双生子的血清脂质和脂蛋白遗传度及影响因素分析

Heritability of serum lipids and lipoproteins and its related factors in twins aged 5 to 19 years of China

目的 分析儿童、青少年的血脂指标遗传度及影响因素。方法 选择 5～ 19岁双生子2 36对 ,平均年龄 (11 2± 3 4 )岁 ,其中同卵双生子 14 3对 ,异卵双生子 93对。在DNA卵性鉴定基础上 ,以组内相关系数法及Falconer公式计算调整年龄性别前后的遗传度 ,偏态数据进行对数转换 ;校正年龄性别 ,分析相关体格、生化指标对血脂的影响。结果 同卵与异卵双生子间甘油三酯对内方差及相关系数的差异均无显著性 ;总胆固醇、高密度脂蛋白胆固醇 (HDL C)、低密度脂蛋白胆固醇 (LDL C)和脂蛋白 (a)对内方差及相关系数的差异有显著性 ,遗传度估计值分别为 0 5 6、0 5 5、0 4 9和 0 5 8,调整年龄性别后各指标估计遗传度分别为 0 6 3、0 6 3、0 5 5和 0 6 4。总胆固醇、HDL C、LDL C和脂蛋白(a)与年龄呈负相关 ;女孩的总胆固醇、HDL C、LDL C稍高于男孩。校正年龄性别后除脂蛋白 (a)外各血脂指标多数与体重指数、体脂率及培利迪西指数相关 ,与血压、血糖和血钙等也有相关性。结论 总胆固醇、HDL C、LDL C和脂蛋白 (a)受遗传因素影响较大 ,而甘油三酯主要受环境因素影响。儿童的血脂水平受年龄和性别的影响 ,与反映体脂和机体营养发育的指标相关。

Objectives To study the contribution of the genes and environment to variation of serum levels of lipids and lipoprotein. Methods One hundred and forty-three healthy monozygotic (MZ) twin pairs and 93 dizygotic (DZ) ones aged 5 to 19 [with a mean of (11.2±3.4) years]. Microsatellite polymorphism (STR) was used to diagnose zygosity of twins,and intraclass correlation coefficient method and Falconer formula were performed to investigate heritability of serum lipids and lipoproteins unadjusted or adjusted for age and sex. Logarithmic transfomation was used for data with skewed distribution. Influence of relevant physical and biochemical indicators on serum lipids and other components was analyzed with partial coefficients of correlation adjusted for age and sex. Results In the twin samples,difference in serum level of triglycerides (TG) between MZ and DZ was not statistically significant with intraclass variation and intraclass correlation. There was significant difference in serum levels of total cholesterol (TC),high-density lipoprotein-cholesterol (HDL-C),low-density lipoprotein-cholesterol (LDL-C),and lipoprotein [Lp(a)] between MZ and DZ,with their heritability estimates of 0.56,0.55,0.49 and 0.58 unadjusted,respecitvely,and 0.63,0.63,0.55 and 0.64 adjusted for age and sex,repsectively. Serum levels of TC,HDL-C,LDL-C and Lp (a) correlated reversely with age. Serum levels of TC,HDL-C and LDL-C in girls were sightly higher than those in boys. Most indicators for serum levels of lipids and lipoprotein,except for serum level of Lp(a) correlated with body mass index (BMI),body fat ratio,Pelidisi index,and other indexes such as blood pressure,blood sugar,serum level of calcium,adjusted for age and sex. Conclusions Serum levels of TC,HDL-C and Lp(a) were influenced more greatly by genetic factors, and serum level of TG was mainly influenced by envirnmental ones. Levels of blood lipids in children were influenced by age and sex,and correlated with indicators that reflect their body fat and nutritional status.