Blood and hair lead in children with different extents of iron deficiency in Karachi

Childhood iron deficiency has a high incidence in Pakistan. Some but not all studies have shown that dietary iron deficiency may cause increased absorption of lead as both compete for the same transporters in the small intestine. Therefore, children in Pakistan, residing in heavily polluted cities like Karachi may be prone to lead poisoning. This hypothesis was tested by investigating blood and hair lead concentrations in children from Karachi who were divided into four groups of iron status; normal, borderline iron deficiency, iron deficiency and iron deficiency anaemia.A prospective observational study was conducted where 269 children were categorized into four groups of iron status using the World Health Organization criteria and one based on soluble transferrin receptor measurements. Blood iron status was determined using a full blood count, serum iron, ferritin, transferrin saturation and soluble transferrin receptor measurements. Blood lead was determined by graphite atomic absorption spectroscopy, whereas hair lead was assessed using an inductively coupled plasma atomic emission spectroscopy technique.Blood lead concentrations were significantly higher in children with iron deficiency anaemia (mean [95% confidence intervals] were 24.9 [22.6–27.2] μg/dL) compared to those with normal iron status (19.1 [16.8–21.4] μg/dL) using WHO criteria. In contrast, hair lead content was not significantly different in children of different iron status. Our findings reinforce the importance of not only reducing environmental lead pollution but also the development of national health strategies to reduce childhood iron deficiency in Pakistan.

► Childhood iron deficiency is common in large cities like Karachi in Pakistan.
► This study uses two different approaches to assess iron status.
► Higher concentrations of blood but not hair lead occur in childhood iron deficiency anaemia.
► There is a need to reduce not only environmental lead pollution but also iron deficiency in Pakistan.