The Association of Bisphenol A and Phthalates with Risk of Breast Cancer: A Meta-Analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 33804363 · doi:10.3390/ijerph18052375
What was done
A systematic review and meta-analysis of studies indexed in PubMed, Web of Science, and Embase up to November 2020 was conducted to examine the association between bisphenol A (BPA) and urinary phthalate metabolites and breast cancer risk. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using Stata 15.0, accompanied by sensitivity analyses.
What was found
Across 9 included studies encompassing 7,820 breast cancer cases and controls, two phthalate metabolites showed statistically significant inverse associations with breast cancer: - Mono-benzyl phthalate (MBzP): OR = 0.73 (95% CI: 0.60–0.90) - Mono-2-isobutyl phthalate (MiBP): OR = 0.75 (95% CI: 0.58–0.98) No statistically significant associations were found for BPA or the other six phthalate metabolites: - BPA: OR = 0.85 (95% CI: 0.69–1.05) - Mono-ethyl phthalate (MEP): OR = 0.96 (95% CI: 0.62–1.48) - Mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP): OR = 1.12 (95% CI: 0.88–1.42) - Mono-2-ethylhexyl phthalate (MEHP): OR = 1.13 (95% CI: 0.74–1.73) - Mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP): OR = 1.01 (95% CI: 0.74–1.40) - Mono-(3-carboxypropyl) phthalate (MCPP): OR = 0.74 (95% CI: 0.48–1.14) - Mono-butyl phthalate (MBP): OR = 0.80 (95% CI: 0.55–1.15)
Why it matters
This meta-analysis synthesizes conflicting epidemiological literature on endocrine-disrupting chemicals and finds no overall positive association between adult urinary BPA or major phthalate levels and breast cancer risk.
Limits
The total evidence base is small (9 studies), consisting primarily of correlative case-control designs prone to reverse causation and selection bias. The abstract does not specify timing of biomarker collection relative to diagnosis, adjustment for reproductive confounders, or subgroup stratification by menopausal status or breast cancer receptor subtype.
Cited by
- contradicts A meta-analysis pooling 9 case-control studies across over 7,800 participants found that specific phthalate metabolites were positively associated with breast cancer risk.