Mercury exposure and premature mortality in the Grassy Narrows First Nation community: a retrospective longitudinal study

Philibert, Aline; Fillion, Myriam; Mergler, Donna

doi:10.1016/s2542-5196(20)30057-7

Cited by 22 publications

(35 citation statements)

References 31 publications

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“…3 and 4 and in Supplementary Figs. [3][4][5][6][7][8][9][10][11][12] in Additional file 1. SEM standardized path coefficients, representing the total quantified contribution of significant direct and indirect associations, are presented in Figs.…”

Section: Resultsmentioning

confidence: 99%

Past mercury exposure and current symptoms of nervous system dysfunction in adults of a First Nation community (Canada)

Philibert

Fillion

Silva³

et al. 2022

Environ Health

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Background The watershed in Asubpeeschoseewagong Netum Anishinabek (Grassy Narrows First Nation) territory has been contaminated by mercury (Hg) since 1962, resulting in very high Hg concentrations in fish, central to the community’s culture, traditions, economy and diet. Biomarkers of Hg exposure (umbilical cord blood and hair/blood samples), monitored between 1970 and 1997, decreased over time. A recent Grassy Narrows Community Health Assessment (GN-CHA) survey included current symptoms of nervous system dysfunction. The present study aimed to cluster self-reported symptoms and examine their associations with past Hg exposure. Methods The GN-CHA included 391 adults. Symptom clustering used a two-step segmentation approach. Umbilical cord Hg and/or yearly measurements of equivalent hair Hg were available for 242 participants. Structural Equation Models (SEM) displayed the associations between Hg exposure and clusters, with Hg exposure modelled as a latent variable or in separate variables (prenatal, childhood and having had hair Hg ≥ 5 μg/g at least once over the sampling period). Longitudinal Mixed Effects Models (LMEM) served to examine past hair Hg with respect to clusters. Results A total of 37 symptoms bonded into 6 clusters, representing Extrapyramidal impairment, Sensory impairment, Cranial nerve disturbances, Gross motor impairment, Neuro-cognitive deficits and Affect/Mood disorders. Median Hg concentrations were 5 μg/L (1–78.5) and 1.1 μg/g (0.2–16) for umbilical cord and childhood hair, respectively. More than one-third (36.6%) had hair Hg ≥ 5 μg/g at least once. In SEM, latent Hg was directly associated with Extrapyramidal and Sensory impairment, Cranial nerve disturbances and Affect/Mood disorders. Direct associations were observed for prenatal exposure with Affect/Mood disorders, for childhood exposure with Extrapyramidal impairment and Cranial nerve disturbances, and for hair Hg ≥ 5 μg/g with Extrapyramidal and Sensory impairment. For all clusters, a further association between past Hg exposure and symptom clusters was mediated by diagnosed nervous system disorders. LMEM showed higher past hair Hg among those with higher scores for all clusters, except Affect/Mood disorders. Conclusion Our findings provide evidence that in this First Nation community, past Hg exposure from fish consumption was associated with later-life clusters of coexisting symptoms of nervous system dysfunction.

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Section: Resultsmentioning

confidence: 99%

Past mercury exposure and current symptoms of nervous system dysfunction in adults of a First Nation community (Canada)

Philibert

Fillion

Silva³

et al. 2022

Environ Health

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“…This review included studies with mean mercury concentrations from 0.64 to 3.71 μg/L for whole blood samples, and 0.3 to 5.7 μg/g for maternal hair ( Supplementary File Part 6 ). The findings of this review may not be applicable to populations with higher levels of mercury exposure, such as those that were reported in studies of the First Nations people in Canada [ 79 ] and the Faroe Islands [ 80 ].…”

Section: Discussionmentioning

confidence: 97%

Prenatal Mercury Exposure and Neurodevelopment up to the Age of 5 Years: A Systematic Review

