Food, Nutrition & Health, School of Public Health, Faculty of Health Sciences, Curtin University, Perth, WA, 6845, Australia.
Flinders Centre for Epidemiology and Biostatistics, Health Science Building, Flinders University of South Australia, GPO Box 2100, Adelaide, SA, 5001, Australia.
Eur J Clin Nutr. 2018 Oct;72(10):1421-1430. doi: 10.1038/s41430-017-0058-x. Epub 2018 Jan 11.
BACKGROUND/OBJECTIVES: Cold exposure increases thermogenesis and could improve insulin sensitivity. We hypothesized a blunted response in the metabolic syndrome (MetS).
SUBJECTS/METHODS: Twenty older adults 59 ± 10.4 years (with MetS, MetS+, n = 9; without MetS, MetS-, n = 11) completed a randomized crossover design of 3.5 h exposures to 20, 25 and 27 °C on three visits. After an hour's rest at the desired temperature, resting metabolic rate (RMR), respiratory quotient (RQ), forearm to fingertip gradients (FFG), and in the ear temperature (IET) were measured over 30 min. An oral glucose tolerance test followed, and serial measurements were continued for 2 h. Venous blood was sampled for clinical chemistry, irisin, and fibroblast growth factor 21(FGF21). A mixed model ANCOVA adjusted data for age, gender, fat mass, fat-free mass and seasonality.
There was a significant MetS×temperature interaction where adjusted RMR was significantly higher in MetS+ compared to MetS- by 12% at 20 °C and by 6% at 25 °C, but similar at 27 °C. FFG increased and IET decreased with decreasing temperature to the same extent in both groups. Fasting irisin and FGF21 did not vary with temperature but the former was significantly higher in MetS-. Adjusted postprandial RQ and insulin to glucose ratios were significantly higher at 20 °C relative to 25 °C. Partial correlation analysis of differences between 27 and 20 °C indicated significant positive relationships between fasting as well as postprandial RQ and the respective changes in irisin and FGF21.
There could be an upward shift of the TNZ in MetS+, but this needs reevaluation.
背景/目的：寒冷暴露会增加产热，改善胰岛素敏感性。我们假设代谢综合征（MetS）的反应会减弱。
受试者/方法：20 名年龄在 59±10.4 岁的老年人（患有 MetS，MetS+，n=9；没有 MetS，MetS-，n=11）完成了三次 3.5 小时的随机交叉设计暴露在 20、25 和 27°C 下。在所需温度下休息一小时后，测量休息代谢率（RMR）、呼吸商（RQ）、前臂到指尖梯度（FFG）和耳部温度（IET）30 分钟。随后进行口服葡萄糖耐量试验，并继续连续测量 2 小时。采集静脉血进行临床化学、鸢尾素和成纤维细胞生长因子 21（FGF21）检测。混合模型 ANCOVA 调整了年龄、性别、体脂肪量、去脂体重和季节性数据。
存在代谢综合征×温度的显著交互作用，在 20°C 时，MetS+ 的调整后 RMR 比 MetS-高 12%，在 25°C 时高 6%，但在 27°C 时相似。FFG 随温度降低而增加，IET 随温度降低而降低，两组间程度相同。空腹鸢尾素和 FGF21 不随温度变化，但在 MetS-中显著更高。调整后的餐后 RQ 和胰岛素与葡萄糖比值在 20°C 时明显高于 25°C。27°C 和 20°C 之间差异的偏相关分析表明，空腹和餐后 RQ 与鸢尾素和 FGF21 各自的变化之间存在显著的正相关关系。
MetS+ 中的 TNZ 可能会向上转移，但这需要重新评估。
