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Arsenic is associated with reduced effect of folic acid in myelomeningocele prevention: a case control study in Bangladesh.

Mazumdar M, Ibne Hasan MO, Hamid R, Valeri L, Paul L, Selhub J, Rodrigues EG, Silva F, Mia S, Mostofa MG, Quamruzzaman Q, Rahman M, Christiani DC - Environ Health (2015)

Bottom Line: Controls were selected from pregnancy registries in the same areas.Periconceptional folic acid use was ascertained by self-report, and maternal folate status was further assessed by plasma folate levels measured at the time of the study visit.Results suggest that environmental arsenic exposure reduces the effectiveness of folic acid supplementation in preventing myelomeningocele.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, USA. maitreyi.mazumdar@childrens.harvard.edu.

ABSTRACT

Background: Arsenic induces neural tube defects in several animal models, but its potential to cause neural tube defects in humans is unknown. Our objective was to investigate the associations between maternal arsenic exposure, periconceptional folic acid supplementation, and risk of posterior neural tube defect (myelomeningocele) among a highly exposed population in rural Bangladesh.

Methods: We performed a case-control study that recruited physician-confirmed cases from community health clinics served by Dhaka Community Hospital in Bangladesh, as well as local health facilities that treat children with myelomeningocele. Controls were selected from pregnancy registries in the same areas. Maternal arsenic exposure was estimated from drinking water samples taken from wells used during the first trimester of pregnancy. Periconceptional folic acid use was ascertained by self-report, and maternal folate status was further assessed by plasma folate levels measured at the time of the study visit.

Results: Fifty-seven cases of myelomeningocele were identified along with 55 controls. A significant interaction was observed between drinking water inorganic arsenic and periconceptional folic acid use. As drinking water inorganic arsenic concentrations increased from 1 to 25 μg/L, the estimated protective effect of folic acid use declined (OR 0.22 to 1.03), and was not protective at higher concentrations of arsenic. No main effect of arsenic exposure on myelomeningocele risk was identified.

Conclusions: Our study found a significant interaction between drinking water inorganic arsenic concentration from wells used during the first trimester of pregnancy and reported intake of periconceptional folic acid supplements. Results suggest that environmental arsenic exposure reduces the effectiveness of folic acid supplementation in preventing myelomeningocele.

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The predicted odds ratio of periconceptional folic acid use and myelomeningocele from the interaction model at various distributions of inorganic arsenic concentration in drinking water. Average (mean) values of parental age, child age, child sex and home birth were used to estimate odds ratios.
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Fig1: The predicted odds ratio of periconceptional folic acid use and myelomeningocele from the interaction model at various distributions of inorganic arsenic concentration in drinking water. Average (mean) values of parental age, child age, child sex and home birth were used to estimate odds ratios.

Mentions: In adjusted models, drinking water inorganic arsenic concentration collected from wells that were used during the first trimester of pregnancy was not significantly associated with risk of myelomeningocele. In models that tested the interaction between water inorganic arsenic concentrations and periconceptional folic acid use, however, the interaction was statistically significant (Table 3). Using the parameters derived from our logistic regression model, the estimated OR for periconceptional folic acid use demonstrates a decrease in the protective effect of folic acid (OR = 0.22, 95% CI [0.13, 0.37] at 1 μg/L drinking water inorganic arsenic; OR = 1.03, 95% CI [0.55, 1.91]) at 25 μg/L drinking water inorganic arsenic) (Figure 1).Table 3


Arsenic is associated with reduced effect of folic acid in myelomeningocele prevention: a case control study in Bangladesh.

Mazumdar M, Ibne Hasan MO, Hamid R, Valeri L, Paul L, Selhub J, Rodrigues EG, Silva F, Mia S, Mostofa MG, Quamruzzaman Q, Rahman M, Christiani DC - Environ Health (2015)

The predicted odds ratio of periconceptional folic acid use and myelomeningocele from the interaction model at various distributions of inorganic arsenic concentration in drinking water. Average (mean) values of parental age, child age, child sex and home birth were used to estimate odds ratios.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4404044&req=5

Fig1: The predicted odds ratio of periconceptional folic acid use and myelomeningocele from the interaction model at various distributions of inorganic arsenic concentration in drinking water. Average (mean) values of parental age, child age, child sex and home birth were used to estimate odds ratios.
Mentions: In adjusted models, drinking water inorganic arsenic concentration collected from wells that were used during the first trimester of pregnancy was not significantly associated with risk of myelomeningocele. In models that tested the interaction between water inorganic arsenic concentrations and periconceptional folic acid use, however, the interaction was statistically significant (Table 3). Using the parameters derived from our logistic regression model, the estimated OR for periconceptional folic acid use demonstrates a decrease in the protective effect of folic acid (OR = 0.22, 95% CI [0.13, 0.37] at 1 μg/L drinking water inorganic arsenic; OR = 1.03, 95% CI [0.55, 1.91]) at 25 μg/L drinking water inorganic arsenic) (Figure 1).Table 3

Bottom Line: Controls were selected from pregnancy registries in the same areas.Periconceptional folic acid use was ascertained by self-report, and maternal folate status was further assessed by plasma folate levels measured at the time of the study visit.Results suggest that environmental arsenic exposure reduces the effectiveness of folic acid supplementation in preventing myelomeningocele.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, USA. maitreyi.mazumdar@childrens.harvard.edu.

ABSTRACT

Background: Arsenic induces neural tube defects in several animal models, but its potential to cause neural tube defects in humans is unknown. Our objective was to investigate the associations between maternal arsenic exposure, periconceptional folic acid supplementation, and risk of posterior neural tube defect (myelomeningocele) among a highly exposed population in rural Bangladesh.

Methods: We performed a case-control study that recruited physician-confirmed cases from community health clinics served by Dhaka Community Hospital in Bangladesh, as well as local health facilities that treat children with myelomeningocele. Controls were selected from pregnancy registries in the same areas. Maternal arsenic exposure was estimated from drinking water samples taken from wells used during the first trimester of pregnancy. Periconceptional folic acid use was ascertained by self-report, and maternal folate status was further assessed by plasma folate levels measured at the time of the study visit.

Results: Fifty-seven cases of myelomeningocele were identified along with 55 controls. A significant interaction was observed between drinking water inorganic arsenic and periconceptional folic acid use. As drinking water inorganic arsenic concentrations increased from 1 to 25 μg/L, the estimated protective effect of folic acid use declined (OR 0.22 to 1.03), and was not protective at higher concentrations of arsenic. No main effect of arsenic exposure on myelomeningocele risk was identified.

Conclusions: Our study found a significant interaction between drinking water inorganic arsenic concentration from wells used during the first trimester of pregnancy and reported intake of periconceptional folic acid supplements. Results suggest that environmental arsenic exposure reduces the effectiveness of folic acid supplementation in preventing myelomeningocele.

Show MeSH
Related in: MedlinePlus