Dack

Fell

Taylor

et al. 2022

IJERPH

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Neurodevelopmental delays can interfere with children’s engagement with the world and further development, and may have negative consequences into adulthood. Mercury is highly toxic and may negatively influence neurodevelopment because it can freely cross the placenta and accumulate in the fetal brain. We searched four publication databases (Embase, PsycINFO, PubMed/MEDLINE, Scopus) for studies examining the relationship between early life mercury exposure and scores on neurodevelopmental performance measures in children aged 0 to 5 years old. Study quality was assessed using the National Institutes of Health (NIH) Quality Assessment Tool. Thirty-two prospective studies were included in the review. Neurodevelopmental performance was measured using 23 different scales, most commonly the Bayley Scales of Infant and Toddler Development (BSID). In most cases, the evidence for an association between mercury and neurodevelopment was weak. There did not appear to be exceptions for particular childhood ages, outcome scales, or mercury levels. The small number of results to the contrary were more likely to be studies which did not meet our high-quality criteria, and could be a consequence of multiple testing, selection bias, or incomplete confounder adjustment. Based on current evidence, dietary mercury exposure during pregnancy is unlikely to be a risk factor for low neurodevelopmental functioning in early childhood.

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“…Sampling was not carried out regularly and samples were not collected yearly from everyone, resulting in many missing values. Moreover, there are seasonal and yearly differences in fish consumption frequency (3,6). Hg exposure imprecision is also associated with blood and hair measurements over the sampling years, notably laboratory measurement imprecision and biological variation (90).…”

Section: Discussionmentioning

confidence: 99%

“…We assembled a retrospective database using the highest measure of equivalent hair Hg concentration for each year sampled (6). Since fish consumption varied throughout the year, the corresponding month was also recorded.…”

Section: Biomarkers Of Mercury Exposurementioning

confidence: 99%

Retrospective mercury exposure and current symptoms of nervous system dysfunction in adults of a First Nation community (Canada)

Philibert

Fillion

Silva³

et al. 2021

Preprint

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Background: The watershed in Asubpeeschoseewagong Netum Anishinabek (Grassy Narrows First Nation) territory has been contaminated by mercury (Hg) since 1962, resulting in very high Hg concentrations in fish, central to the community’s culture, traditions, economy and diet. Biomarkers of Hg (umbilical cord blood and hair/blood samples), monitored between 1970 and 1997, decreased over time. A recent Grassy Narrows Community Health Assessment (GN-CHA) survey included current symptoms of nervous system dysfunction. The present study aimed to cluster self-reported symptoms and examine their relation to past Hg exposure. Methods: The GN-CHA included 391 Registered adult Band members. Symptom clustering used a two-step segmentation approach. Umbilical cord Hg and yearly measurements of hair Hg were available for 242 participants. Longitudinal Mixed Effects Models (LMEM) served to examine past hair Hg with respect to clusters. Structural Equation Models (SEM) displayed direct and indirect pathways between Hg exposure and clusters, with Hg exposure modelled as a latent variable or in separate time periods (prenatal, childhood and having had hair Hg ≥ 5µg/g at least once). Results: A total of 37 symptoms bonded into 6 clusters, representing Extrapyramidal impairment, Sensory impairment, Cranial nerve disturbances, Gross motor impairment, Neuro-cognitive deficits and Affect/Mood disorders. Median Hg concentrations were 5µg/L (1-78.5) and 1.1µg/g (0.2-16) for umbilical cord and childhood hair, respectively. More than one-third (36.6%) had hair Hg ≥ 5 µg/g at least once. LMEM shows higher long-term hair Hg among those with higher scores for most clusters. In SEM, latent Hg is directly and indirectly associated with all clusters. The contribution of prenatal exposure is mediated by childhood exposure, except for Affect/Mood disorders, where the association is direct. Hair Hg ≥ 5 µg/g is directly related to Extrapyramidal and Sensory impairment. Conclusion: Our findings provide evidence that in this First Nation community, past Hg exposure from fish consumption was associated with later-life clusters of coexisting symptoms of nervous system dysfunction. Given the complexity of the interrelations between the various determinants of chronic health problems in this and other First Nation communities, LMEM and SEM methods provide the opportunity to trace direct and/or indirect effect routes of potential “causal impact”.

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Mercury exposure and premature mortality in the Grassy Narrows First Nation community: a retrospective longitudinal study

Cited by 22 publications

References 31 publications

Past mercury exposure and current symptoms of nervous system dysfunction in adults of a First Nation community (Canada)

Past mercury exposure and current symptoms of nervous system dysfunction in adults of a First Nation community (Canada)

Prenatal Mercury Exposure and Neurodevelopment up to the Age of 5 Years: A Systematic Review

Retrospective mercury exposure and current symptoms of nervous system dysfunction in adults of a First Nation community (Canada)

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