Blood levels of cadmium and lead in relation to breast cancer risk in three prospective cohorts. Issue 5 (7th November 2018)

• Record Type: Journal Article
• Authors: Gaudet, Mia M.; Deubler, Emily L.; Kelly, Rachel S.; Ryan Diver, W.; Teras, Lauren R.; Hodge, James M.; Levine, Keith E.; Haines, Laura G.; Lundh, Thomas; Lenner, Per; Palli, Domenico; Vineis, Paolo; Bergdahl, Ingvar A.; Gapstur, Susan M.; Kyrtopoulos, Soterios A.
• Is Part Of: International journal of cancer. Volume 144:Issue 5(2019)
• Page Start: 1010
• Page End: 1016
• Publication Date: 2018-11-07
• Subjects: cadmium -- lead -- breast cancer; Cancer -- Periodicals; Cancer -- Prevention -- Periodicals; 616.994
• DOI: 10.1002/ijc.31805
• Languages: English
• ISSNs: 0020-7136

Abstract

Abstract : Cadmium and lead have been classified as carcinogens by the International Agency for Research on Cancer. However, their associations with breast cancer risk are unknown despite their persistence in the environment and ubiquitous human exposure. We examined associations of circulating levels of cadmium and lead with breast cancer risk 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. Metal levels were measured in stored erythrocytes from 1, 435 cases and 1, 433 controls using inductively coupled plasma‐mass spectrometry. Summary relative risks (RR) and 95% confidence intervals (CI) were calculated using random‐effects models with each study result weighted by the within‐ and between‐study variances. I 2 values were calculated to estimate proportion of between study variation. Using common cut‐points, cadmium levels were not associated with breast cancer risk in the CPS‐II cohort (continuous RR = 1.01, 95% CI 0.76–1.34), but were inversely associated with risk in the EPIC‐ Italy (continuous RR = 0.80, 95% CI 0.61–1.03) and NSHDS cohorts (continuous RR = 0.73, 95% CI 0.54–0.97). The inverse association was also evident in the meta‐analysis (continuous RR = 0.84, 95% CI 0.69–1.01) with low between‐study heterogeneity. Large differences in lead level distributions precluded a meta‐analysis of their association with breast cancer risk; no associations were found in the three studies. Adult cadmium and lead levels were not associated with higher risk of breast cancer in our large meta‐analysis. Abstract : What's new? Do cadmium and lead cause breast cancer? These two notorious toxic metals tend to linger in the body, and both are classified as carcinogens. Ubiquitous environmental contaminants, they accumulate in women particularly, due to their lower iron levels. Yet no definitive link has been demonstrated between cadmium or lead and breast cancer. Here, the authors analyzed three case–control studies. Across the three studies, a wide range of exposure levels was represented, and each study included a large number of participants. The meta‐analysis revealed no association between high levels of cadmium or lead and breast cancer risk.