[Study on the distribution and correlation of trace elements in whole blood of children in Beijing].

Objective: To study the distribution and correlation of trace elements in peripheral blood of children in Beijing so as to offer scientific evidence for the supplementation of trace elements and to prevent lead intoxication.

Methods: Contents of trace elements in whole blood of 13 929 children in Beijing region were detected by Atomic Absorption Spectrometer. According to developmental condition, children were divided into young infancy group, infancy group, toddler's age group, preschool age group, school age group and adolescence group. Every group was divided into males and females. Distribution and correlation of trace elements in different age groups and in different sex sets were then analyzed and compared.

Results: The level of copper, calcium and magnesium were stable in different age groups and in different sex sets. There were no obvious significant differences in age groups and sex sets and there were no deficiency of copper, calcium and magnesium discovered. The level of zinc increased gradually following the growth of age and the level of zinc was (81.71 +/- 15.91) micromol/L. There were significant differences in different age groups noticed as well in sex sets of infancy group, toddler's age group and preschool age group. The rate of deficiency of zinc decreased gradually following the growth of age. The rate of zinc deficiency was 13.7% and there were obvious differences noticed in sex sets of toddler, preschool and school age groups. The level of iron increased gradually following the growth of age with the level of iron as (8.28 +/- 0.78) mmol/L. There were significant differences noticed in different age groups, after infancy stage. There was significant difference noticed also in sex sets after school age group. The rate of iron deficiency decreased obviously following the growth of age. The iron deficiency rate was 12.9%, and significantly different in sex sets of young infancy, school age and adolescence groups. The level of lead increased gradually following the growth of age, with the overall level as (59.97 +/- 26.52) microg/L; There was an obvious significant differences noticed in different age groups with significant differences noticed in sex sets after toddler's age group. The rate of lead intoxication increased gradually following the growth of age. The rate of lead intoxication was 8.2%. There were significant differences noticed in sex sets after toddler's age group. However, there were negative correlations noticed among the levels of lead and copper, zinc, calcium, magnesium and iron. There were no correlations between the level of calcium and iron found but showed positive correlation among other trace elements.

Conclusion: The deficiency of calcium was basically corrected but the deficiency of zinc and iron were still obvious. There was a high level of lead noticed in these children. It is important to advocate on healthy feeding program, on culture good hygienic habit and on away from the lead pollution sites.