Journal of Exposure Science and Environmental Epidemiology advance online publication 6 January 2016; doi: 10.1038/jes.2015.86
- 1Department of Obstetrics and Gynecology, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- 2Population Studies Division, Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, Environmental Health Center, Ottawa, Ontario, Canada
- 3Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
Correspondence:
Dr Cynthia K Colapinto, Department of Obstetrics and Gynecology,
Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada
J1H 5N4. E-mail: cynthia.colapinto@gmail.com
Received 27 July 2015; Revised 5 October 2015; Accepted 13 October 2015
Advance online publication 6 January 2016
Advance online publication 6 January 2016
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Abstract
The
aim of this analysis was to examine the association between tea intake
during pregnancy and maternal and infant metal exposures. Data from the
Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a
pan-Canadian pregnancy cohort, were used. All participants with a
gestational age of 
20 weeks (n=1954)
with available biomarkers were included. Geometric means (GMs) for
lead, arsenic, mercury, cadmium and manganese in maternal (first and
third trimesters) and cord blood, as well as speciated arsenic in
maternal urine in the first trimester, were calculated for participants
who drank regular, green or herbal tea and for those who did not.
Differences between groups were examined using chi-square tests.
Adjusted least squares geometric means (LSGMs) were estimated by tea
intake, controlling for factors such as country of birth, coffee intake
and maternal smoking. Concentrations of all metals were above the limits
of detection in most participants in the first trimester: lead (GM):
0.62 μg/dl), mercury (GM: 2.99 nmol/l); cadmium (GM 1.93 nmol/l), arsenic (GM 9.75 nmol/l) and manganese (GM 160.1 nmol/l).
Adjusted LSGMs for lead in the first trimester were higher for tea
drinkers than for those who were non-tea drinkers (LSGM 0.65 μg/dl, 95%CI: 0.62, 0.69 and 0.61 μg/dl, 95%CI:
0.59, 0.62), and there was evidence of a dose–response relationship for
green and herbal tea. Those who consumed herbal tea in the third
trimester had significantly higher third trimester maternal and cord
blood lead concentrations than non-herbal tea drinkers. This study
provides evidence of an association between blood lead concentrations
and green or herbal tea consumption. However, the GM blood lead
concentrations of the highest tea consumers were still less than 1 μg/dl and within the normal range of blood lead concentrations in the Canadian population.
20 weeks (n=1954)
with available biomarkers were included. Geometric means (GMs) for
lead, arsenic, mercury, cadmium and manganese in maternal (first and
third trimesters) and cord blood, as well as speciated arsenic in
maternal urine in the first trimester, were calculated for participants
who drank regular, green or herbal tea and for those who did not.
Differences between groups were examined using chi-square tests.
Adjusted least squares geometric means (LSGMs) were estimated by tea
intake, controlling for factors such as country of birth, coffee intake
and maternal smoking. Concentrations of all metals were above the limits
of detection in most participants in the first trimester: lead (GM):
0.62 μg/dl), mercury (GM: 2.99 nmol/l); cadmium (GM 1.93 nmol/l), arsenic (GM 9.75 nmol/l) and manganese (GM 160.1 nmol/l).
Adjusted LSGMs for lead in the first trimester were higher for tea
drinkers than for those who were non-tea drinkers (LSGM 0.65 μg/dl, 95%CI: 0.62, 0.69 and 0.61 μg/dl, 95%CI:
0.59, 0.62), and there was evidence of a dose–response relationship for
green and herbal tea. Those who consumed herbal tea in the third
trimester had significantly higher third trimester maternal and cord
blood lead concentrations than non-herbal tea drinkers. This study
provides evidence of an association between blood lead concentrations
and green or herbal tea consumption. However, the GM blood lead
concentrations of the highest tea consumers were still less than 1 μg/dl and within the normal range of blood lead concentrations in the Canadian population.Keywords:
lead; metals; MIREC; tea
