Blood Pressure in Relation to Biomarkers of Lead, Cadmium, Copper, Zinc, and Selenium in Men without Occupational Exposure to Metals

Abstract

The interrelationship of blood lead (BPb), activity of δ-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), blood cadmium (BCd), serum copper (SCu), serum zinc (SZn), serum selenium (SSe), hematocrit (Hct), body mass index (BMI), age, smoking habits, and alcohol consumption to blood pressure was examined in 154 Croatian male subjects 19–53 years of age. None of the subjects had been occupationally exposed to metals, or used any medication that could influence blood pressure or metal metabolism. The median and range values were: BPb, 57 (25–254) μg/L; ALAD, 51.9 (22.8–96.4) European units; EP, 0.68 (0.38–1.68) μmol/L erythrocytes; BCd, 0.83 (0.21–11.93) μg/L; SCu, 1113 (763–1662) μg/L; SZn, 961 (734–1213) μg/L; SSe, 73.6 (44.2–106.9) μg/L; systolic blood pressure, 131 (105–165) mm Hg; and diastolic blood pressure, 94 (71–112) mm Hg. Systolic and diastolic blood pressure significantly correlated with an increase in BMI (P<0.0005 and P<0.0001, respectively), EP (P<0.0002 and P<0.002, respectively), and BPb (P<0.005 and P<0.01, respectively). After adjusting for potential confounding variables by multiple regression, an increase in systolic blood pressure was significantly predictive by BMI (P<0.0005) and log BPb (P<0.02) and inversely by log BPb*SSe interaction term (P<0.007), or alternatively by EP (P<0.0001), BMI (P<0.001), alcohol (P<0.02), and Hct (P<0.05). An increase in diastolic blood pressure was significantly predictive by BMI (P<10−5), log BPb (P<0.04), and alcohol (P=0.05) and inversely by log BPb*SSe interaction term (P<0.0007), or alternatively by BMI (P<0.0001), EP (P<0.002), alcohol (P<0.004), and Hct (P<0.04) and inversely by smoking (P<0.04). With respect to the EP range in the study population, an increase of 27 mm Hg in systolic and 14 mm Hg in diastolic blood pressure was found. The study results indicate a significant Pb-related increase in blood pressure, particularly within the low-level Pb exposure range (BPb of 25–75 μg/L, and/or EP of 0.4–1.0 μmol/L erythrocytes).