Objective: To explore the gene-body mass index (BMI) interaction on coronary heart disease (CHD) in the Chinese adult twins. Methods: A total of 20 340 same-sex twin pairs registered in the Chinese National Twin Registry (CNTR) were enrolled in this study. Classical twin structure equation model was used to estimate the gene-BMI interaction on CHD. Results: After adjusting for age, we found that genetic variance of CHD differed as the function of BMI in male twins, which indicated the presence of a gene-BMI interaction on CHD (P=0.008).The genetic moderating effect (βa) was -0.14 (95%CI: -0.22--0.04), indicating that for each logarithmic transformation value of BMI increase, genetic path parameters would decrease by 0.14, which would result in the decrease of genetic variance of CHD. And the heritability of CHD was 0.77 (95%CI: 0.65-0.86) among the male twins with lower BMI (<24.0 kg/m2), but 0.56 (95%CI: 0.33-0.74) among the male twins with high BMI (≥24.0 kg/m2). However, there was no evidence suggesting that BMI could moderate genetic variants of CHD in female. Conclusion: We found a significant gene-BMI interaction on CHD in the Chinese male adult twins in China, and the heritability of CHD was higher among the twins whose BMI was <24.0 kg/m2.
目的： 分析冠心病患病的遗传-BMI交互作用。 方法： 利用中国双生子登记系统募集的20 340对≥25岁的同性别双生子，构建单变量遗传-环境交互作用模型，通过评估BMI对冠心病遗传效应的修饰作用反映冠心病的遗传-BMI交互作用。 结果： 调整年龄后，在男性中发现BMI对冠心病患病受到的遗传效应有负向修饰作用，遗传效应修饰系数（βa）及95%CI为-0.14（-0.22~-0.04），说明log-BMI每增加1个标准差，冠心病的遗传通径系数减小0.14，从而导致冠心病的遗传效应减小。而且低BMI（<24.0 kg/m2）男性冠心病患病的遗传度为0.77（0.65~0.86），而高BMI（≥24.0 kg/m2）组对应模型中的遗传度为0.56（0.33~0.74）。在女性中未观察到冠心病的遗传-BMI交互作用。 结论： 中国成年男性双生子人群中发现冠心病患病的遗传-BMI交互作用，且遗传因素在低BMI组冠心病患病中发挥更重要的作用。.