Exposure to perchlorate and cardiovascular disease in China: A community-based cross-sectional study and benchmark dose estimation.

The association between exposure to perchlorate, which inhibits thyroidal iodine uptake, and cardiovascular disease (CVD) is unclear in China. Moreover, the point of departure (POD) for perchlorate based on observed adverse health effect in Chinese populations remains absent. A total of 2355 adults (mean age 50.4 years and 39.2% male) from four communities in Shenzhen were included in analyses. Spot urine specimens were collected to measure urinary perchlorate concentrations, which were applied to estimate daily intakes of perchlorate. Multivariable logistic regression model was applied to examine the association between perchlorate and CVD. The roles of cardiometabolic risk factors, including obesity, abdominal obesity, hypertension, diabetes, and hyperlipidemia, were evaluated with mediation analyses. We further employed Bayesian benchmark dose (BMD) modeling to derive the POD for risk assessment. Comparing extreme tertiles, subjects in the highest perchlorate tertile had a significantly elevated risk of prevalent CVD (OR: 2.16; 95% CI: 1.28, 3.65). Multivariable-adjusted ORs for hypertension, diabetes, and hyperlipidemia associated with per doubling in urinary perchlorate concentration were 1.11 (95% CI: 1.01, 1.21), 1.15 (95% CI: 1.02, 1.28), and 1.11 (95% CI: 1.01, 1.20), respectively. Hypertension, diabetes, and hyperlipidemia partially mediated the perchlorate-CVD association (mediated proportion ranged from 7.75% to 11.30%). Given a benchmark response of 5% and 10%, the model-averaged BMD lower bounds (BMDLs) of perchlorate exposure on CVD were 0.15 and 0.40 μg/kg-bw day, respectively. Our estimated POD for perchlorate was lower than those recommended by other groups. These findings call for stricter regulations on perchlorate contamination to promote cardiovascular health in China.