Children aged under 5 years are at increased risk of lead poisoning. Age - compared to an adult, a child can absorb twice as much lead from the GI tract.Older houses (lead-based paint or pipes).Associated iron deficiency - increases lead absorption from the GI tract.Use of various imported tonics, alternative medication and cosmetics containing lead.Deliberate ingestion (pica) is occasionally seen in adults as part of a psychiatric condition.Children chewing lead-painted items or ingesting fishing weights, bullets or contaminated soil.The risk of toxicity increases with increasing exposure. Occupations involving contact with lead-containing products are radiation shields, ammunition, certain surgical equipment, developing dental X-ray films prior to digital X-rays, fetal monitors, plumbing, circuit boards, jet engines, and ceramic glazes.The occupations mainly involved are the smelting, refining, alloying and casting industry (19.1%), the lead battery industry (18.2%) and the scrap industry (7.4%). In adults, lead poisoning is mostly occupation-related. Younger children are particularly at risk because of ingestion of foreign material, increased gastrointestinal (GI) absorption and because their nervous systems are still developing. Lead poisoning is a lot less common than it used to be with less use in petrol, paints or cosmetics and generally improved housing.The effect of long-term elevated lead levels on children is of particular concern and can lead to a reduction of IQ and to disruptive behaviour.īlood lead levels of less than 5 µg per dL are associated with impairments in neurocognitive and behavioral development that are irreversible. Chronic lead poisoning may be either environmental or occupational. Īcute lead poisoning is mainly related to occupational inhalation and foreign body ingestion. Īnother showed a significant increase in the frequency of chromosomal aberrations in workers exposed to lead compared to the controls. One study showed altered hippocampal volume and brain metabolites in workers occupationally exposed to lead. Lead also depresses haem synthesis and shortens the lifespan of erythrocytes, causing a hypochromic microcytic anaemia. Lead poisoning can cause nervous system toxicity and renal tubular dysfunction leading to irreversible interstitial nephrosis with progressive renal impairment and hypertension. Lead exposure also affects calcium metabolism. This effects erythrocyte formation by impairing haem synthesis and also depresses the serum level of erythropoietin. Lead inhibits 3 enzymes of haem biosynthesis (δ amino levulinic acid dehydratase (ALAD), coproporphyrin oxidase, and ferrochelatase).
The biological effects of lead are dependent on the level and duration of exposure.
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