Estimation of non-shivering thermogenesis and cold-induced nutrient oxidation rates: Impact of method for data selection and analysis. Issue 5 (October 2019)

• Record Type: Journal Article
• Authors: Sanchez-Delgado, Guillermo; Alcantara, Juan M.A.; Acosta, Francisco M.; Martinez-Tellez, Borja; Amaro-Gahete, Francisco J.; Ortiz-Alvarez, Lourdes; Löf, Marie; Labayen, Idoia; Ruiz, Jonatan R.
• Is Part Of: Clinical nutrition. Volume 38:Issue 5(2019)
• Page Start: 2168
• Page End: 2174
• Publication Date: 2019-10
• Subjects: Cold-induced thermogenesis -- Adaptive thermogenesis -- Indirect calorimetry -- Metabolic rate -- Energy balance -- Obesity; BAT Brown adipose tissue -- CIT Cold-induced thermogenesis -- RMR Resting metabolic Rate -- SS Steady state -- TI Time interval -- EE Energy expenditure -- AUC Area under the curve -- CCM CCM Express (Medgraphics Corp, Minnesota, USA) -- MGU Ultima CardiO2 (Medgraphics Corp, Minnesota, USA) -- DXA Dual X-ray absorciometry -- RER Respiratory exchange ratio -- CHOox Carbohydrates oxidation -- FATox Fat oxidation -- ANOVA Analyses of variance -- 5min-TI mean values of every consecutive 5-min period -- 5min-SS-4P The most stable 5-min period of every forth part of the cold exposure -- 5min-SS-2P The most stable 5-min period of every half part of the cold exposure; Critically ill -- Nutrition -- Periodicals; Diet therapy -- Periodicals; Parenteral feeding -- Periodicals; Enteral feeding -- Periodicals; Enteral Nutrition -- Periodicals; Parenteral Nutrition -- Periodicals; Metabolism -- Periodicals; Diétothérapie -- Périodiques; Alimentation parentérale -- Périodiques; Alimentation entérale -- Périodiques; Nutrition -- Périodiques; Diet therapy; Enteral feeding; Nutrition; Parenteral feeding; Electronic journals; Periodicals; Electronic journals; 615.854
• DOI: 10.1016/j.clnu.2018.09.009
• Languages: English
• ISSNs: 0261-5614

Abstract

Summary: Background & aims: Since the discovery of active brown adipose tissue in human adults, non-shivering cold-induced thermogenesis (CIT) has been regarded as a promising tool to combat obesity. However, there is a lack of consensus regarding the method of choice to analyze indirect calorimetry data from a CIT study. We analyzed the impact of methods for data selection and methods for data analysis on measures of cold-induced energy expenditure (EE) and nutrient oxidation rates. Methods: Forty-four young healthy adults (22.1 ± 2.1 years old, 25.6 ± 5.2 kg/m 2, 29 women) participated in the study. Resting metabolic rate (RMR), cold-induced thermogenesis (CIT), and cold-induced nutrient oxidation rates were estimated by indirect calorimetry under fasting conditions during 1 h of cold exposure combining air conditioning (19.5–20 °C) and a water perfused cooling vest set at a temperature of 4 °C above the individual shivering threshold. We applied three methods for data selection: (i) time intervals every 5 min (5min -TI ), (ii) the most stable 5-min period of every forth part of the cold exposure (5min -SS-4P ), and (iii) the most stable 5-min period of every half part of the cold exposure (5min -SS-2P ). Lately we applied two methods for data analysis: (i) area under the curve as a percentage of the baseline RMR (AUC) and; (ii) the difference between EE at the end of the cold exposure and baseline RMR (Last-RMR). Results: Mean overall CIT estimation ranged from 11.6 ± 10.0 to 20.1 ± 17.2 %RMR depending on the methods for data selection and analysis used. Regarding methods for data selection, 5min -SS-2P did not allow to observe physiologically relevant phenomena (e.g. metabolic shift in fuel oxidation; P = 0.547) due to a lack of resolution. The 5min -TI and 5min -SS-4P methods for data selection seemed to be accurate enough to observe physiologically relevant phenomena (all P < 0.014), but not comparable for estimating over-all CIT and cold-induced nutrient oxidation rates (P < 0.01). Regarding methods for data analysis, the AUC seemed to be less affected for data artefacts and to be more representative in participants with a non-stable energy expenditure during cold exposure. Conclusions: The methods for data selection and analysis can have a profound impact on CIT and cold-induced nutrient oxidation rates estimations, and therefore, it is mandatory to unify it across scientific community to allow inter-study comparisons. Based on our findings, 5min -TI should be considered the method of choice to study dynamics (i.e. changes across time) of CIT and cold-induced nutrient oxidation rates, while 5min -SS-4P and AUC should be the method of choice when computing CIT and cold-induced nutrient oxidation rates as a single value.