Balogun Kayode A, Zuromski Lauren M, Kim Rachel, Anderson Austin, Lozier Bucky, Kish-Trier Erik, Yuzyuk Tatiana
Department of Pathology, University of Utah, Salt Lake City, UT, United States; ARUP Laboratories, Salt Lake City, UT, United States.
ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT, United States.
Clin Biochem. 2021 Nov;97:25-33. doi: 10.1016/j.clinbiochem.2021.07.013. Epub 2021 Jul 27.
The current assessment of nutritional status and diagnosis of essential fatty acids deficiency (EFAD) utilizes the analysis of long-chain fatty acids (LCFAs) in serum or plasma; however, these concentrations do not represent habitual LCFA intake. LCFAs in red blood cells (RBCs) are less prone to intra-individual variability and exclude the need for fasting, which is unrealistic in pediatric populations. Our study objective was to characterize the RBC LCFA profiles in pediatric and adult reference populations and establish age-specific reference intervals (RIs).
Twenty-one LCFAs in RBCs were measured in 523 pediatric and adult controls by gas chromatography-mass spectrometry. Model-based clustering was used to identify possible age subgroups. After removing outliers by the Tukey method, initial age subgroups were then compared using the Harris-Boyd method in an iterative manner. RIs (95%), with confidence intervals (90%), in the final age groups were established using parametric or non-parametric statistics.
Our data showed heterogeneous changes in the concentrations of most LCFAs and the EFAD biomarkers (mead acid, Triene/Tetraene ratio) during infancy. Model-based clustering identified six initial age subgroups per fatty acid, on average. Our application of the iterative Harris-Boyd method decreased the average number of age groups to three per fatty acid, with 13 total unique age cut-offs. Finally, using these age groups, we established age-specific RIs for 21 fatty acids, six group totals, and the Triene/Tetraene ratio.
Our study revealed significant age-dependent changes in RBC fatty acid profiles warranting separate pediatric and adults RIs. Model-based clustering and the iterative application of the Harris-Boyd method were successfully used to establish RBC fatty acid RIs for an objective assessment of long-term nutritional status in pediatric and adult populations.
目前对营养状况的评估以及必需脂肪酸缺乏症（EFAD）的诊断采用血清或血浆中长链脂肪酸（LCFA）的分析；然而，这些浓度并不代表习惯性的LCFA摄入量。红细胞（RBC）中的LCFA个体内变异性较小，且无需空腹检测，这在儿科人群中是不现实的。我们的研究目的是描述儿科和成人参考人群的红细胞LCFA谱，并建立特定年龄的参考区间（RI）。
采用气相色谱 - 质谱法测定了523名儿科和成人对照者红细胞中的21种LCFA。基于模型的聚类用于识别可能的年龄亚组。通过Tukey方法去除异常值后，然后使用Harris - Boyd方法以迭代方式比较初始年龄亚组。使用参数或非参数统计方法在最终年龄组中建立具有90%置信区间的95% RI。
我们的数据显示，在婴儿期，大多数LCFA和EFAD生物标志物（二十四碳三烯酸、三烯/四烯比值）的浓度存在异质性变化。基于模型的聚类平均每个脂肪酸识别出六个初始年龄亚组。我们对迭代Harris - Boyd方法的应用将每个脂肪酸的平均年龄组数量减少到三个，共有13个独特的年龄分界点。最后，使用这些年龄组，我们建立了21种脂肪酸、六个组总和以及三烯/四烯比值的特定年龄RI。
我们的研究揭示了红细胞脂肪酸谱存在显著的年龄依赖性变化，需要分别为儿科和成人建立RI。基于模型的聚类和Harris - Boyd方法的迭代应用成功用于建立红细胞脂肪酸RI，以客观评估儿科和成人人群的长期营养状况。
