Lead, poor food pose health risks for Karachi's kids.
Rahman, MA, B Rahman, MS Ahmad, A Blann and N Ahmed. 2012. Blood and hair lead in children with different extents of iron deficiency in Karachi. Environmental Research http://dx.doi.org/10.1016/j.envres.2012.07.004.
Studies in Pakistan and other similarly developing countries have shown that children with low iron levels in their blood are also more likely to have higher blood lead levels when compared to kids with iron levels in the normal range. One from Islamabad, Pakistan, found the association in children who lived with people who worked in lead battery recycling and smelting plants when compared to kids who lived far away from these industries (Khan et al. 2011).
Iron is a nutrient supplied through diet. It is an essential component of the oxygen-carrying hemoglobin found inside red blood cells.
Low levels of iron – or anemia – affects an estimated 64 percent of children between the ages of 6 months and 4 years in Karachi, Pakistan. For comparison, that number is 9 percent among children between 1 and 3 years old in the United States.
Iron deficiency can have profound health effects. In children, a lack of iron can decrease growth rate, alter motor skills and lower IQ.
Children in Pakistan can be iron deficient for two main reasons. One, they don’t consume foods with sufficient iron levels. In some cases, this can happen when young children drink cow's milk as their main source of nutrition. Second, the children may rely on foods that inhibit iron absorption in the gut. Chapati – a widely eaten flat bread in Pakistan – is one of these.
Generally, children's lead levels have declined in Pakistan due to the 2001 ban on lead in gasoline. But, environmental lead contamination is still widespread. Infants and children continue to be exposed to harmful levels through leaded paint and lead-laden water.
Both sources are still prevalent in Karachi. More than 80 percent of the children in this industrialized, polluted city have blood lead levels higher than the U.S. Centers for Disease Control's action level of 5 micrograms per deciliter (µg/dL) of blood.
Elevated blood lead levels can have a range of health effects. These include decreased IQ as well as stomach pain and fatigue.
The previous studies on the relationship between iron and lead, though, yield mixed results.
Muhammad Ataur Rahman and his research team enrolled 269 children aged 6 - 60 months old who had visited one of three different clinics between 2006 and 2008 in the highly populated areas of Karachi, Pakistan.
Lead and iron levels were measured in the children's blood. The children were assigned to one of four groups based on decreasing iron levels: normal, borderline deficient, deficient and iron deficient anemia. The authors compared mean levels among the four groups and looked for an association between high lead levels and low iron levels in blood.
To compare techniques, they also analyzed lead levels in the children's hair. They found the blood lead measures were a better overall marker of lead exposure than hair.
Mothers filled out questionnaires about age, illnesses, parental nutrition, sex, diet and socioeconomic factors, among other things.
All of the children in the study had blood lead levels above the U.S. Centers for Disease Control and Prevention (CDC)’s threshold of 5 µg/dL. Their levels ranged from 5.2 to 86.2 µg/dL.
The children with major iron deficiencies had significantly higher blood lead levels than those whose nutritional iron status was in the normal range.
Children who were the most iron deficient – that is, they had iron deficiency anemia – had mean blood lead levels of 24.9 µg/dL, while those in the normal range had levels of 19.1 µg/dL, using World Health Organization criteria.
The researchers found that children up to 3 years of age (36 months) were most likely to have the highest blood lead levels and the lowest iron levels.
Children from Karachi, Pakistan, who had severe anemia also had significantly higher levels of lead in their blood than children with normal iron levels. The children lived in a poorer and densely populated area of the large city.
The study is important because it is among the first to use robust analytical measurements to explore the relationship between the children's iron and lead levels. The group of children was large enough to observe differences among four groups of iron status. Additionally, the study was based in local clinics and did not specifically target children whose family members worked in lead-using industries.
A number of other studies have also documented the relationship, with mixed results. Many show that the children with the lowest iron levels often have the highest blood lead levels. But other studies are not so clear cut.
This study addresses some of that confusion. The results support the multiplicative effects of poor nutrition and lead exposure found in previous studies. However, the results are still unclear about which comes first – the iron deficiency or the lead exposure – and if one leads to the other.
Children with iron deficiencies are inclined to behaviors that may increase lead exposures. For instance, anemic children will eat non-food substances like soil and paint chips, a condition known as pica, that could increase their lead ingestion if they are in a lead-contaminated environment. On the other hand, lead can cause anemia by inhibiting certain body processes.
Moreover, this is largely an issue of what's called "compound disadvantage." It is often families of lower socio-economic status that are affected by both problems. The deficiencies are very big health-related problems. While this study centered on Pakistan, the problems most likely occur in other rapidly industrializing countries whose environmental health regulations meant to protect people from hazards like lead are not keeping pace with development.
Drinking water can be a major source of lead exposure as a recent paper suggests (Ul-Haq et al. 2011). Some disinfectants – including chloramine – are known to hasten lead's release from pipes into drinking water. In those cases, water disinfectant systems could be re-examined .
The authors note that Pakistan needs better rules and regulations to reduce the ubiquitous use of lead-based products, such as paint. Information campaigns would help educate parents of the potentially severe health consequences of lead exposure for their infants and children as well as the nutritional importance of iron.
Bradman, A, B Eskenazi, P Sutton, M Athanasoulis and LR Goldman. 2001. Iron deficiency associated with higher blood lead in children living in contaminated environments. Environmental Health Perspectives 109:1079–1084.
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Lead effects on children