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Determining an Upper Reference Value for the Urinary Fluoride-Creatinine Ratio in Healthy Children Younger than 7 Years

Lookup NU author(s): Dr Vida Zohoori, Emerita Professor Anne Maguire



This is the authors' accepted manuscript of an article that has been published in its final definitive form by S. Karger AG, 2017.

For re-use rights please refer to the publisher's terms and conditions.


© 2017 S. Karger AG, Basel 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.

Publication metadata

Author(s): Zohoori FV, Maguire A

Publication type: Article

Publication status: Published

Journal: Caries Research

Year: 2017

Volume: 51

Pages: 283-289

Print publication date: 01/08/2017

Online publication date: 24/05/2017

Acceptance date: 21/03/2017

Date deposited: 17/08/2017

ISSN (print): 0008-6568

ISSN (electronic): 1421-976X

Publisher: S. Karger AG


DOI: 10.1159/000472263


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