Dietary cadmium exposure and risk of epithelial ovarian cancer in a prospective cohort of Swedish women

BACKGROUND: The proposed cadmium-induced oestrogen mimicking effects in reproductive tissues, suggest a role of this widespread food contaminant in the development of hormone-dependent malignancies. METHODS: We prospectively evaluated the association between tertiles of dietary cadmium exposure and epithelial ovarian cancer in 60 889 women from the population-based Swedish Mammography Cohort. Dietary cadmium was estimated using a food-frequency questionnaire at baseline (1987-1990) and in 1997. Multivariable-adjusted rate ratios (RR) were evaluated using Cox proportional hazards models. RESULTS: During a mean follow-up of 18.9 years (1 149 470 person-years), we identified 409 incident cases of epithelial ovarian cancer, including 215 serous, 27 mucinous, 62 endometrioid and 12 clear cell tumours. We found no association between dietary cadmium exposure and the risk of ovarian cancer. Compared with the lowest tertile of cadmium exposure, the multivariable-adjusted RR for the highest tertile was 0.90 (95% confidence interval (CI): 0.71-1.15) for total epithelial ovarian cancer. Likewise, no association was observed in subtypes modelled with continuous dietary cadmium exposure; multivariable RR for each 1 mu g per day increment of cadmium: 0.97 (95% CI: 0.93-1.02) for serous tumours, 0.94 (95% CI: 0.82-1.07) for mucinous tumours and 1.00 (95% CI: 0.92-1.08) for endometrioid and clear cell tumours. CONCLUSION: Our study suggests that dietary cadmium exposure is not likely to have a substantial role in ovarian cancer development. British Journal of Cancer (2011) 105, 441-444. doi:10.1038/bjc.2011.238 www.bjcancer.com Published online 21 June 2011 (C) 2011 Cancer Research UK