High blood manganese in iron-deficient children in Karachi.

OBJECTIVE Dietary Fe deficiency has a high incidence in Pakistani children and may be associated with increased gastrointestinal absorption of trace metals such as Mn. Therefore, children residing in heavily polluted cities like Karachi may be prone to Mn toxicity. The present study investigated blood Mn concentrations in Karachi children of different Fe statuses. DESIGN A prospective observational study was conducted where children were classified into different categories of Fe status – normal Fe, borderline Fe deficiency, Fe deficiency and Fe-deficiency anaemia – using WHO criteria supported by measurements of soluble transferrin receptors. Blood Mn was determined for children in each category using graphite atomic absorption spectroscopy. SETTING Three hospital outpatient departments in Karachi, Pakistan. SUBJECTS A total of 269 children (156 males, 113 females) aged 6–60 months from low-income families of Karachi. RESULTS Blood Mn concentrations were significantly higher in children with Fe-deficiency anaemia and Fe deficiency compared with those of normal Fe status (both P,0?01). Blood concentrations of soluble transferrin receptors were higher in children with Fe-deficiency anaemia compared with those of borderline or normal Fe status (both P,0?05). CONCLUSIONS These findings report for the first time high blood Mn concentrations in Fe-deficient children of this age group. There is therefore an urgent need to identify and remove environmental exposure to Mn in combination with health strategies aimed at eradicating childhood Fe deficiency.