title: Dietary cadmium intake and breast cancer risk in Japanese women: a case-control study.
abstract: Cadmium, an environmental pollutant, may act like an estrogen and be a potential risk factor for estrogen-dependent diseases such as breast cancer. We examined the hypothesis that higher dietary cadmium intake is associated with risk of overall and hormone receptor-defined breast cancer in Japanese women, a population with a relatively high cadmium intake. The study was conducted under a case-control design in 405 eligible matched pairs from May 2001 to September 2005 at four hospitals in Nagano Prefecture, Japan. Dietary cadmium intake was estimated using a food frequency questionnaire. Multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer and its hormone-receptor-defined subtypes were calculated by tertile of dietary cadmium intake. We found no significant association between dietary cadmium and risk of total breast cancer in either crude or multivariable-adjusted analysis. Adjusted ORs for tertiles of cadmium intake were 1.00, 1.19, and 1.23 (95% CI, 0.76-2.00; P for trend=0.39) for whole breast cancer. Further, no significant associations were seen across strata of menopausal status, smoking, and diabetes in multivariable-adjusted models except for adjusted OR for continuous cadmium intake in postmenopausal women. A statistically significant association was found for estrogen receptor-positive (ER+) tumors among postmenopausal women (adjusted OR=1.00, 1.16, and 1.94 [95% CI, 1.04-3.63; P for trend=0.032]). Although the present study found no overall association between dietary cadmium intake and breast cancer risk, higher cadmium intake was associated with increased risk of ER+ breast cancer in postmenopausal women, at least at regular intake levels in Japanese women in the general population. Further studies are needed to confirm this association.
authors.affiliation: Department of Epidemiology and Environmental Health, Juntendo University Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Itoh
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Norie
authors.initials: N
authors.lastname: Sawada
authors.forename: Ribeka
authors.initials: R
authors.lastname: Takachi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kasuga
authors.forename: Shiro
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Onuma
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishimura
authors.forename: Ritsu
authors.initials: R
authors.lastname: Kusama
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Yokoyama
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology*; D002104:Cadmium / Q000032:analysis*; D016022:Case-Control Studies; D004032:Diet; D004785:Environmental Pollutants / Q000032:analysis*; D005260:Female; D005506:Food Contamination; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D016017:Odds Ratio; D012306:Risk
chemical_list: D004785:Environmental Pollutants; D002104:Cadmium
keywords: Endocrine disrupter; Epidemiology; Estrogen-mimicking; Heavy metal; Hormone receptor