Mustelin L, Silventoinen K, Pietiläinen K, Rissanen A, Kaprio J
Department of Public Health, Twin Research Unit, University of Helsinki, Helsinki, Finland.
Int J Obes (Lond). 2009 Jan;33(1):29-36. doi: 10.1038/ijo.2008.258. Epub 2008 Dec 2.
Both obesity and exercise behavior are influenced by genetic and environmental factors. However, whether obesity and physical inactivity share the same genetic vs environmental etiology has rarely been studied. We therefore analyzed these complex relationships, and also examined whether physical activity modifies the degree of genetic influence on body mass index (BMI) and waist circumference (WC).
The FinnTwin16 Study is a population-based, longitudinal study of five consecutive birth cohorts (1975-1979) of Finnish twins. Data on height, weight, WC and physical activity of 4343 subjects at the average age of 25 (range, 22-27 years) years were obtained by a questionnaire and self-measurement of WC. Quantitative genetic analyses based on linear structural equations were carried out by the Mx statistical package. The modifying effect of physical activity on genetic and environmental influences was analyzed using gene-environment interaction models.
The overall heritability estimates were 79% in males and 78% in females for BMI, 56 and 71% for WC and 55 and 54% for physical activity, respectively. There was an inverse relationship between physical activity and WC in males (r = -0.12) and females (r=-0.18), and between physical activity and BMI in females (r = -0.12). Physical activity significantly modified the heritability of BMI and WC, with a high level of physical activity decreasing the additive genetic component in BMI and WC.
Physically active subjects were leaner than sedentary ones, and physical activity reduced the influence of genetic factors to develop high BMI and WC. This suggests that the individuals at greatest genetic risk for obesity would benefit the most from physical activity.
肥胖和运动行为均受遗传和环境因素影响。然而，肥胖与身体活动不足是否具有相同的遗传和环境病因，这方面的研究很少。因此，我们分析了这些复杂关系，并研究身体活动是否会改变遗传因素对体重指数（BMI）和腰围（WC）的影响程度。
芬兰双胞胎16研究是一项基于人群的纵向研究，对芬兰连续五个出生队列（1975 - 1979年）的双胞胎进行研究。通过问卷调查和WC的自我测量，获取了4343名平均年龄为25岁（范围22 - 27岁）的受试者的身高、体重、WC和身体活动数据。使用Mx统计软件包基于线性结构方程进行定量遗传分析。使用基因 - 环境相互作用模型分析身体活动对遗传和环境影响的调节作用。
BMI的总体遗传度估计在男性中为79%，女性中为78%；WC的遗传度分别为56%和71%；身体活动的遗传度分别为55%和54%。男性（r = -0.12）和女性（r = -0.18）的身体活动与WC之间存在负相关，女性的身体活动与BMI之间存在负相关（r = -0.12）。身体活动显著改变了BMI和WC的遗传度，高水平的身体活动降低了BMI和WC中的加性遗传成分。
身体活跃的受试者比久坐不动的受试者更瘦，身体活动降低了遗传因素对高BMI和WC的影响。这表明肥胖遗传风险最高的个体将从身体活动中获益最大。
