The polymorphisms of MGP gene and ALAD gene were analyzed by the methods of PCR-RFLP.

采用多聚酶链反应-限制性片段长度多态性法(PCR - RFLP)分析MGP和ALAD基因的多态性。

After controlling these possible confounding variables by multiple regression, the contribution of the ALAD isozyme phenotype to the blood lead levels was still statistically significant.

采用多元逐步回归分析，发现ALAD基因型对血铅水平的影响在排除协变量影响后仍有极显著的统计学意义。