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Detection of early neurotoxicity in children with environmental methylmercury exposure

Objective

i) Identification of population groups at risk of neurotoxic effects due to methylmercury exposures.
ii) Development and validation of evoked potentials from the brain as an early and potentially reversible indicator of neurotoxicity in children exposed to environmental pollutants;
iii) Evaluation of the possible relationship between prenatal exposure to methylmercury and early neurbehavioural dysfunctions as indicated by evoked potentials and other parameters.


Methylmercury from marine food items may constitute a risk for neurotoxic effects, especially when the diet of pregnant women causes exposure of the foetus. In certain populations that mainly rely on seafood, methylmercury exposures may be substantial.

A dietary questionnaire and interview study will be carried out in at least two island communities, i.e. the Tyrrhenian area, the Azores, Madeira, and/or the Canary Islands. Subsequently, marine biota that constitute a significant part of human diet, will be sampled for mercury analysis. Detailed community studies will be carried out to determine the methylmercury burden, especially in pregnant women (or women of child-bearing age) and small children.

Clinical studies will then be undertaken to determine the possible presence of neurotoxic effects related to methylmercury exposures. In the Faroe Islands, a cohort of children followed since birth will be examined at age 6-7 years. In Thule, Greenland, a small group of Inuit children will be examined to provide information on the effects of very high exposures and the possible genetic differences in susceptibility. A larger group of Italian children representing different exposure levels in the Tyrrhenian area will also be examined.

In the clinical studies, the exposures of each child will be evaluated in detail. In addition to interview data on past medical history and current developmental status, the following methods will be used:

i) Neuropaediatric examination.
ii) Neuropsychological examination of mental development.
iii) Evoked potentials from the brain, including both visual and auditory-brain stem.
iv) Neurophysiological and sensory tests.

In particular, evoked potentials may represent an indicator of early, but reversible effects on the nervous system. The sensitivity of the evoked potentials will be evaluated on the basis of their relation to methylmercury exposures. The validity will be assessed by comparison with the results of the other tests conducted.

There is also strong collaboration with research groups in the USA and Japan.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Odense Universitet
Address
17,Winsloewparken
5000 Odense C
Denmark

Participants (3)

UNIVERSITY OF AARHUS
Denmark
Address
180,Vennelyst Boulevard, 6
8000 Aarhus C
UNIVERSITY OF SOUTHERN DENMARK - UNIVERSITY OF ODENSE
Denmark
Address
55,Campusvej 55
5230 Odense
Università degli Studi di Siena
Italy
Address
Via P. A. Mattioli 4
53100 Siena