This full text version, available on TeesRep, is the final version of this PhD Thesis: Omid, N. (2012) The assessment level of fluoride intake/exposure using “3-day dietary diary” & “2-day duplicate” methods. Unpublished PhD thesis. Teesside University. This document was downloaded from http://tees.openrepository.com/tees/handle/10149/251437 All items in TeesRep are protected by copyright, with all rights reserved, unless otherwise indicated. TeesRep: Teesside University's Research Repository http://tees.openrepository.com/tees/ The Assessment Level of Fluoride Intake/Exposure using “3-Day Dietary Diary” & “2-Day Duplicate” methods N. Omid PhD December 2011 Preface Declaration I hereby declare that the work presented in this thesis is entirely my own and that, to the best of my knowledge, has never been published or presented for the award of any other degree or diploma of the university or other institute of higher education. i Preface Acknowledgements I would like to express my sincere appreciation to all of those who made this work possible. First to the Director of the study Dr Vida Zohoori for her endless support, superb guidance and constant encouragement at all times. I am also indebted to my 2nd supervisor Professor Alan Batterham for his expertise and advice in statistical analysis, to the 3rd supervisor Dr Liam O’Hare and project advisor Dr Anne Maguire for their advice and support. I would like to acknowledge the kind advice of Dr Rulph Duckworth for fluoride analysis of toothpaste samples. I am most grateful to Professor Janet Schuksmith, for her support during the course of this study, staff and colleagues at the Institute of Health and Social Care, Teesside University, Mrs Lesley Watson, Claire Gee, Elizabeth Harwood, Rebekah McNaughton for their tireless administrative and assistance. I am most grateful to parents and their children for their participation without whose co-operation the study would have not been carried out. I would like to acknowledge the assistance of Mrs Gill Wheater from James Cook University Hospital, Middlesbrough and Mr Darren Wardell from Newtec laboratory, Billingham, for carrying out part of the sample analysis. I am most grateful to my parents for their endless encouragement, to my friends for their support and patience. I would like to extend my deepest gratitude to my husband, my son and my daughter for unending patience, love and endurance without whom this work would have not been possible. Acknowledgement is due to the Borrow Foundation for partially funding this project. Finally, my thanks to the University of Teesside for providing this opportunity for me. ii Preface Table of Contents Declaration ....................................................................................................... i Acknowledgements ......................................................................................... ii Table of Contents .......................................................................................... iii List of Tables ................................................................................................... x List of Figures .............................................................................................. xvi List of Appendices .................................................................................... xviii Abstract ........................................................................................................ xix Chapter 1 Introduction ............................................................................ 1 1.1. Fluoride and environment ................................................................................... 1 1.2. Fluoride metabolism ............................................................................................ 2 1.2.1. Fluoride ingestion and absorption ................................................................ 2 1.2.2. Fluoride distribution ..................................................................................... 2 1.2.3. Fluoride excretion ......................................................................................... 3 1.3. Fluoride and oral health....................................................................................... 4 1.4. Fluoride and dental fluorosis ............................................................................... 5 1.5. Fluoride balance .................................................................................................. 5 1.6. Scope of the thesis ............................................................................................... 6 1.7. Thesis outline ...................................................................................................... 6 Chapter 2 Literature review .................................................................... 7 2.1. Introduction ......................................................................................................... 7 2.2. Dietary assessment methods................................................................................ 7 2.2.1. Prospective methods ..................................................................................... 7 2.2.2. Retrospective methods .................................................................................. 9 2.2.3. Methods used for the assessment of fluoride intake ................................... 12 2.3. Validation of completeness of 24-h urine collections ....................................... 13 2.3.1. External markers ......................................................................................... 13 2.3.2. Internal markers .......................................................................................... 14 2.4. Validation of Dietary Assessment Methods ...................................................... 18 2.4.1. Energy intake (EI) and Physical Activity Level (PAL) .............................. 19 2.4.2. Twenty-four hour urine nitrogen ................................................................ 21 2.4.2.1. Nitrogen (protein) function and requirement ...................................... 21 iii Preface 2.4.2.2. Studies of nitrogen intake and excretion ............................................. 21 2.4.3. Twenty-four hour urine potassium ............................................................. 24 2.4.3.1. Potassium function and requirement ................................................... 24 2.4.3.2. Renal handling of potassium ............................................................... 25 2.4.3.3. Studies of potassium intake and excretion .......................................... 26 2.5. Fluoride analytical methods .............................................................................. 27 2.6. Fluoride intake studies ...................................................................................... 29 2.6.1. Fluoride intake from diet ............................................................................ 33 2.6.2. Fluoride intake from toothpaste .................................................................. 34 2.6.3. Total fluoride intake ................................................................................... 36 2.6.4. Incidence of dental fluorosis in fluoridated and no-fluoridated areas ........ 37 2.7. Fluoride excretion studies ................................................................................. 38 2.8. Fluoride intake/excretion studies ...................................................................... 42 2.9. Summary and conclusion .................................................................................. 43 Chapter 3 Aim ......................................................................................... 46 3.1. Main Aim .......................................................................................................... 46 3.2. Subsidiary aims ................................................................................................. 46 Chapter 4 Pilot investigation on development of an analytical method for measurement of fluoride in expectorated saliva/toothpaste ......... 47 4.1. Introduction ....................................................................................................... 47 4.2. Aims .................................................................................................................. 49 4.3. Materials and methods ...................................................................................... 49 4.3.1. Preparation and analysis of toothpaste samples ......................................... 49 4.3.2. Preparation and analysis of expectorated saliva, toothpaste and rinse ....... 49 4.4. Results ............................................................................................................... 52 4.5. Discussion ......................................................................................................... 56 4.5.1. Toothpastes ................................................................................................. 56 4.5.2. Expectorated saliva, toothpaste and rinse ................................................... 57 4.6. Conclusion ......................................................................................................... 57 Chapter 5 General materials and methods .......................................... 59 5.1. Introduction ....................................................................................................... 59 5.2. Materials and Methods .....................................................................................