From March 9, 2006
Children
Exhibit Adverse Effects From Fetal Pesticide Exposure
(Beyond Pesticides, March 9, 2006)
Children in Ecuador whose mothers were exposed to pesticides while pregnant
have increased blood pressure and diminished ability to copy geometric
figures as compared to a control group, according to an epidemiological
study in the March
issue of Pediatrics. The results appear to be independent of current
exposure to the chemicals. The mothers themselves are reported to be
healthy.
A team of researchers led by Philippe Grandjean, adjunct professor in
the Department of Environmental Health at Harvard School of Public Health
(HSPH), analyzed data on 72 children aged seven or eight years old in
the rural Tabacundo-Cayambe area in Northern Ecuador. The children were
examined by a physician and were given a battery of standardized tests
for neurobehavioral functions. Thirty-seven of the children had mothers
whose self-described occupational histories indicated that the women
had been exposed to pesticides during pregnancy, typically by working
in greenhouses. Dose-response relationships and the exact timing of
the exposures' impact were not established due to the nature of the
study design.
In the exposed children, the average systolic blood pressure is higher
than in those who were unexposed (104.0 mm Hg versus 99.4 mm Hg). An
increase in diastolic pressure is not statistically significant. Hypertension
among children and adolescents is defined based on a range of blood
pressures in healthy children, and children above the 95th percentile
are considered hypertensive. In the Pediatrics study, nine
children exceed the approximate 95th percentile of 113 mm Hg. Seven
of those children had prenatal pesticide exposure.
Prenatal pesticide exposure is also associated with a decreased ability
to copy figures presented to the children as part of a standardized
Stanford-Binet test. Adjusted regression analysis indicate that the
exposed children experience a developmental delay on this aptitude of
four years. The authors note that the confidence interval, or range
of value, for this coefficient is relatively wide but is a statistically
significant finding in a study of limited size, suggesting that the
effect could be substantial.
In the part of Ecuador in which the children live, malnourishment is
frequent. The authors used delayed growth, or stunting, to explore the
role of nutrients in the study's results. Stunting is viewed as an indicator
of malnutrition and is defined according to a height-for-age scale.
Stunting was associated with decreased copying ability in both exposed
and non-exposed children. The researchers found that stunting has no
clear effect on blood pressure. They therefore concluded that prenatal
pesticide exposure may add to the already deleterious effects of malnutrition.
Current pesticide exposure was measured by excretion of pesticide metabolites
in urine and was associated with increased reaction time, one of the
standardized tests given for neurobehavioral function, indicating that
current and prenatal exposures result in different outcomes. Effects
caused by exposure in utero may last into childhood.
"These results suggest that more attention should be paid to protecting
the developing brain and that we should seriously consider adopting
and enforcing a greater margin of safety in protecting both fetuses
and children from potential toxic exposures," said Grandjean.
For more information contact: Contact: Christina Roache, Harvard School of Public Health, [email protected], (617) 432-6052