six cohort studies conducted in populations with a mean urinary cadmium concentration of ≤1 µg/g creatinine, the HRs were 1.38 (95% CI, 1.17-1.63; I(2 )= 48.3%) for all-cause mortality, 1.56 (95% CI, 0.98-2.47; I(2 )= 81.0%) for cancer mortality and 1.50 (95% CI, 1.18-1.91; I(2 )= 38.2%) for CVD mortality.
  
  
  
  Even at low-level exposure, cadmium appears to be associated with increased mortality. Further large prospective studies of cadmium exposure and mortality are warranted.
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden susanna.larsson@ki.se.
authors.forename: Susanna C
authors.initials: SC
authors.lastname: Larsson
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Alicja
authors.initials: A
authors.lastname: Wolk
mesh_terms: D002104:Cadmium / Q000652:urine*; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000652:urine; D002423:Cause of Death; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D009026:Mortality; D009369:Neoplasms / Q000401:mortality* / Q000652:urine; D012307:Risk Factors
chemical_list: D002104:Cadmium
keywords: Cadmium; cancer; meta-analysis mortality; prospective studies