000			03729nam a22002897a 4500
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028			_bPhone: +255 28 298 3384
028			_b Fax: +255 28 298 3386
028			_b Email: vc@bugando.ac.tz
028			_b Website: www.bugando.ac.tz
040			_cdlc
041			_aEnglish _dEnglish _eEnglish _gEnglish _hEnglish
100			_aFrancois P. Bernier _944190
245			_aMaternal exposure to arsenic and mercury and associated risk of adverse birth outcomes in small-scale gold mining communities in Northern Tanzania
260			_aMwanza, Tanzania: _b Elsevier & _b Catholic University of Health and Allied Sciences [CUHAS – Bugando] _cApril 2020
490			_v Environment International Volume 137 Issue 105450
520			_aAbstract Background Exposure to arsenic and mercury in artisanal and small-scale gold mining (ASGM) communities is an issue that predominantly affects low and middle-income countries. Large epidemiology studies in these communities are rare, and the impact of such exposures on reproductive outcomes are not well understood. Objective To examine associations between prenatal maternal arsenic and mercury exposure and birth outcomes in both ASGM and non-ASGM communities in Northern Tanzania. Methods This longitudinal prospective study included 961 women (ASGM = 788, non-ASGM = 173) of the original cohort of 1056 who were followed until a pregnancy outcome was registered. Maternal spot urine samples and dried blood spots were used to measure total arsenic (T-As) and total mercury (T-Hg) in the second trimester of pregnancy. Data on adverse birth outcomes were collected in 5 categories: spontaneous abortion, stillbirth, preterm birth, low birth weight, and visible congenital anomalies. Mann-Whitney U-tests were used to test for differences between median T-As and T-Hg by area of residence. Logistic regression models were used to estimate the odds of stillbirth and visible congenital anomalies given maternal T-As and T-Hg levels. Modified Poisson regressions were used to estimate relative risk ratios between maternal T-As and T-Hg levels and composite adverse birth outcome, spontaneous abortion, low birth weight, and preterm birth. Results Statistically significant differences were found in median T-As (9.6 vs. 6.3 µg/L, Mann-Whitney U-tests, Z = −3.50, p < 0.001) and median T-Hg blood concentrations (1.2 vs. 0.70 µg/L, Z = −9.88, p-value < 0.001) between women living in ASGM and non-ASGM areas respectively. In ASGM areas, the adjusted relative risk (aRR) of a composite adverse birth outcome increased with increasing T-As (aRR 1.23, 95%CI: 1.14–1.33, p < 0.0001) and T-Hg (aRR 1.17, 95%CI: 1.1–1.25, p < 0.0001) exposure. Spontaneous abortion (aRR 1.53, 95%CI: 1.28–1.83), stillbirth (adjusted odds ratio (aOR) 1.97, 95%CI: 1.45–2.66) and preterm birth (1.17, 95%CI: 1.01–1.36) were significantly associated with elevated T-As, whereas elevated T-Hg was significantly associated with stillbirth (aOR 2.49, 95%CI: 1.88–3.29) and visible congenital anomalies (aOR 2.24, 95%CI: 1.3–3.87). Conclusion Over half (54.7%) of women in ASGM areas of Northern Tanzania had adverse birth outcomes and the risk of adverse birth outcomes was significantly associated with increased prenatal exposure to arsenic and mercury.
700			_aElias C. Nyanza _919632
700			_aDeborah Dewey _922805
700			_aMange Manyama _920085
700			_a Jonathan W. Martin _944191
700			_a Jennifer Hatfield _923044
856			_uhttps://doi.org/10.1016/j.envint.2019.105450 _yhttps://doi.org/10.1016/j.envint.2019.105450
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999			_c19040 _d19040