Article
Iron status as a covariate in methylmercury-associated neurotoxicity risk
Registro en:
FONSECA, Márlon de Freitas. et al. Iron status as a covariate in methylmercury-associated neurotoxicity risk. Chemosphere., Oxford, v. 100, p. 89-96, 2014.
0045-6535
Autor
Fonseca, Márlon de Freitas
Hacon, Sandra De Souza
Grandjean, Philippe
Choi, Anna Lai
Bastos, Wanderley Rodrigues
Resumen
Intrauterine methylmercury exposure and prenatal iron deficiency negatively affect offspring’s brain
development. Since fish is a major source of both methylmercury and iron, occurrence of negative confounding
may affect the interpretation of studies concerning cognition. We assessed relationships
between methylmercury exposure and iron-status in childbearing females from a population naturally
exposed to methylmercury through fish intake (Amazon). We concluded a census (refuse <20%) collecting
samples from 274 healthy females (12–49 years) for hair-mercury determination and assessed iron-status
through red cell tests and determination of serum ferritin and iron. Reactive C protein and thyroid
hormones was used for excluding inflammation and severe thyroid dysfunctions that could affect results.
We assessed the association between iron-status and hair-mercury by bivariate correlation analysis and
also by different multivariate models: linear regression (to check trends); hierarchical agglomerative
clustering method (groups of variables correlated with each other); and factor analysis (to examine
redundancy or duplication from a set of correlated variables). Hair-mercury correlated weakly with mean
corpuscular volume (r = .141; P = .020) and corpuscular hemoglobin (r = .132; .029), but not with the best
biomarker of iron-status, ferritin (r = .037; P = .545). In the linear regression analysis, methylmercury
exposure showed weak association with age-adjusted ferritin; age had a significant coefficient
(Beta = .015; 95% CI: .003–.027; P = .016) but ferritin did not (Beta = .034; 95% CI: .147 to .216;
P = .711). In the hierarchical agglomerative clustering method, hair-mercury and iron-status showed
the smallest similarities. Regarding factor analysis, iron-status and hair-mercury loaded different uncorrelated
components. We concluded that iron-status and methylmercury exposure probably occur in an
independent way.