Rottensteiner Mirva, Leskinen Tuija, Niskanen Eini, Aaltonen Sari, Mutikainen Sara, Wikgren Jan, Heikkilä Kauko, Kovanen Vuokko, Kainulainen Heikki, Kaprio Jaakko, Tarkka Ina M, Kujala Urho M
1Department of Health Sciences, University of Jyväskylä, Jyväskylä, FINLAND; 2Department of Applied Physics, University of Eastern Finland, Kuopio, FINLAND; 3Department of Psychology, University of Jyväskylä, Jyväskylä, FINLAND; 4Department of Public Health, Hjelt Institute, University of Helsinki, Helsinki, FINLAND; 5Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, FINLAND; 6Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, FINLAND; and 7Institute for Molecular Medicine, University of Helsinki, Helsinki, FINLAND.
Med Sci Sports Exerc. 2015 Mar;47(3):509-18. doi: 10.1249/MSS.0000000000000437.
The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity.
From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses.
According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P < 0.001.
Among healthy adult male twins in their mid-30s, a greater level of physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.
本研究（FITFATTWIN）的主要目的是调查身体活动水平与身体成分、葡萄糖稳态以及年轻成年男性单卵双胞胎对中身体活动不一致者的脑形态之间的关联。
从一个基于人群的双胞胎队列中，我们系统地选择了10对年轻成年男性单卵双胞胎（年龄范围32 - 36岁），他们在过去3年的休闲时间身体活动不一致。基于访谈，我们计算了过去3年休闲时间和通勤活动的平均总和指数（3年LTMET指数，以每天的MET小时表示）。我们对身体成分进行了广泛测量（包括通过双能X线吸收法测量的脂肪百分比）、葡萄糖稳态（包括稳态模型评估指数和胰岛素敏感性指数（松田指数，根据口服葡萄糖耐量试验中的葡萄糖和胰岛素值计算））以及全脑磁共振成像以进行区域体积分析。
根据成对分析，与不活跃的双胞胎相比，活跃的双胞胎具有更低的体脂百分比（P = 0.029）和稳态模型评估指数（P = 0.031）以及更高的松田指数（P = 0.021）。与不活跃的双胞胎相比，活跃双胞胎非优势半球的纹状体和前额叶皮质（脑回下和额下回）脑灰质体积更大，统计阈值为P < 0.001。
在35岁左右的健康成年男性双胞胎中，更高水平的身体活动与改善的葡萄糖稳态以及纹状体和前额叶皮质灰质体积的调节相关，独立于遗传背景。这些发现可能有助于降低后期2型糖尿病的风险和行动能力受限的风险。
