Bioelectrical impedance analysis (BIA)-derived phase angle (PhA) is a valuable parameter to assess physical health. However, the genetic and environmental aspects of PhA are not yet well understood. The present study aimed to estimate the heritability of PhA and investigate the relationships between PhA and anthropometric measurements. PhA and skeletal muscle mass index (SMI) were examined using multi-frequency BIA in 168 Japanese twin volunteers (54 males and 114 females; mean age = 61.0 ± 16.5 years). We estimated the narrow-sense heritability of these parameters and the genetic and environmental relationships between them using a genetic twin modeling. For the PhA, 51% (95% confidence interval: 0.33, 0.64) of the variance was explained by additive genetic effects, and 49% (95% confidence interval: 0.36, 0.67) was explained by unique environmental effects. The heritability of PhA was lower than the height, body weight, and body mass index. PhA shared almost no genetic variation with anthropometric measurements and SMI but shared an environmental variation (14%) with SMI. These findings suggest that the genes affecting PhA are different than those affecting anthropometric measurements and SMI. The correlation between PhA and SMI is caused by common environmental factors.

中文翻译：

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相角的遗传力和环境相关性与人体测量：一项孪生研究

生物电阻抗分析（BIA）衍生的相角（PhA）是评估身体健康状况的重要参数。但是，PhA的遗传和环境方面尚不十分清楚。本研究旨在评估PhA的遗传力，并研究PhA与人体测量之间的关系。使用多频BIA对168位日本双胞胎志愿者（54位男性和114位女性；平均年龄= 61.0±16.5岁）进行了PhA和骨骼肌质量指数（SMI）的检查。我们使用遗传双生模型估计了这些参数的狭义遗传力以及它们之间的遗传和环境关系。对于PhA，通过累加遗传效应解释了51％（95％置信区间：0.33，0.64）的方差，以及49％（95％置信区间：0.36，0）。67）由独特的环境影响来解释。PhA的遗传力低于身高，体重和体重指数。PhA与人体测量和SMI几乎没有遗传变异，但与SMI共有环境变异（14％）。这些发现表明，影响PhA的基因与影响人体测量和SMI的基因不同。PhA和SMI之间的相关性是由常见的环境因素引起的。