Silventoinen Karri, Hasselbalch Ann Louise, Lallukka Tea, Bogl Leonie, Pietiläinen Kirsi H, Heitmann Berit L, Schousboe Karoline, Rissanen Aila, Kyvik Kirsten O, Sørensen Thorkild I A, Kaprio Jaakko
Department of Public Health, University of Helsinki, Helsinki, Finland.
Am J Clin Nutr. 2009 Oct;90(4):1096-103. doi: 10.3945/ajcn.2009.27689. Epub 2009 Aug 26.
The development of obesity is still a poorly understood process that is dependent on both genetic and environmental factors.
The objective was to examine how physical activity and the proportion of energy as protein in the diet modify the genetic variation of body mass index (BMI), waist circumference, and percentage body fat.
Twins from Denmark (756 complete pairs) and Finland (278 complete pairs) aged 18-67 and 21-24 y, respectively, participated. The proportion of energy as protein in the diet was estimated by using food-frequency questionnaires. The participants reported the frequency and intensity of their leisure time physical activity. Waist circumference and BMI were measured. Percentage body fat was assessed in Denmark by using a bioelectrical impedance method. The data were analyzed by using gene-environment interaction models for twin data with the Mx statistical package (Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA).
High physical activity was associated with lower mean values, and a high proportion of protein in the diet was associated with higher mean BMI, waist circumference, and percentage body fat and a reduction in genetic and environmental variances. Genetic modification by physical activity was statistically significant for BMI (-0.18; 95% CI: -0.31, -0.05) and waist circumference (-0.14; 95% CI: -0.22, -0.05) in the merged data. A high proportion of protein in the diet reduced genetic and environmental variances in BMI and waist circumference in Danish men but not in women or in Finnish men.
Our results suggest that, in physically active individuals, the genetic variation in weight is reduced, which possibly suggests that physical activity is able to modify the action of the genes responsible for predisposition to obesity, whereas the protein content of the diet has no appreciable effect.
肥胖的发展仍是一个尚未被充分理解的过程，它取决于遗传和环境因素。
本研究旨在探讨身体活动及饮食中蛋白质能量占比如何影响体重指数（BMI）、腰围和体脂百分比的基因变异。
分别纳入了来自丹麦（756对完整双胞胎）和芬兰（278对完整双胞胎）的双胞胎，年龄分别为18 - 67岁和21 - 24岁。通过食物频率问卷估计饮食中蛋白质能量占比。参与者报告其休闲时间身体活动的频率和强度。测量腰围和BMI。在丹麦，采用生物电阻抗法评估体脂百分比。使用Mx统计软件包（弗吉尼亚联邦大学弗吉尼亚精神病学与行为遗传学研究所，弗吉尼亚州里士满）的双生子数据基因 - 环境交互模型对数据进行分析。
高身体活动水平与较低的均值相关，饮食中高蛋白质占比与较高的平均BMI、腰围和体脂百分比以及遗传和环境方差的降低相关。在合并数据中，身体活动对BMI（-0.18；95%置信区间：-0.31，-0.05）和腰围（-0.14；95%置信区间：-0.22，-0.05）的基因修饰具有统计学意义。饮食中高蛋白质占比降低了丹麦男性BMI和腰围的遗传和环境方差，但对女性或芬兰男性没有影响。
我们的结果表明，在身体活跃的个体中，体重的基因变异减少，这可能表明身体活动能够改变导致肥胖易感性的基因作用，而饮食中的蛋白质含量没有明显影响。
