A longitudinal study of dentine lead levels, intelligence, school performance and behaviour. Part I. Dentine lead levels and exposure to environmental risk factors.

Dentine lead levels were obtained for a sample of 996 children who were participants in a longitudinal study of child development. Mean dentine lead levels were just over 6 micrograms g-1 and had a log normal distribution. The relationship between dentine lead values and a number of variables (social background, residence in old weatherboard housing, residence on busy roads, pica) describing exposure to sources of lead was analysed. This showed that all factors made small but statistically significant contributions to variations in dentine lead values and that collectively these factors explained 10% of the variance in lead values. The implications of these results are discussed.