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Research: WELLS and COLLEAGUES,
Listed in Issue 253
Abstract
WELLS and COLLEAGUES, 1. School of Health Sciences, Purdue University, West Lafayette, IN, USA. wells54@purdue.edu ; 2. Columbia Center for Children's Environmental Health, Columbia University Mailman School of Public Health, New York, NY, USA; 3. National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA; 4. Center for Environmental Security, Biodesign Institute, Arizona State University, Tempe, AZ, USA; 5. Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 6. Milken Institute School of Public Health, George Washington University, Washington, DC, USA conducted a cross-sectional study assessing total mercury, speciated mercury, selenium, and n-3 polyunsaturated fatty acids in umbilical cord blood and blood pressure during labour and delivery in pregnant women
Background
Prior studies addressing associations between mercury and blood pressure have produced inconsistent findings; some of this may result from measuring total instead of speciated mercury.
Methodology
This cross-sectional study of 263 pregnant women assessed total mercury, speciated mercury, selenium, and n-3 polyunsaturated fatty acids in umbilical cord blood and blood pressure during labour and delivery. Models with a) total mercury or b) methyl and inorganic mercury were evaluated. Regression models adjusted for maternal age, race/ethnicity, prepregnancy body mass index, neighbourhood income, parity, smoking, n-3 fatty acids and selenium.
Results
Geometric mean total, methyl, and inorganic mercury concentrations were 1.40µg/L (95% confidence interval: 1.29, 1.52); 0.95µg/L (0.84, 1.07); and 0.13µg/L (0.10, 0.17), respectively. Elevated systolic BP, diastolic BP, and pulse pressure were found, respectively, in 11.4%, 6.8%, and 19.8% of mothers. In adjusted multivariable models, a one-tertile increase of methyl mercury was associated with 2.83mmHg (0.17, 5.50) higher systolic blood pressure and 2.99mmHg (0.91, 5.08) higher pulse pressure. In the same models, an increase of one tertile of inorganic mercury was associated with -1.18mmHg (-3.72, 1.35) lower systolic blood pressure and -2.51mmHg (-4.49, -0.53) lower pulse pressure. No associations were observed with diastolic pressure. There was a non-significant trend of higher total mercury with higher systolic blood pressure.
Conclusion
We observed a significant association of higher methyl mercury with higher systolic and pulse pressure, yet higher inorganic mercury was significantly associated with lower pulse pressure. These results should be confirmed with larger, longitudinal studies.
References
Wells EM1, Herbstman JB2, Lin YH3, Hibbeln JR3, Halden RU4, Witter FR5, Goldman LR6. Methyl mercury, but not inorganic mercury, associated with higher blood pressure during pregnancy. Environ Res.;154:247-252. Apr 2017. doi: 10.1016/j.envres.2017.01.013. Epub Jan 18 2017.