BACKGROUND Human scalp hair is a valuable matrix for determining long-term cortisol concentrations, with wide-spread applicability in clinical care as well as research. However, pediatric reference intervals are lacking. The aim of this cross-sectional study is to establish age-adjusted reference intervals for hair cortisol in children and to gain insight into hair growth velocity in children up to 2 years old. METHODS A total of 625 healthy children were enrolled through recruitment in pregnancy, infant-welfare clinics, and school visits. Scalp hair cortisol levels were measured using liquid chromatography-tandem mass spectrometry. Age-adjusted reference intervals were established in children from birth to 18 years old. Hair growth velocity was determined in children 0-2 years of age by measuring hair length at 4- to 10-week intervals. RESULTS Hair cortisol levels were high (162.4 pg/mg, 2.5th-97.5th percentile: 28.8-961) after birth with a sharp fall in the first 3 months of life. This is followed by lower values until age 6 and then by graduated and subtle higher values to adult concentrations are reached at the age of 18 years (3.0 pg/mg, 2.5th-97.5th percentile: 0.53-17.8). Average hair growth velocity measured in mm/month was significantly lower in infants 0-6 months of age compared to children 12-24 months (3.5 versus 9.4, P < 0.001). CONCLUSIONS This is the first study to provide age-adjusted reference intervals for hair cortisol in children from 0-18 years. Higher hair cortisol concentrations in infants might be explained by the significantly lower hair growth rate in the first year of life. The establishment of pediatric hair cortisol reference ranges broadens the potential applications of this biomarker in pediatric clinical care.

中文翻译：

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基于 LC-MS/MS 的健康儿童头发皮质醇参考区间

背景人类头皮毛发是用于确定长期皮质醇浓度的有价值的基质，在临床护理和研究中具有广泛的适用性。然而，缺乏儿科参考区间。这项横断面研究的目的是建立儿童头发皮质醇的年龄调整参考区间，并深入了解 2 岁以下儿童的头发生长速度。方法通过孕期招募、婴幼儿福利门诊、学校访学等方式，共招募625名健康儿童。使用液相色谱-串联质谱法测量头皮毛发皮质醇水平。在从出生到 18 岁的儿童中建立了年龄调整参考区间。通过每隔 4 至 10 周测量头发长度，确定 0 至 2 岁儿童的头发生长速度。结果 出生后头发皮质醇水平很高（162.4 pg/mg，第 2.5-97.5 个百分位数：28.8-961），在生命的前 3 个月急剧下降。随后是较低的值，直到 6 岁，然后逐渐增加，并在 18 岁时达到成人浓度的微妙较高值（3.0 pg/mg，第 2.5-97.5 个百分位：0.53-17.8）。与 12-24 个月大的儿童相比，0-6 个月大的婴儿的平均毛发生长速度（以毫米/月为单位）显着降低（3.5 对 9.4，P < 0.001）。结论 这是第一项为 0-18 岁儿童头发皮质醇提供年龄调整参考区间的研究。婴儿头发皮质醇浓度较高的原因可能是出生后第一年的头发生长速度显着降低。