Poster: Cadmium exposure and risk of breast cancer: a meta-analysis
- Details
- Published on Monday, 02 November 2015 10:00
Background and aims
Cadmium (Cd) is a toxic metal with estrogenic activity and established human carcinogenicity, but several uncertainties still exist about the amounts of relevant exposure and particularly the cancer types involved.
Methods
We carried out a systematic search in the PubMed-Medline database in April 2015, using as MeSH terms 'cadmium', 'breast cancer', or 'breast tumor'. We identified 24 eligible studies, 16 case-control and 8 cohort ones. We performed a meta-analysis according to study design and type of Cd exposure assessment, using random-effects model considering the moderate heterogeneity between these investigations.
Results
The exposure assessment methodology influenced the meta‐analysis results, which however generally indicated an increased risk of breast cancer. For studies using urine Cd concentrations for exposure assessment, we found a summary relative risk (RR) of 2.14 (95% CI 1.37-3.34) and 1.39 (0.67-2.92) for case-control and cohort studies, respectively.
For cohort studies using dietary Cd intake for exposure assessment, summary RR was 1.00 (0.87-1.15). Stratified analysis according to Estrogen Receptor (ER) status showed a summary RRs of 1.05 (0.94-1.16) and 1.00 (0.82-1.21) for positive and negative cancer types, respectively. For Progesterone Receptor (PR), RRs were 0.87 (0.69-1.10) and 1.10 (0.83-1.45) for positive and negative status, respectively. Considering body mass index (BMI) as effect modifier, RR was 1.08 (0.96-1.23) and 0.99 (0.93-1.05) for BMI<25 and BMI≥25, respectively.
Conclusions
Despite the limitations of this meta‐analysis, such as the differences in exposure assessment methods and the statistical imprecision of the point estimates, overall results appear to suggest a direct association between cadmium exposure and breast cancer, with higher RR in subgroups such as ER-positive, PR-negative and normal weight women.
