Association of blood and hair mercury with blood pressure and vascular reactivity.

BACKGROUND Some studies suggest that high levels of blood and hair mercury (Hg) increase the risk of atherothrombotic diseases, an effect that may be explained by oxidative damage to the vascular endothelium. OBJECTIVES We tested whether high Hg levels impair the vasodilating function of the vascular endothelium or increase blood pressure. METHODS We measured the association between high blood and hair Hg and brachial artery flow mediated vasodilation (FMD%), middle cerebral artery reactivity to CO2 (MCAR%) and hypertensive status in 101 participants in the Wisconsin Sleep Cohort Study (mean age of 59.4 years; 52.5% male). Whole blood total Hg and hair total Hg were tested using inductively coupled plasma mass spectrometry and cold vapor atomic fluorescence spectrometry, respectively. RESULTS Geometric mean blood and hair Hg were 1.16 microg/L and 270.1 ng/g. Blood and hair Hg were not significantly associated with FMD% and MCAR%. However, after adjustment for other risk factors, people in the upper quartile of blood Hg were 1.9 times (P=0.23) more likely to be hypertensive and those in the upper quartile of hair Hg were more than 4 times more likely (P=0.02). CONCLUSION High hair and blood Hg levels do not seem to influence vascular reactivity, but may increase the risk of hypertension.