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Prenatal mercury exposure, maternal seafood consumption and associations with child language at five years

Vejrup, Kristine; Brandlistuen, Ragnhild Eek; Brantsæter, Anne Lise; Knutsen, Helle Katrine; Caspersen, Ida Henriette; Alexander, Jan; Lundh, Thomas LU ; Meltzer, Helle Margrete; Magnus, Per and Haugen, Margaretha (2018) In Environment International 110. p.71-79
Abstract

Background: Methyl mercury (MeHg) is a well-known neurotoxin and evidence suggests that also low level exposure may affect prenatal neurodevelopment. Uncertainty exists as to whether the maternal MeHg burden in Norway might affect child neurodevelopment. Objective: To evaluate the association between prenatal mercury exposure, maternal seafood consumption and child language and communication skills at age five. Methods: The study sample comprised 38,581 mother-child pairs in the Norwegian Mother and Child Cohort Study. Maternal mercury blood concentration in gestational week 17 was analysed in a sub-sample of 2239 women. Prenatal mercury exposure from maternal diet was calculated from a validated FFQ answered in mid-pregnancy. Mothers... (More)

Background: Methyl mercury (MeHg) is a well-known neurotoxin and evidence suggests that also low level exposure may affect prenatal neurodevelopment. Uncertainty exists as to whether the maternal MeHg burden in Norway might affect child neurodevelopment. Objective: To evaluate the association between prenatal mercury exposure, maternal seafood consumption and child language and communication skills at age five. Methods: The study sample comprised 38,581 mother-child pairs in the Norwegian Mother and Child Cohort Study. Maternal mercury blood concentration in gestational week 17 was analysed in a sub-sample of 2239 women. Prenatal mercury exposure from maternal diet was calculated from a validated FFQ answered in mid-pregnancy. Mothers reported children's language and communications skills at age five by a questionnaire including questions from the Ages and Stages Questionnaire (ASQ), the Speech and Language Assessment Scale (SLAS) and the Twenty Statements about Language-Related Difficulties (language 20). We performed linear regression analyses adjusting for maternal characteristics, nutritional status and socioeconomic factors. Results: Median maternal blood mercury concentration was 1.03. μg/L, dietary mercury exposure was 0.15. μg/kg. bw/wk, and seafood intake was 217. g/wk. Blood mercury concentrations were not associated with any language and communication scales. Increased dietary mercury exposure was significantly associated with improved SLAS scores when mothers had a seafood intake below 400. g/wk in the adjusted analysis. Sibling matched analysis showed a small significant adverse association between those above the 90th percentile dietary mercury exposure and the SLAS scores. Maternal seafood intake during pregnancy was positively associated with the language and communication scales. Conclusion: Low levels of prenatal mercury exposure were positively associated with language and communication skills at five years. However, the matched sibling analyses suggested an adverse association between mercury and child language skills in the highest exposure group. This indicates that prenatal low level mercury exposure still needs our attention.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Diet, Fish and seafood intake, Language development, Maternal blood levels, Methylmercury, The Norwegian mother and child cohort study
in
Environment International
volume
110
pages
71 - 79
publisher
Elsevier
external identifiers
  • scopus:85032370484
  • wos:000414872800008
ISSN
0160-4120
DOI
10.1016/j.envint.2017.10.008
language
English
LU publication?
yes
id
9fd289c1-e6fe-44c0-93f3-51f40e062c5d
date added to LUP
2017-11-08 12:28:58
date last changed
2018-02-08 03:00:02
@article{9fd289c1-e6fe-44c0-93f3-51f40e062c5d,
  abstract     = {<p>Background: Methyl mercury (MeHg) is a well-known neurotoxin and evidence suggests that also low level exposure may affect prenatal neurodevelopment. Uncertainty exists as to whether the maternal MeHg burden in Norway might affect child neurodevelopment. Objective: To evaluate the association between prenatal mercury exposure, maternal seafood consumption and child language and communication skills at age five. Methods: The study sample comprised 38,581 mother-child pairs in the Norwegian Mother and Child Cohort Study. Maternal mercury blood concentration in gestational week 17 was analysed in a sub-sample of 2239 women. Prenatal mercury exposure from maternal diet was calculated from a validated FFQ answered in mid-pregnancy. Mothers reported children's language and communications skills at age five by a questionnaire including questions from the Ages and Stages Questionnaire (ASQ), the Speech and Language Assessment Scale (SLAS) and the Twenty Statements about Language-Related Difficulties (language 20). We performed linear regression analyses adjusting for maternal characteristics, nutritional status and socioeconomic factors. Results: Median maternal blood mercury concentration was 1.03. μg/L, dietary mercury exposure was 0.15. μg/kg. bw/wk, and seafood intake was 217. g/wk. Blood mercury concentrations were not associated with any language and communication scales. Increased dietary mercury exposure was significantly associated with improved SLAS scores when mothers had a seafood intake below 400. g/wk in the adjusted analysis. Sibling matched analysis showed a small significant adverse association between those above the 90th percentile dietary mercury exposure and the SLAS scores. Maternal seafood intake during pregnancy was positively associated with the language and communication scales. Conclusion: Low levels of prenatal mercury exposure were positively associated with language and communication skills at five years. However, the matched sibling analyses suggested an adverse association between mercury and child language skills in the highest exposure group. This indicates that prenatal low level mercury exposure still needs our attention.</p>},
  author       = {Vejrup, Kristine and Brandlistuen, Ragnhild Eek and Brantsæter, Anne Lise and Knutsen, Helle Katrine and Caspersen, Ida Henriette and Alexander, Jan and Lundh, Thomas and Meltzer, Helle Margrete and Magnus, Per and Haugen, Margaretha},
  issn         = {0160-4120},
  keyword      = {Diet,Fish and seafood intake,Language development,Maternal blood levels,Methylmercury,The Norwegian mother and child cohort study},
  language     = {eng},
  pages        = {71--79},
  publisher    = {Elsevier},
  series       = {Environment International},
  title        = {Prenatal mercury exposure, maternal seafood consumption and associations with child language at five years},
  url          = {http://dx.doi.org/10.1016/j.envint.2017.10.008},
  volume       = {110},
  year         = {2018},
}