Lead levels and cognitive abilities in Peruvian children.
OBJECTIVE
To study the relationship between blood lead levels and cognitive abilities of children exposed to this metal.


METHODS
This is a cross-sectional study that included 134 children aged 6 to 8.5 years old from 3 schools with different risks of lead exposure located in El Callao (Peru). Cognitive assessments were made by means of the Graphic Test of Reasoning (GTR) and the Kohs Block Design Test (KBDT). Blood lead levels and other laboratory tests were performed.


RESULTS
Children with lead > 10 ug/dl presented greater prevalence of low scores in the Graphic Test of Reasoning (18.9% vs. 7.1%, p = 0.049) and in the Kohs Block Design Test (KBDT) (39.6% vs. 18.6%, p = 0.01) compared with those with lower lead blood levels. A deficit of 1 category in the Graphic Test of Reasoning was associated with an increase in lead blood level of 16.78 ug/dl (assuming a linear relationship) and from 1 to 5.19 ug/dl (logarithmic model). For each 10 ug/dl of increase in lead levels, the Kohs Block Design Test decreases in 6.24 units (12.91 in males and 0.216 in females) (linear model), and an increase from 1 to 10 ug/dl corresponds to a drop of 16.44 points in the Kohs Block Design Test (31.19 in males and 3.98 in females) (logarithmic model). Considering the Graphic Test of Reasoning subscales, lead levels correlated negatively with the areas of numerical problems (rho = -0.445, p < 0.001), numerical relationships (rho = -0.365, p < 0.001), inferences (rho = -0.281, p = 0.002) and similarities (rho = -0.250, p = 0.005).


CONCLUSIONS
Lead levels were non-linearly associated with lower cognitive abilities, especially in males, being the numerical reasoning the most affected area.
Vega-Dienstmaier
Johann M
JM
Department of Psychiatry and Mental Health, Universidad Peruana Cayetano Heredia, Lima, Peru. jvegad@amauta.rcp.net.pe
Salinas-Piélago
Joel E
JE
Gutiérrez-Campos
María del Rosario
Mdel R
Mandamiento-Ayquipa
Ricardo D
RD
Yara-Hokama
María del Carmen
Mdel C
Ponce-Canchihuamán
Johny
J
Castro-Morales
Jorge
J
D002648:Child; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000187:drug effects*; D007361:Intelligence Tests; D007854:Lead / Q000097:blood*; D020264:Lead Poisoning, Nervous System, Childhood / Q000150:complications*; D016014:Linear Models; D008297:Male; D010568:Peru; D017678:Sex Distribution; D012737:Sex Factors
D007854:Lead