School of Health and Social Care, Teesside University, Middlesbrough, UK.
Caries Res. 2017;51(4):283-289. doi: 10.1159/000472263. Epub 2017 May 24.
The urinary fluoride/creatinine ratio (UF/Cr) in a spot urine sample could be a useful systemic F exposure monitoring tool. No reference value for UF/Cr currently exists, therefore this study aimed to establish an upper reference value for a UF/Cr, corresponding to excessive systemic F exposure, i.e., >0.07 mg F/kg body weight (b.w.)/day, in children. Subsidiary aims were to examine the relationship between (i) total daily F intake (TDFI) and 24-h urinary F excretion (DUFE); (ii) DUFE and UF/Cr, and (iii) TDFI and UF/Cr. Simultaneously collected TDFI, DUFE, and urinary creatinine (UCr) data in children <7 years were taken from UK studies conducted from 2002 to 2014 in order to calculate UF/Cr (mg/g) for each child. For the 158 children (mean age 5.8 years) included in the data analysis, mean TDFI and DUFE were 0.049 (SD 0.033) and 0.016 (SD 0.008) mg/kg b.w./day, respectively, and the mean UF/Cr was 1.21 (SD 0.61) mg/g. Significant (p < 0.001) positive linear correlations were found between TDFI and DUFE, DUFE and UF/Cr, and TDFI and UF/Cr. The estimated upper reference value for UF/Cr was 1.69 mg/g; this was significantly (p = 0.019) higher than the UF/Cr (1.29) associated with optimal F exposure (0.05-0.07 mg/kg b.w./day). In conclusion, the strong positive correlation between TDFI and UF/Cr confirms the strong association of these 2 F exposure variables and the value of a spot urine sample for prediction of TDFI (i.e., the most important risk factor in determining fluorosis occurrence and severity) in young children. Establishing an estimation of an upper reference value of 1.69 mg/g for UF/Cr in spot urine samples could simplify and facilitate their use as a valuable tool in large epidemiological studies.
尿氟/肌酐比值（UF/Cr）在单次尿样中可作为一种有用的全身氟暴露监测工具。目前尚不存在 UF/Cr 的参考值，因此本研究旨在建立一个 UF/Cr 的上限参考值，对应于儿童的过量全身氟暴露，即 >0.07mg F/kg 体重/天。次要目的是检验（i）总日氟摄入量（TDFI）与 24 小时尿氟排泄量（DUFE）之间的关系；（ii）DUFE 与 UF/Cr 之间的关系；以及（iii）TDFI 与 UF/Cr 之间的关系。为了计算每个儿童的 UF/Cr（mg/g），从 2002 年至 2014 年在英国进行的研究中，同时收集了 7 岁以下儿童的 TDFI、DUFE 和尿肌酐（UCr）数据。在数据分析中，纳入了 158 名儿童（平均年龄 5.8 岁），其 TDFI 和 DUFE 的平均值分别为 0.049（SD 0.033）和 0.016（SD 0.008）mg/kg 体重/天，UF/Cr 的平均值为 1.21（SD 0.61）mg/g。TDFI 与 DUFE、DUFE 与 UF/Cr 以及 TDFI 与 UF/Cr 之间均呈显著的（p<0.001）正线性相关。估计的 UF/Cr 上限参考值为 1.69mg/g；与最佳氟暴露（0.05-0.07mg/kg 体重/天）相关的 UF/Cr（1.29）相比，这一值显著升高（p=0.019）。总之，TDFI 与 UF/Cr 之间的强正相关证实了这两个氟暴露变量之间的强烈关联，以及单次尿样对预测 TDFI（即决定氟中毒发生和严重程度的最重要危险因素）的价值。建立 1.69mg/g 作为单次尿样 UF/Cr 的上限参考值，可以简化并促进其在大型流行病学研究中作为有价值工具的使用。
