Urinary cobalt and ferritin in four-years-old children

Cobalt (Co) is an essential trace element but may cause toxic effects upon occupational or environmental exposure. The present study is aimed to determine the urine concentrations of Co in four years-old children in the INMA-Asturias cohort (Spain) and to assess the factors determining the observed levels. This cohort is located in a heavily industrialized zone with strong potential for metal exposure. Some diet components such as consumption of sweets were meaningfully associated with higher urine Co concentrations. Traffic pollution also showed a noteworthy positive association with Co levels. Family tobacco consumption did not show substantial association with the urine concentrations of this metal in the INMA-Asturias children. A significant inverse association between urine Co and venous blood ferritin was found. Iron deficiency anemic children had significantly higher concentrations of Co than those with normal levels, e.g. median values 1.9 μg/g creatinine and 1.0 μg/g creatinine, respectively. This association could be explained by an increased expression of DMT1, a divalent metal transporter that captures higher levels of iron in deficiency states of this metal. This transporter is non-specific and not only captures iron but also other divalent metals such as Co. The presence of this metal in iron deficiency anemic children may represent an additional disturbing health factor that must be considered during treatment.