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Dietary cadmium and risk of breast cancer subtypes defined by hormone receptor status: A prospective cohort study
Author(s) -
Grioni Sara,
Agnoli Claudia,
Krogh Vittorio,
Pala Valeria,
Rinaldi Sabina,
Vinceti Marco,
Contiero Paolo,
Vescovi Luciano,
Malavolti Marcella,
Sieri Sabina
Publication year - 2019
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.32039
Subject(s) - breast cancer , medicine , prospective cohort study , hazard ratio , confounding , estrogen receptor , cadmium , cancer , risk factor , cohort study , gynecology , cohort , physiology , oncology , confidence interval , endocrinology , chemistry , organic chemistry
Diet is the primary source of cadmium—a proven Group 1 human carcinogen—for non‐smokers. Observational studies investigating the effect of cadmium from food sources on breast cancer risk have produced inconsistent results. We examined the association between dietary cadmium and risk of breast cancer defined by estrogen receptor (ER), progesterone receptor (PR) and HER2 status, in 8924 women recruited to a prospective study between 1987 and 1992. Dietary cadmium intake was estimated using a semi‐quantitative food frequency questionnaire at baseline. During a median of 22 years of follow‐up, 451 incident cases of breast cancer were identified through the Varese Cancer Registry. Multivariable‐adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for breast cancer and receptor‐defined breast cancer subtypes were estimated for quintiles of dietary cadmium intake, adjusting for confounding factors. Mean dietary cadmium intake was 7.8 (standard deviation 1.4) μg/day. Women with highest quintile of cadmium intake had a greater risk of breast cancer (HR 1.54; 95% CI, 1.06–2.22; p trend = 0.028) than those with lowest quintile of intake. Women premenopausal at recruitment had HR = 1.73 (95% CI, 1.10–2.71, highest vs . lowest quintile); postmenopausal women had HR = 1.32 (95% CI, 1.05–1.66 for each standard deviation increase in cadmium). Cadmium‐related risk of breast cancer did not vary with ER, PR or HER2 status (p‐heterogeneity not significant). These findings support the hypothesis that dietary cadmium is a risk factor for breast cancer.