Is there an influence of maternal lead exposure on infantile development?

摘要

BACKGROUND : Infantile development could be affected by lead exposure during gestational period. We analyzed the influence of lead on twelve-month-old and twenty-four-month-old infants using Bayley Test. METHODS : This study is a part of MOCEH study which is an on-going, prospective birth cohort study in South Korea. Bayley test (K-BSID- Ⅱ) was conducted to measure infantile neurodevelopment when the children became 6,12, and 24 months of age and mental developmental index(MDI) and psychomotor developmental index(PDI) from the test were used for outcome variables. We used the t-test in order to find differences and used multivariate analysis so as to control the variables. We used 'Time-varying effect model' and 'Linear mixed model' to find best fitted regression model. In addition, we used generalized additional model to see relationship between maternal Pb levels and infantile Bayley score. RESULTS : When we fitted the regression model to concentrations of lead on the Bayley score, we could assure that the slope-retrogressive point exist at the very low spot of the concentration of lead (Specifically, slope-retrogressive point was 1.00 with total's, 0.97 with 6months', 1.02 with 12 months', 0.98 with 24 months'PDI). Over the slope-retrogressive point, we found that Bayley score decreases with increase of lead levels significantly (beta = -0.23, p-value ＜0.001). Bayley score at 6 ,12, and 24 months, were significantly reduced by -0.28, -0.23, and -0.15 in PDI. CONCLUSION : As a result, we found that the concentration of lead is inversely proportional to the Bayley score of the infants. In comparison with Bayley score of the 12 months' infants, the 24 months' score was less influenced by the concentration of lead.