Purpose: 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.
Methods: We estimated the univariate odds ratios (OR) and 95 % confidence intervals (CI) for breast cancer associated with plasma levels for each of 14 micronutrients.
Results: 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).
Conclusions: 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.