Lot 2 – Task 2 Related Activities • Report of the Forum on Water Fluoridation (www.fluoridationforum.ie). • Project Flint: Fluoride Intake from Toothpaste (Ketley, O’Mullane and Holbrook (2004), Community Dentistry and Oral Epidemiology, Suppl 1, 32, 1-76). - methods of recording fluoride ingestion from toothpaste - development of a standardised photographic method for recording dental fluorosis Funded under the EU Biomed 2 Project Lot 2 – Task 2 Development of standard internationally agreed fluoride analytical methods A review of literature and discussions with other researchers indicated that there was considerable variation in the methods used to analyse fluoride levels in body fluid/tissues and food/beverages. International collaboration should be initiated “to develop simple global gold standard methods” for fluoride analysis of different sample types. Develop international consensus on methods for collection, storage and laboratory procedures” (Clarkson J et al, 2000, International Collaborative Research on Fluoride, J Dent Res 79; 893-904). Lot 2 – Task 2 Development of standard internationally agreed fluoride analytical methods Indiana, U.S. (Stookey) Campinas, Brazil (Cury) Iowa U.S. (Levy) Loma Linda, U.S. (Li) Newcastle, U.K. (Maguire) Barcelona, Spain (Margineda) Thammasat, Thailand (Phantumvanit) Chile (Villa) Cork, Ireland (O’Mullane) Georgia, U.S. (Whitford) Supported by NIDCR grant R21 DE 14716-1 Lot 2 – Task 2 Development of standard internationally agreed fluoride analytical methods Hard Tissue Saliva Urine Plasma Food Homogenate Beverages Lot 2 – Task 2 Development of standard internationally agreed fluoride analytical methods Analysis of reference materials is now complete. The final phase requiring the analysis of the different samples in all participating laboratories is currently in progress. “All participating laboratories were able to obtain precise and true results, as defined by the ISO, using an agreed upon standard operation procedure” (Martinez-Mier et al, 2003) Martinez-Mier et al, Caries Research (ORCA Abstracts 2003, 2004, 2004 and 2005). Lot 2 – Task 2 Use of fingernail clippings to monitor fluoride ingestion The development of a reliable and accessible biomarker for monitoring the amount of fluoride ingested and absorbed is now regarded as a priority (see Clarkson, International Fluoride Collaboration). In 1999, Whitford (Caries Res. 1999; 33:462-467) suggested that fluoride levels in fingernail clippings could provide a reliable, inert and non-invasive marker of the amount of fluoride ingested prior to clipping. The OHSRC has collaborated with Dr Whitford and his team in further developing this idea. To begin with, the method of analysis of fingernail clippings to be used by Dr Whitford’s group in Augusta, Georgia, USA and Ms Eileen MacSweeney, Head of the OHSRC Laboratory in Cork was agreed. Lot 2 – Task 2 Use of fingernail clippings to monitor fluoride ingestion Pilot Study Samples of children in Bangor Co. Down, Northern Ireland (fluoride levels in drinking water <0.2ppm) and in Cork City (fluoride levels 0.9ppm) were included in the study. Children aged 2-3 were chosen because they are thought to be most at risk of developing enamel fluorosis in their maxillary permanent incisors at this age. Mc Donnell, S.T, O Mullane, D, Cronin, M, Mac Cormac C, Kirk J. Community Dental Health 2004; 21:19-24. (Funded by HRB) Lot 2 – Task 2 Use of fingernail clippings to monitor fluoride ingestion Fluoridation Status Full Non Total n 25 25 50 Age mean 30.2 29.3 29.7 (months) Fl Conc mean 3.21 1.71 2.46 Lot 2 – Task 2 Selecting best field method for recording dietary intake in 2-3 year old children 2 methods have been used: Three-Day Diary In this method the participant was asked to weigh and record, at the time of consumption, all foods and beverages over a three day period. Each individual food/beverage was then purchased by OHSRC, homogenized and tested for total fluoride content. - F content of each food/beverage item established Duplicate Portion This method involved the duplication, by the parent/guardian, of all foods and beverages consumed over three days. The daily dietary items are mixed together, homogenized and analyzed. - Total F intake for each day obtained; contribution of each food/beverage item not established. Lot 2 – Task 2 Selecting