济宁市6～14岁双生子血铅水平调查及遗传度分析

Investigation of Blood Lead Level and Analysis of Heritability in Twins Aged 6 -14 Years in Ji’ning City,Shandong Province,China

目的了解济宁市双生子血铅水平,探讨遗传因素和环境因素对儿童血铅水平的影响。方法于2008年6月,随机抽取济宁市144对同性别6～14岁双生子作为研究对象,测定其血铅含量并进行评价[分为相对安全(血铅<60μg/L)、超标(60μg/L≤血铅<100μg/L)、铅中毒(血铅≥100μg/L)]。在DNA卵型鉴定基础上计算血铅的遗传度。结果经卵型鉴定,144对双生子中同卵双生子76对,异卵双生子68对;血铅含量相对安全的占62.50%,超标的占23.61%,铅中毒的为13.89%,三者在性别间分布差异无统计学意义(χ2=4.077,P=0.130)。双生子血铅含量为(58.80±40.30)μg/L,不同性别、年龄间差异无统计学意义(t性别=0.17,P=0.87;F年龄=1.37,P=0.21)。儿童铅中毒发生率和血铅含量在9～11岁均出现突增现象,9～10岁女童高于男童,但差异均无统计学意义(P>0.05)。经遗传度分析,血铅含量的遗传度为9.19%。结论影响血铅含量的遗传因素作用远小于环境因素作用。

Objective To know the blood lead level among twins in Ji＇ning,Shandong province, China and to assess the genetic and environmental influence on blood lead level of children. Methods A total of 144 pairs of same sex twins aged 6-14 years were randomly selected in June, 2008, and their blood lead level was determined and assessed into three groups, namely the relatively safe group （blood lead level〈60 μg/L）, the exceeded standard limit group （60 μg/L ≤ blood lead level〈 100 μg/L） and the lead poisoning group （blood lead level ≥ 100 μg/L）. The heritability of blood lead was calculated on diagnosis basis of DNA zygosity. Results The results of zygosity diagnosis showed that 76 pairs of twins were monozygotic （MZ） twins and 68 pairs were dizygotic （DZ） twins. About 62.50% of subjects were in the relatively safe group,while 23.61%, 13.89% were in the exceeded standard limit group and lead poisoning group,respectively,with no statistical significance found in different sex （Х^2=4.077,P= 0.130）. The average level of blood lead in twins was （58.80±40.30） μg/L,with no statistical significance found in different sex and age （tsex=0.17,P=0.87 ;Fage=1.37,P=0.21）. Heritability analysis demonstrated that the heritability of blood lead level was 9.19%. Conclusion Blood lead level can be influenced by environmental factors much more than by genetic factors.