Environmental Lead Exposure Among Preschool Children In Hefei, China: Blood Lead Level And Risk Factors

Objectives According to the cross-sectional survey of blood lead level and living habits of the children aged 0~6 in Hefei city, to analysis the blood lead level, lead poisoning rate and the exceeding detection rate of low blood lead of children aged 0~6 in Hefei city, and to discusses the influence factors of blood lead exceeding low level and the correlation with abnormal performance, which will provide evidence for further strengthening prevention of children's blood lead and taking effective intervention measures.Methods This study is a inventory survey about children's blood lead level and its related influence factors aged 0~6 years. The research objects come from 4 main districts of Hefei (Shushan, Baohe, Yaohai, Luyang) and 3 development areas (Gaoxin, Jingkai, Xinzhan), by stratified cluster sampling. 0~2 years old children were selected from the outpatient of every maternal and child health station in May of 2008 and 2009. 3~6 years old children were selected from a kindergarten of. each region to survey in these two years, and the kindergartens of these two years are different. 3394 parents of 0~6 years old children were investigated by a questionnaire survey in 2008 and 2009 in 7 districts of Hefei, using a self-administered questionnaire for the investigation, and using atomic absorption spectrometric method for blood lead measuring. Questionnaire content includes: general status, the family status, the living environment, the living habits, the health status, the feeding and diet, the clinical manifestations in children. The database was installed by EpiData3.0. Data were analyzed by SPSS11.0 software package, statistical methods include Pearson Chi-square, Mann-Whitney U test, Kruskal-Wallis H test and binary Logistic regression model.Results This study investigated a total of 3394 children aged 0~6, of which 1833 were boys (54.0%) and 1561 were girls (46.0%). Mean blood lead is 46.15μg/L, standard deviation is 23.32μg/L, median is 44μg/L, Q3(P75)=61μg/L, Q1(P25)=28μg/L. The number of children whose level of blood lead≥100μg/L was 51, the detection rate was 1.5%. The number of children whose level of blood lead≥50μg/L was 1374, the detection rate was 40.5%. Children's overall blood lead level and the exceeding detection rate of blood lead were significantly decreased in 2009 compared with those in 2008 (P<0.001). The difference of blood lead levels and the exceeding detection rates between boys and girls was not significantly (P> 0.05). Children's blood lead level of 1 and 2 years old groups were higher than those of other age groups. The lead poisoning detection rate of 2 years old group was the highest, and the exceeding detection rates of low blood lead of 1 and 2 years old groups were the highest.Children's blood lead levels in Gaoxin and Jingkai districts were higher than those in other areas, and the one in Xinzhan district was the highest in 2008. The blood lead poisoning rates of Baohe and Jingkai districs were higher in two years, while those of Xinzhan and Gaoxin districs in 2008 were higher, too. According to the children's exceeding the detection rate of low blood lead, Gaoxin and Jingkai districs were higher than the 4 main cities, while Xinzhan distric was the highest in 2008.A Binary Logistic regression model analysis showed, the risk factors of children's low level lead were: not cleaned toys, father engaged in lead-related occupation, mothers with low education, washing their hands not using soap and taking calcium, zinc and iron preparations (ORs are 1.270,1.254,1.248,1.144,1.097 respectively); the protective factors of children's low level lead were: the fuel of kitchen without coal, rarely play radio-controlled toys, the residence to the main road more than 30m, father's older, not breastfeeding (ORs are 0.916,0.864,0.830,0.802,0.708 respectively). Biting toys, aggression, difficulties of learning and anemia are the risk factors of children's low level lead (ORs are 1.353,1.295,1.285,1.277, respectively).Conclusion The blood lead levels of the children aged 0~6 showed a declining trend year by year. Detection rate of lead poisoning is at a low level, but the exceeding detection rate of low blood lead is still high, which is not received wide attention. Excessive lead pollution in the atmosphere, vocation and education of parents, bad health and lifestyle habits can cause the exceeding detection rate of low blood lead increasing. So the government departments should strengthen the supervision of lead pollution, and our doctors should be focused on the influence factors of exceeding low blood lead, do better in health education, raise children's and their parents'consciousness of preventing lead, culture good health and behavior habits.