Dietary Cadmium Exposure and Risk of Breast, Endometrial, and Ovarian Cancer in the Women's Health Initiative.

Environmental health perspectives

PubMedID: 24633137

Adams SV, Quraishi SM, Shafer MM, Passarelli MN, Freney EP, Chlebowski RT, Luo J, Meliker JR, Mu L, Neuhouser ML, Newcomb PA. Dietary Cadmium Exposure and Risk of Breast, Endometrial, and Ovarian Cancer in the Women's Health Initiative. Environ Health Perspect. 2014;.
BACKGROUND
In vitro and animal data suggest cadmium, a heavy metal that contaminates some foods and tobacco plants, is an estrogenic endocrine disruptor. Elevated estrogen exposure is associated with breast, endometrial, and ovarian cancer risk.

OBJECTIVES
Examine the association between dietary cadmium intake and risk of these cancers in the large, well-characterized Women's Health Initiative (WHI).

METHODS
155,069 postmenopausal women, age 50-79, enrolled in the WHI clinical trials or observational study participated in this study. We estimated dietary cadmium consumption by combining baseline food frequency questionnaire responses with US Food and Drug Administration data on food cadmium content. Participants reported incident invasive breast, endometrial, or ovarian cancer and WHI centrally adjudicated all cases through August 2009. We applied Cox regression to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for each cancer, comparing quintiles of energy-adjusted dietary cadmium intake.

RESULTS
Over an average of 10.5 years, 6,658 invasive breast cancers, 1,198 endometrial cancers, and 735 ovarian cancers were reported. We observed no statistically significant associations between dietary cadmium and risk of any of these cancers after adjustment for potential confounders including total dietary energy intake. Results did not differ in any sub-group of women examined.

CONCLUSIONS
We found little evidence that dietary cadmium is a risk factor for breast, endometrial, or ovarian cancers in postmenopausal women. Misclassification in dietary cadmium assessment may have attenuated observed associations.