Aims Exposure to Lead is still an ongoing problem in children. High blood levels have been associated with global developmental delay and learning difficulties. In the UK there is no reliable data on the current prevalence of clinically significant lead toxicity or elevated blood lead concentration in children. British Paediatric Surveillance Unit (BPSU) has just completed a surveillance programme which aimed to estimate the extent of the problem using a blood lead levels (BLL) cut off of >0.483 μmol/L. Currently, Centre for Disease Control, USA (CDC) recommends a BLL of 0.24 μmol/L to be used to trigger lead education, environmental investigations, and medical monitoring. According to WHO a BLL <0.483 μmol/L is agreed upon as the level which can cause neuro-cognitive effects in children. This study was aimed at determining the prevalence high BLL in children being investigated for unexplained global developmental delay and learning difficulties in Leeds & Wakefield, UK.
Methods Lead levels were requested for children being investigated for global developmental delay or learning difficulty in Leeds and Wakefield areas. Number of children with high lead levels were identified using cut offs of 0.24 and 0.483 μmol/L and the prevalence was calculated over a period of 18 months.
Results 104 children were included (76% males). The mean BLL (+/- Standard Deviation) was 0.12 +/- 0.14. Nine (9%) children had BLL >0.24 and 1 (1%) >0.483 μmol/L. All of them were males.
Conclusion Our study showed that the prevalence of high BLL as per criteria used by BPSU is low in Leeds & Wakefield region but it is 9 times higher if we use a lower BLL (i.e. 0.24 μmol/l) as the cut off as recommended by WHO. We suggest inclusion of BLL as a standard investigation for global developmental delay and learning difficulty, acting as a targeted screening tool, and to start environmental investigations as per HPA protocol at a lower BLL of 0.24 μmol/l.