The present study examines whether the daily rhythm of distal skin temperature (DST) is associated with brown adipose tissue (BAT) metabolism as determined by 18F-fluorodeoxyglucose (18F-FDG) uptake in young adults. Using a wireless thermometer (iButton) worn on the nondominant wrist, DST was measured in 77 subjects (26% male; age 22 ± 2 years; body mass index 25.2 ± 4.8 kg/m2) for 7 consecutive days. The temperatures to which they were habitually exposed over the day were also recorded. The interday stability of DST was calculated from the collected data, along with the intraday variability and relative amplitude; the mean temperature of the 5 and 10 consecutive hours with the maximum and minimum DST values, respectively; and when these hours occurred. Following exposure to cold, BAT volume and mean and peak standardized 18F-FDG uptake (SUVmean and SUVpeak) were determined for each subject via static 18F-FDG positron emission tomography/computed tomography scanning. Relative amplitude and the time at which the 10 consecutive hours of minimum DST values occurred were positively associated with BAT volume, SUVmean, and SUVpeak (p ≤ 0.02), whereas the mean DST of that period was inversely associated with the latter BAT variables (p ≤ 0.01). The interday stability and intraday variability of the DST were also associated (directly and inversely, respectively) with BAT SUVpeak (p ≤ 0.02 for both). All of these associations disappeared, however, when the analyses were adjusted for the ambient temperature to which the subjects were habitually exposed. Thus, the relationship between the daily rhythm of DST and BAT activity estimated by 18F-FDG uptake is masked by environmental and likely behavioral factors. Of note is that those participants exposed to the lowest ambient temperature showed 3 to 5 times more BAT volume and activity compared with subjects who were exposed to a warmer ambient temperature.

中文翻译：

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久坐的年轻成年人的每日皮肤温度的节律与棕色脂肪组织18F-FDG摄取之间的关系。

本研究检查年轻人的远端皮肤温度（DST）的每日节律是否与棕色脂肪组织（BAT）代谢有关，如通过18F-氟脱氧葡萄糖（18F-FDG）摄取确定的那样。使用佩戴在非主要手腕上的无线温度计（iButton），连续7天对77位受试者（26％男性；年龄22±2岁；体重指数25.2±4.8 kg / m2）进行了DST测量。还记录了他们一天中习惯暴露的温度。根据收集的数据计算出夏令时的日间稳定性，以及日内波动性和相对振幅；连续5个小时和10个小时的平均温度，分别具有最大和最小DST值；以及这些时间何时发生。暴露于寒冷之后 通过静态18F-FDG正电子发射断层扫描/计算机断层扫描，确定每位受试者的BAT量以及均值和峰值标准化18F-FDG摄取量（SUVmean和SUVpeak）。相对振幅和连续10个小时达到最低DST值的时间与BAT量，SUVmean和SUVpeak正相关（p≤0.02），而该时期的平均DST与后面的BAT变量成反比（p ≤0.01）。DST的日间稳定性和日内变异性也分别与BAT SUVpeak相关（分别为正向和反向）（两者均p≤0.02）。但是，当针对受试者习惯暴露的环境温度进行分析调整后，所有这些关联都消失了。从而，环境和可能的行为因素掩盖了DST的每日节律与通过18F-FDG摄取估算的BAT活动之间的关系。值得注意的是，暴露于最低环境温度下的那些参与者所表现出的BAT体积和活性是暴露于温暖的环境下的受试者的3-5倍。