WHO/NCD/NCS/ORH/99.1 Distribution: General Original: English
List of Contents............................................................................... i
WHO Consultation on a Standard Method for the
Determination of Fluoride Intake, Dundee, Scotland,
U.K. 4-5 July 1997 ................................................................. v
Preface...........................................................................................vii
Acknowledgements......................................................................... xi
1. Introduction..................................................................................... 1
1.1 Sources of fluoride intake in humans ........................................ 1
1.2 Fluoride metabolism and excretion............................................2
1.3 General usefulness of urinary fluoride measurements ............... 3
2. General design of study....................................................................5
2.1 Identification of study group..................................................... 5
2.2 Sampling.................................................................................... 6
2.3 Levels of monitoring.................................................................. 7
2.3.1 Methods based on time-controlled urinary collections ............. 8
2.3.2 Methods based on spot samples............................................... 11
2.4 Number of subjects.................................................................. 12
3. Methods for urine sampling and handling and evaluation
of results......................................................................................... 13
3.1 Recording of information ........................................................ 13
3.1.1 General information.................................................................. 13
3.1.2 Personal information ................................................................ 14
3.2 Collection and analysis of samples .......................................... 15
3.3 Determination of fluoride in urine .......................................... 15
3.4 General rules for tabulation and processing of data ................ 15
3.4.1 Coded recordings of personal data and individual fluoride
exposure..................................................................................... 16
3.4.2 Standard table for level F24h................................................... 16
3.4.3 Standard table for level Fl6h, incomplete series..................... 19
3.4.4 Standard table for level Fl6h, complete series........................21
3.4.5 Standard table for level F8h and special cases.........................21
3.4.6 Standard table for level F/creat.................................................21
3.4.7 Standard table for level F-conc.................................................22
3.5 Cleaning of data ...................................................................... 22
3.6 24-hour extrapolations ............................................................24
3.6.1 Extrapolations from F16h data................................................ 24
3.6.2 Extrapolations from F8h data.................................................. 28
3.6.3 Extrapolations from F/creat data ............................................. 29
3.6.4 Extrapolations from F-conc data.............................................. 29
3.7 WHO support for tabulation and analysis of data .................. 30
4 Design of the final report ...............................................................31
4.1 Text .....................................................................................31
4.2 Results, tables, graphs, discussion........................................... 32
4.3 Summary and conclusions....................................................... 33
Tables...................................................................................................... 34
Table 1 Urinary fluoride data, summary............................................ 34
Table 2 Five levels of assessing urinary fluoride as a measure
of fluoride intake................................................................... 35
Table 3 Summary of urine data from 40 children aged 4-6 years
in Staryi Oscol (given 180 nil of milk, containing 5.0 ppm fluoride, at 12.00 daily for 5 days) during the third test period 17-18 February 1994.................................................. 36
Table 4 Cleaning criteria at various ages and for various levels of
fluoride exposure................................................................... 37
Table 5 Provisional standards for urinary fluoride excretion and
concentrations....................................................................... 38
Figures ..............................................................................................39
Figure 1 Fluoride excretion per hour as determined from consecutive (spontaneous) micturitions. Such diagrams can be automatically constructed from the corresponding spreadsheet table................................................................... 39
Figure 2 Graphical representation of the example (David Morris) used for illustrating the IDUFE-extrapolation, data in chapter 3.3. Dark horizontal lines: excretion measured during the number of hours as represented in the diagram. Punctuated lines:
extrapolated hours completing the 4-8-12-hour IDUFE-model for estimating 24-hour fluoride excretion.............................. 40
Figure 3 Illustration of the IDUFE-extrapolation using the average fluoride excretion shown in Table 3 (for types of lines see legend to Figure 2) ................................................................41
Figure 4 Fluoride excretion per hour as determined in the period LOW, HI and NOC, based on the averages in each of the three periods shown in Table A.2 extrapolation pattern IDUFE (for type of lines see legend to Figure 2) ...................42
Figure 5 Illustration based on the same excretion averages as Figure 4; however, an extrapolation pattern adapted to the actual lifestyle of the children (6 hours LO, 5 hours HI, 13 hours NOC) was used, considering that many children had two periods of high excretion, one in the early afternoon and a shorter one after dinner (for type of lines see legend to Figure 2), which is a realistic time-table for meals of Swiss children...................................43
Annex ............................................................................................45
1.1 Collection and analysis of samples........................................ 45
1.2 Time-controlled urine sampling for complete collections...... 45
1.3 Recording of information ......................................................47
1.4 Collection of urine at night ...................................................49
1.5 Determination of fluoride in urine and water .......................49
1.6 Required equipment and solutions........................................50
1.7 Analysis Check-List ...............................................................51
1.8 Combination fluoride electrode preparation and checking
electrode operation................................................................ 51
1.9 Direct calibration and determination of fluoride
concentration in urine samples .............................................52
1.10 Processing results ..................................................................53
1.11 Standard table for level F24h ................................................ 54
1.12 Standard table for level F16, incomplete series .....................55
1.13 24-hour Extrapolations.......................................................... 58
1.14 WHO support for tabulation and analysis of data ................ 5 9
Tables......................................................................................................62
Table Al Level 24h: data and computing table for 24 hour continuous
collections, example with 6 cases ..........................................62
Table A2 Dataset example and computing table for level F16,
3 collections, incomplete series .............................................63
Table A3 Ideal format of a dataset to be transferred to an evaluation
center.....................................................................................64
Figures..................................................................................................... 65
Figure A. 1 Design and use of label to be attached to urine
collecting jar..........................................................................65
Figure A.2 Example of record of urine collection.................................... 66
Figure A. 3 Example of a completed label attached to urine
collecting jar.......................................................................... 6 7
Figure A.4 Overnight urine collection label ............................................68
References......................................................................................69