DDT in human milk and mental capacities in children at school age: an additional view on PISA 2000.

OBJECTIVES: To investigate a possible lasting impact of dichlorodiphenyl trichloroethane (DDT) exposure in neonatal life on mental capacities in later life.

MATERIAL AND METHODS: Relationships were evaluated by correlation and regression analysis between total DDT concentrations in human breast milk in the years of birth (1984/1985) and measurements of mental capacities obtained in pupils of the PISA 2000 studies as well as percentages of backward children in Germany in 1994/95.

RESULTS: Comparing total DDT levels in human milk during the years of birth (1984/85) evaluable for eleven PISA countries with assessed mental capacities of 15-year-old pupils of PISA International, a significant inverse correlation was found (p < 0.001), even after adjustment for socioeconomic statuses (p = 0.001). Furthermore, a significant inverse correlation (p < 0.001) was also obtained between the total DDT concentrations in human milk in 1984/85 in ten foreign countries of three continents plus fourteen Federal States of Germany and the mental capacities of 15 year-old pupils of PISA International plus PISA National (Germany) 2000. Finally, a significant positive correlation was observed between total DDT contents in human milk in 1984/85 and the percentages of backward school children in 1994/95 in Federal States of Germany (p < 0.001).

CONCLUSIONS: These data in association with additional experimental and epidemiological findings suggest that DDT is a "neuroendocrine disrupter" as well as a "functional teratogen" leading to harmful effects on brain development and mental capacities in later life. Thus, a neuroendocrine prophylaxis during critical developmental periods in early life as recommended by our group since many years appears to be most important for primary preventive medicine but even for "preventive pedagogics". The validity of these theses should be re-tested in future PISA studies.