Chronic Cadmium Exposure and Genetic Polymorphisms of MMP-2 and MMP-9 in a Population Exposed to Steel Slag in the State of Rio de Janeiro, Brazil: A Cross-Sectional Study

Genetic polymorphisms in the matrix metalloproteinases (MMPs) family genes may be associated with cadmium (Cd) levels and its adverse effects. This study investigated the impact of MMP-2 and MMP-9 polymorphisms on Cd levels in 238 residents of a condominium in Rio de Janeiro, Brazil, built over an industrial steel slag waste. Polymorphisms were genotyped using TaqMan validated assays, and the Cd levels were measured in blood (BCd) and urine (UCd) samples by atomic absorption spectrometry. Associations were evaluated by linear correlation coefficients and multiple logistic regression, using odds ratios (OR) and 95% confidence intervals (CI). Mean age was 50 ± 15 years; 58% were female, 69% non-smokers. Mean concentrations for BCd and UCd were 0.70 ± 0.2 μg L(−1) and 0.56 ± 0.55 μg L(−1), respectively. Smoking status was associated with BCd ≥ 0.70 μg L(−1) (OR = 2.9; 95% CI = 1.6–5.9). MMP-9 rs17576 A > G was associated with BCd ≥ 0.70 μg L(−1) (OR = 2.11; 95% CI = 1.10–4.05) and UCd ≥ 0.56 μg L(−1) (OR = 3.38; 95% CI = 1.82–7.65). Knowing possible individual predisposing factors is essential to understand Cd toxicity, and to improve the monitoring of high-risk populations.