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Neurocognitive effects of chronic lead intoxication in Andean children
S A Counter1, L H Buchanan, H D Rosas
1Department of Neurology/Biological Laboratories, Harvard University, Cambridge, MA 02138, USA. allen_Counter@harvard.edu
Insights
Children with high blood lead levels (PbB) showed varied neurological and cognitive deficits, including impaired motor skills and reasoning. Males exhibited higher PbB levels and more neurocognitive issues, indicating significant health risks from lead exposure.
Area of Science:
- Environmental Health
- Neuroscience
- Pediatrics
Background:
- Lead (Pb) intoxication in children is linked to neurodevelopmental disabilities, motor, and cognitive impairments.
- Children in Ecuadorian villages with extensive ceramic glazing use of Pb were studied.
- Elevated blood lead levels (PbB) pose a significant risk to child development.
Purpose of the Study:
- To assess the neurological and cognitive effects of elevated blood lead levels in children.
- To investigate the relationship between PbB levels and specific neurocognitive deficits.
- To identify potential sex-based differences in lead toxicity responses.
Main Methods:
- Blood lead (PbB) measurements were taken for 96 children.
- Neurological examinations and cognitive tests (including Raven's Coloured Progressive Matrices) were administered.
- Data were analyzed to correlate PbB levels with neurological and cognitive outcomes, considering age and sex.
Main Results:
- Children with elevated PbB levels exhibited deficits in tendon reflexes, finger tapping, visual pursuit, size discrimination, draw-a-person, and math skills.
- 53.7% of children had abnormal scores on the non-verbal reasoning test (RCPM), with higher PbB levels correlating with poorer performance.
- Males showed higher mean PbB levels and a greater prevalence of neurocognitive deficits compared to females.
Conclusions:
- Chronically elevated PbB levels in children result in a spectrum of neurological responses, from tolerance to significant fine motor and cognitive deficits.
- Lead exposure significantly impacts neurodevelopment, with measurable effects on cognitive functions and motor skills.
- The findings highlight the need for interventions to reduce lead exposure in vulnerable populations, particularly considering sex-based differences.
Abstract:
Lead (Pb) intoxication in children has been associated with neurodevelopmental disabilities which may result in motor and cognitive impairment. We conducted blood lead (PbB) measurements, neurological examinations and cognitive tests on children living in Ecuadorian villages where Pb is used extensively in the glazing of ceramics. Group I consisted of 55 children with a mean PbB level of 48.0 microg/dl (SD: 26.4, range: 9.2-119.1 microg/dl) who received PbB tests and complete neurological examinations. An appreciable number of the children with elevated PbB levels were normal on specific components of the neurological examination. Among the children who showed neurological deficits, higher PbB levels were associated with abnormal tendon reflexes, finger tapping, visual pursuit, size discrimination, draw-a-person, and math calculation skills. Group II consisted of 41 children with a mean PbB level of 47.4 microg/dl (SD: 22.0, range: 6.6-84.7 microg/dl) who were administered Raven's Coloured Progressive Matrices (RCPM) non-verbal reasoning test. Performance on RCPM was abnormal in 22 (53.7%) of 41 children. Children with abnormal RCPM scores had higher PbB levels (t-test: P=0.030). There was a significant inverse correlation between RCPM scores and PbB levels for children ages 9 years and older (r=-0.618, P=0.011). Males had higher mean PbB levels as a function of age than females (t-test: P=0.037), and more males showed neurocognitive deficits. The results demonstrate a range of neurological responses in children with chronically elevated PbB levels from apparent exceptional neuro-physiological tolerance of PbB intoxication, to some fine motor and cognitive deficits.