Plasma 5-aminolevulinic acid concentration and lead exposure in children

The relationship between concentration of 5-aminolevulinic acid in plasma (ALAP) and other biomarkers of lead exposure and effect was investigated in lead-exposed children. We measured ALAP by chemical derivatization and high-performance liquid chromatography with fluorescence detection. The study population consisted of 103 children: 78 from a referral clinic for children with lead poisoning and 25 from a general pediatric clinic. Blood lead concentration (PbB), age, and ALAP were higher in lead clinic subjects than in general clinic subjects. ALAP was significantly correlated with PbB (Spearman r=0.38, P=0.0007) and free erythrocyte protoporphyrin concentration (r=0.41, P=0.0002) in lead clinic subjects. PbB was a significant predictor of ALAP (P=0.0001) by multiple linear regression in all subjects. The average PbB in the 3- to 12-month period prior to blood collection correlated with ALAP to the same degree that current PbB correlated with ALAP. Possible associations between ALAP and adverse health outcomes, particularly neurobehavioral effects, should be investigated in children to assess the predictive value of ALAP for these endpoints.