Lead in children from older housing areas in the Wellington region

To examine blood lead levels in children, aged 12 to 23 months, living in old housing areas of Wellington and Lower Hutt, and to investigate risk factors for high lead levels.

Children were selected from Plunket Society rolls. Venous blood samples were collected, and care givers were interviewed with a questionnaire. Soil samples were taken from around the children's homes. Both soil and blood samples were analysed for lead content.

Blood samples and completed questionnaires were obtained for 143 children. The geometric mean blood lead level for all the children was 0.25 mumol/L (5.1 micrograms/dL) (95% confidence interval [95% CI]: 0.22-0.28 mumol/L). Three children had blood lead levels that exceeded the level for notification in New Zealand 1.45 mumol/L and a further 13 had blood lead levels exceeding 0.48 mumol/L. Children with elevated lead levels were likely to live in a house greater than 50 years old where paint removal had taken place in the last 2 years (risk ratio [RR] = 14.4, 95% CI: 2-107). Eating dirt, particularly for children who usually played outside within 2 metres of the house, was also a risk factor for elevated blood lead levels. Soil lead levels generally increased with the age of the house and were weakly correlated with blood lead levels (r = 0.32).

Paint removal in old houses is a major risk factor for elevated blood lead levels. However, the number of study children living in houses less than 50 years old was limited. Because of this and possible participant selection bias, the results of this study require confirmation in a separate population-based study. Information about the specific paint removal procedures that cause high lead levels is also needed.