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[Lower lead exposure and mental development].

Children were divided into two groups based on their blood lead levels(< 10 or > or = 10 mg/dl). The mental development indexes(PDI, VIQ, PIQ and FIO) were significantly decreased in the high lead group. Simple correlation analysis indicated that there was a negative association between blood lead levels and PDI, VIQ, PIQ and FIO(r = -0.1458, -0.3330, -0.2316 and -0.3133 respectively). But multiple regression analysis showed that the indexes of mental development were not associated with blood lead levels. It is concluded that lead is probably one of the risk factors hindering mental development. But the effect is weak while the blood lead level is not high enough.