Associations of Maternal Urinary Cadmium with Trimester-Specific Blood Pressure in Pregnancy: Role of Dietary Intake of Micronutrients

摘要

Previous studies revealed associations of urinary Cd (U-Cd), a chronic Cd exposure biomarker, with blood pressure (BP) in non-pregnant adults. However, the evidence regarding trimester-specific blood pressure in pregnancy and U-Cd and effect modification by dietary intake of micronutrients is scarce. We randomly selected 653 women from the Omega Study cohort. U-Cd was quantified by inductively coupled plasma mass spectrometry. Trimester-specific, systolic (SBP) and diastolic blood pressure (DBP) were determined employing standard protocols and mean arterial pressure (MAP) was also calculated. Associations of SBP, DBP and MAP with U-Cd tertiles (≤0.21; 0.22–0.41; ≥0.42μg/g Cr) were assessed using multivariable linear regression models. We also explored effect modification by pre-pregnancy BMI (≤25 kg/m² or >25 kg/m²) or low/high micronutrients intake. After adjusting confounders in, women with elevated (upper tertile) as compared with those with low (lowest tertile) U-Cd (≥ 0.42 μg/g Cr vs ≤0.21 μg/g Cr, respectively) had reduced third trimester MAP (−1.8; 95% CI: −3.1, −0.5 mmHg) and second trimester MAP (−1.1; 95% CI:−2.3,−0.03 mmHg). A significant decrease in third-trimester MAP associated with increased U-Cd was observed only among normal weight women (BMI≤25 kg/m²) and women with high dietary intake of micronutrients (calcium, magnesium, zinc and selenium). Notably, U-Cd concentrations increased with the increased consumption of zinc and non-heme iron food sources. No significant differences in U-Cd concentrations were found in preeclamptic women compared with non-preeclamptic women. Our study provides evidence that dietary intake of micronutrients should be taken into account when assessing the health effects of Cd in pregnant women.