Objective To investigate the correlation of blood lead and cadmium levels with physical development in school-aged children in a polluted mining area of Guangxi Zhuang Autonomous Region, China.
Methods The children, aged (5-14) years, who lived in five villages which might be polluted by a mine in Guangxi Zhuang Autonomous Region were selected as respondents in 2013—2014. A questionnaire survey was performed for these children, and physical examination was performed to measure the growth and development indices including body height and body weight. Inductively coupled plasma mass spectrometry was used to determine the levels of lead and cadmium in whole blood. The children were divided into Q1-Q4 groups according to the quartiles of blood lead and cadmium levels, and the multivariate logistic regression model was used to analyze the correlation of blood lead and cadmium levels with physical development.
Results A total of 294 children were collected as respondents, and the geometric means of blood lead and cadmium levels in these children were 36.96(95%CI: 35.41-38.59) μg/L and 1.21(95%CI: 1.15-1.27)μg/L, respectively. The rate of developmental delay was 19.4%. The multivariate logistic regression model showed that after adjustment for the factors including age, gender, behavior, and dietary habits, compared with the Q1 group in terms of blood lead level, the Q2-Q4 groups had odds ratios(95%CI)for developmental delay of 3.04(0.76-10.12), 4.54(1.21-13.64), and 6.89(1.75-21.29), respectively. Compared with the Q1 group in terms of blood cadmium level, the Q2-Q4 groups had odds ratios (95%CI) for developmental delay of 2.32(0.73-7.36), 4.17(1.28-13.65), and 3.57(1.08-11.78), respectively.
Conclusion Blood lead and cadmium levels are negatively correlated with physical development in children, which should be taken seriously.
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