Few studies have evaluated the role of micronutrients or trace elements in breast cancer development among BRCA1 mutation carriers. To investigate a possible role of dietary and environmental exposures on cancer risk, we undertook an exploratory study, using a matched case–control design (n = 48 cases and 96 controls), to evaluate the relationships between plasma levels of 14 micronutrients and breast cancer risk among BRCA1 mutation carriers in Poland.
We estimated the univariate odds ratios (OR) and 95 % confidence intervals (CI) for breast cancer associated with plasma levels for each of 14 micronutrients.
Of the 14 analytes quantified, significant differences between cases and controls were seen for two (iron and retinol; p = 0.009 and p = 0.03, respectively). Women in the highest tertile of plasma iron had a 57 % lower risk, compared with those in the lowest quartile (OR = 0.43; 95 % CI 0.18–1.04; p for trend = 0.06). Increasing antimony levels were associated with an increased risk of breast cancer (p for trend = 0.05). Women in the highest tertile had a 2.43-fold increase in breast cancer risk compared with women in the lowest tertile (OR = 2.43; 95 % CI 1.00–5.91).
This study provides some preliminary evidence regarding a role of diet, specifically iron and antimony, in the etiology of BRCA1-associated breast cancer. Prospective studies are necessary to confirm these findings.