Developmental and behavioural functions in young children with elevated blood lead levels.

Blood lead levels in some pre-schoolchildren living near a lead works and particularly in some children with fathers employed at the lead works showed evidence of increased exposure. Forty-seven of them took part three years later in a follow-up study of their developmental and behavioural functions. The children were aged between 4 and 5 1/2 years and were closely matched for age, sex, social class, parental education, area, and length of residence. Only three children had moved house since their blood lead levels had been examined at two years of age; these levels ranged between 18 and 64 microgram/100 ml. None of the children had clinical symptoms of plumbism. No statistically significant (P less than or equal to 0.05) differences were found on developmental and behavioural scores when the children were divided into two groups of less than or equal to 35 microgram/100 ml (n = 23) and greater than 35 microgram/100 ml (n = 24). The differences in scores were of the same order as those between boys and girls, which were themselves generally not significant. Behaviour ratings did not differ. The variations in developmental skills were generally found to be more related to age and schooling; neither these factors nor the difference in sex was related to blood lead levels.