[Evaluating the effectiveness of child lead poisoning prevention programs].

PROBLEM

A multi annual screening and prevention program against lead poisoning was implemented in a suburb of the Paris area. We attempted to assess the effectiveness of this program based on data available from children screening and follow-up.

METHODS

Indicators of effectiveness included the evolution of blood lead levels at screening and the frequency of secondary increases in blood lead levels. Buildings inclusion dates were used to control for the increasing selection of less exposed children.

RESULTS

A total of 3,660 children were screened between 1992 and 2000. We observed a regular decrease in blood lead levels at screening, in the highest blood lead levels obtained for each child and in the proportion of children whose blood lead levels increased after screening: the proportion of children with initial blood lead levels >=15 micro g/dl fell from 17.4% in the 1992-1996 period to 4.1% in the 1997-2000 period. A multivariate analysis taking into account the first year that children were screened in a given building showed that less exposed children were included over time, but found also an additional independent decrease in blood lead levels that can be related to the effectiveness of prevention efforts. A "building by building" analysis of 30 buildings where more than 20 children were located over the whole study period confirmed that the incidence of lead poisoning decreased within most of these buildings.

CONCLUSIONS

Taking into account buildings'inclusion dates makes it possible to distinguish program effectiveness from the consequences of including less exposed children The effectiveness of preventive actions is associated with several interacting factors, including the participation of families and the active involvement of local technical staff and policy makers. The finding that the decrease in blood lead levels leveled off after 1997 calls for further actions.