RESUMO
Background Occupational exposure to lead, cadmium, or arsenic is a potential risk factor for blood pressure elevation. Current studies mainly focus on the relationship between a single metal and blood pressure. However, mixed metal exposure often exists in the actual working environment, and the interactive effects of polymetallic interactions on blood pressure and the dose-effect relationship remain unclear yet. Objective To explore the influence proportion of occupational exposure to lead, cadmium, or arsenic on blood pressure and their interactive effects. Methods From January to December 2021, workers from a smelter in southern China were selected. Demographic characteristics, height, weight, and blood pressure of workers were collected through questionnaire and physical examination. At the same time, their urine samples were collected and the levels of urinary lead, urinary cadmium, and urinary arsenic were detected by inductively coupled plasma mass spectrometry, and corrected by urinary creatinine (Cr). Linear regression and logistic regression were used to analyze the relationship between urinary lead, cadmium, and arsenic and blood pressure. Weighted quantile sum (WQS) regression was applied to evaluate the dose-effect relationship between urinary lead, cadmium, and arsenic exposures and blood pressure and the effect weight of each metal on blood pressure. Generalized linear regression and additive/multiplicative scaling were used to identify interactive effects of the three metals on blood pressure. Results A total of 1075 workers were included in this study, with a mean age of (44.68±5.11) years and mean working seniority of (24.66±5.23) years. There were 891 males (88.9%) and 184 were females (17.1%); 24.7% workers were drinkers and 45.7% workers were smokers; 302 workers (28.1%) reported hypertension and 37 of them were taking antihypertensive drugs. The P50 (P25, P75) levels of urinary lead, urinary cadmium, and urinary arsenic were 6.11 (3.71, 11.08), 3.88 (2.68, 5.44), and 26.04 (19.99, 35.11) μg·g−1, respectively. After adjusting for gender, age, working seniority, body mass index, smoking, drinking, and the usage of antihypertensive drugs, systolic and diastolic blood pressure increased by 0.772 and 0.418 mmHg respectively for 10% increase in lead, cadmium, and arsenic mixed exposure. Urinary cadmium, among the three single exposures, had the greatest effect on systolic and diastolic blood pressure, weight (w)=0.523 and 0.551 respectively. The interaction of urinary lead and urinary cadmium was positively correlated with the occurrence of hypertension, multiplicative interaction OR (ORint)=1.88 (95%CI: 1.09, 3.63), attributable proportion due to interaction (AP)=1.19 (95%CI: 0.40, 8.18). Conclusion This study shows that mixed exposure to lead, cadmium, and arsenic has a positive relationship with blood pressure, in which cadmium plays a major role. Co-exposure to lead and cadmium has a positive interactive effect on hypertension development and systolic blood pressure elevation.
RESUMO
Background Exposure to environmental lead can cause kidney damage and telomere wear. However, the relationship among lead, peripheral blood telomere length, and glomerular filtration rate (eGFR) are unclear. Objective This study is conducted to investigate the relationships of urinary lead level with peripheral blood telomere length and renal function index eGFR, and further explore whether peripheral blood telomere length plays an intermediary role in the relationship between urinary lead level and eGFR. Methods A case-control study was conducted to select 497 residents from two communities in a city, including 230 in the control group (eGFR≥80 mL·min−1) and 267 in the abnormal eGFR group (eGFR<80 mL·min−1). Basic information and health information of the subjects were collected through a face-to-face questionnaire survey. Fasting morning urine was collected, and urinary lead and urinary creatinine (UCr) were detected. Fasting peripheral venous blood was collected to detect telomere length and serum creatinine (SCr) in peripheral blood leukocytes. eGFR was estimated by the Levey formula. After further adjusting for age, gender, education level, family per capita monthly income, smoking, and drinking the relationship among urinary lead level, peripheral blood telomere length, and renal function index eGFR was evaluated by mediating effect analysis. Results The overall level of creatinine-adjusted urinary lead [M (P25, P75)] in the abnormal eGFR group was 3.85 (1.56, 7.34) μg·g−1 which was higher than that in the control group, 1.57 (0.60, 3.62) μg·g−1(P<0.001). In addition, the overall level of peripheral blood telomere length in the abnormal eGFR group was 2.42 (1.89, 3.10) Kb, lower than that in the control group, 2.69 (2.09, 3.64) Kb (P<0.001). The results of mediating effect analysis showed that the magnitude of mediating effect by peripheral blood telomere length was −0.276 (95%CI: −0.708-−0.001) and it contributed 3.35% to the relationship between urinary lead level and eGFR. In women, the magnitude of mediating effect by peripheral blood telomere length was −0.484 (95%CI: −1.160-−0.023) between urinary lead level and eGFR, and the proportion of the mediating effect was 5.34%. In men, no mediating role of peripheral blood telomere length was found between urinary lead and eGFR. Conclusion Urinary lead level is closely related to renal function index eGFR and telomere length in peripheral blood. Peripheral blood telomere length plays a mediating role in the relationship between female urinary lead and eGFR in women.