best method for recording dietary intake in 2- 3 year old children. Pilot Study The parents/guardians of 2 to 3 year old children undertook both Three-Day Diary and Duplicate Diet Methods. Conclusion In order to get an initial assessment of fluoride ingested by 2 to 3 year old children in Ireland, the Duplicate Diet method is the most practical approach. There is less laboratory time and the costs are also reduced. In the event of the results indicating high fluoride intake, then a follow up study using the 3 day diary method can be conducted in order to determine which food/beverage item is contributing to the raised fluoride level in the diet. Lot 2 – Task 2 Pilot Study - Daily fluoride intake of 2-3 year old children using duplicate portion method (mg) SUBJECT IDENTITY MEAN RANGE 202 FROM SOLIDS (mg) 0.04 0.03 -0.05 FROM LIQUIDS (mg) 1.27 0.87 - 1.67 DIETARY FLUORIDE INTAKE 1.31 0.91 - 1.71 WEIGHT OF SUBJECT (Kg) 15.00 AVERAGE FLUORIDE INTAKE (mg/Kg/day) 0.09 - 204 FROM SOLIDS (mg) 0.014 0.009 - 0.011 FROM LIQUIDS (mg) 0.014 0 DIETARY FLUORIDE INTAKE 0.029 0.028 - 0.030 WEIGHT OF SUBJECT (Kg) 12.500 AVERAGE FLUORIDE INTAKE (mg/Kg/day) 0.002 - Lot 2 – Task 2 Pilot Study - Daily fluoride intake of 2-3 year old children using duplicate portion method (mg) 103 FROM SOLIDS (mg) 0.09 0.08 - 0.1 FROM LIQUIDS (mg) 0.20 0.16 - 0.24 DIETARY FLUORIDE INTAKE 0.29 0.24 - 0.34 WEIGHT OF SUBJECT (Kg) 13.50 AVERAGE FLUORIDE INTAKE (mg/Kg/day) 0.02 - 105 FROM SOLIDS (mg) 0.09 0.07 - 0.11 FROM LIQUIDS (mg) 0.22 0.19 - 0.25 DIETARY FLUORIDE INTAKE 0.31 0.26 - 0.36 WEIGHT OF SUBJECT (Kg) 16.00 AVERAGE FLUORIDE INTAKE (mg/Kg/day) 0.02 - Lot 2 – Task 2 For children under 8 years of age (i.e. those at risk of developing dental fluorosis), it is accepted that the daily intake of fluoride which will not produce mild fluorosis in permanent teeth is 0.05 mg F/kg body weight/day, with a range of 0.02 to 0.1 mg F/kg/day. The lowest observed adverse effect level (LOAEL) is 0.1 mg F/kg/day. (www.fluoridationforum.ie) Lot 2 - Task 3 Association between fluoridation of water supplies and the incidence of fracture of the neck of femur There is consensus that in order to attain adequate sample sizes to show differences in fracture rates between fluoridated and non- fluoridated areas multi-centre studies are required. Lot 2 - Task 3 Association between fluoridation of water supplies and the incidence of fracture of the neck of femur The OHSRC in collaboration with the Departments of Public Health and Epidemiology in UCC and QUB, have developed a protocol to measure the incidence of fracture of the neck of the femur amongst adults aged 50 years and older in NI and RoI. Information Sources The Directorate of Information Systems (DIS) of the Department of Health and Social Services and Public Safety in Northern Ireland (DHSSPSNI) annually collates computerised hospital admission data [Patient Administration System (PAS)]. The HIPE database in RoI is a computer-based information system designed to record episodes of care in acute hospitals in Ireland. Ongoing Related Projects in OHSRC Include; * The Limerick/Derry Study The relationship between fluoride levels in saliva, toothpaste use and the incidence of dental caries. Funded by industry and HRB. PhD Fellow Rose Kingston. * The Benefits and Risks of Water Fluoridation Four year research programme funded by HRB. PhD Fellows Deirdre Browne, (Dental Caries and Dental Fluorosis) Edel Flannery, (Statistics) Tara Crowley, (Psychology) Ongoing Related Projects in OHSRC Include; * The Dublin/Belfast Study “Winning Smiles” Toothpaste Use Evaluation. Funded by Dental Health Foundation and Queens University, Belfast. Concluding Comments The contribution of the User Group to the successful conclusion of the Lot 2 Project is acknowledged. As recommended in the Forum Report, the “New and Emerging Issues” Sub-Committee of the Irish Expert Body on Fluorides and Health is considering research priorities. The daily intake of fluoride in different population groups is recognised as a major research priority by a number of international agencies. Under Lot 2, the OHSRC in collaboration with its international partners and the User Group has developed techniques and technologies to answer a wide range of research questions.
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