Neurobehavioural consequences of prenatal low level exposures to lead.

A cohort of 318 children born in three Sydney hospitals between April 1982 and March 1983 were recruited into a five year prospective study designed to investigate the relationship between low level lead exposures and neurobehavioural development. Blood samples were obtained at the time of birth, then at 6 month intervals to 4 years and then at 5 years; neurobehavioural and physical measures were taken at 6 months, 12 months and hence annually to 5 years. This paper presents some of the findings from the first three years of the study and addresses the issue of the relationship between fetal exposures to lead and child development to three years. Maternal and cord blood lead levels were in range 0-29 microgram/dl with the majority less that 15 micrograms/dl. The geometric means were, respectively, 9.1 micrograms/dl and 8.1 micrograms/dl. The analyses presented do not support the hypothesis of a relationship between maternal and cord blood lead levels in this range and developmental deficits in young children to the age of three years.