Blood lead levels among children aged 0 to 6 years in 16 cities of China, 2004-2008

Abstract

Background The adverse health effects of lead for children under 6 years are well known. Studies to assess the lead exposure among children in China are small in sample size and lack of national representative data. The aim of this study therefore was to describe blood lead levels and identify risk factors for lead exposure among children aged 0 to 6 years living in 16 cities in China. Methods We analyzed data from blood lead levels surveillance in China carried out in 16 large cities between 2004 and 2008. A stratified clustered random sampling strategy was used. A total of 69 968 children aged 0 to 6 years were included. We conducted multiple Logistic regression analyses to explore risk factors to high blood lead level. Results The geometric mean blood lead level of the children was 4.50 μg/dl (median: 4.90 μg/dl; IQR: 3.20-7.00 μg/dl). Overall prevalence of blood lead level ≥10.00 μg/dl among 0- to 6-year-old children was 7.57%. But the proportion of blood lead level ≥5.00 but <10.00 μg/dl was 42.12%. Blood lead levels were significantly higher in boys (4.63 μg/dl) than in girls (4.35 μg/dl) (P <0.0001). The geometric mean blood lead levels and prevalence of blood lead level ≥10.00 μg/dl increased with age (P <0.0001 for the two trends). After controlling for sociodemographic, dietary and behavior factors, multivariable analysis indicated that lower maternal education, male gender, younger age, often biting pencil or/and toys, walking or playing for long time on the street, not washing hands before eating are major risk factors for higher lead levels. Conclusions The blood lead levels among Chinese children in urban areas are lower than previous studies but close to those of developed countries. However, children with low lead exposure account for almost half and the sociodemographic factors (age, male sex, and low mother education level) continue to be associated with higher blood lead levels.