Fluorosis in Tanzania Biomarkers research symposium 8 May 2012 Professor Richard Walker Consultant Physician and Honorary Professor of Ageing and International Health
Where is the Hai District? Hai District Dodoma Dar es Salaam
Screening questions for stroke prevalence study Is there anyone in the household with a history of stroke? Is there anyone in the household with a weakness down one side of the body? Does anyone in the household require assistance with: a) dressing?, b) eating?, c) toileting?
Investigations
Blood results Vitamin D normal Raised ALP Low serum calcium (lowest corrected = 1.34mmol/L)
X-rays
X-rays Osteoporotic areas Osteomalacic areas with looser s zones No calcification of ligaments
Well water analyses Fluoride levels in excess of 20ppm
Fluoride Drinking Water Standards Water Standards WHO 1.5ppm Tanzania 8ppm
Resolution Rundugai 1995 Dental & Skeletal Fluorosis Wells found to be high in fluoride Wells closed, piped water provided No new cases reported
Water supply
Northern Hai High Rainfall The Hai District Drinking Water Sources predominantly surface water (streams, natural springs)
Southern Hai Low Rainfall The Hai District Drinking Water Sources predominantly groundwater (wells, boreholes)
Fluoride Fluoride Naturally occurring at some level in nearly all waters Added in the developed world due to potential dental health benefits Consumption of high levels of fluoride lead to skeletal fluorosis and dental fluorosis
Skeletal Fluorosis Bone Deformity caused by fluoride Usually develops as limbs become weight bearing
Dental Fluorosis Brown Mottling of the teeth Occurs as adult teeth are forming in the gums (age 0-2)
Background Tindigani & Mtakuja 2004 Dental & Skeletal fluorosis Wells found to be high in fluoride No option of closing wells or piping water too expensive James Shorter PhD engineering student, 2006
Fluoride in the Environment The Hai District Fluoride in Groundwater Fluoride in Drinking Water Intervention Fig 2: Project Study Areas
Fluoride in the environment To Establish the source of fluoride Volcanic region Previous geological maps (desk study) Rock Samples
Fluoride in the groundwater To establish extent and severity of the problem Conducted survey of 150 water sources in Hai Analysed for fluoride, ph, Conductivity Collected GPS data on each source Created a map based on this data
Fluoride in the groundwater! Village Fluoride Levels (ppm) 0-0.2ppm 0.2ppm - 0.5ppm 0.5ppm - 1.0ppm 1.0ppm - 1.7ppm 1.7ppm - 3.1ppm 3.1ppm - 5.8ppm 5.8ppm - 10.6ppm 10.6ppm - 19.6ppm 19.6ppm - 34ppm
Results High Levels of fluoride concentrated in the South East South East has is a different geological system Boman gombe and Sanya Station have piped water Tindigani and Mtakuja villages most at risk became project focus
Two affected villages Fluoride in the drinking water In Hai Ranged from 0.1ppm 35ppm Mtakuja 5ppm 10ppm Tindigani 20ppm-35ppm
Survey of primary schools 1 Tindigani Mtakuja Total number of pupils surveyed 158 118 Total number of pupils resided in area since birth 148 88 Total number of pupils displaying signs of dental fluorosis 146 112 Total number of pupils displaying bone deformities 46 33 Table 1: Results taken from the surveys conducted in the primary schools of Tindigani and Mtakuja James P Shorter, John Massawe, Nadia Parry, Richard W Walker. Comparison of two village primary schools in northern Tanzania affected by fluorosis. International Health (2010); 2 (4): 269-274
Intervention Tindigani chosen as pilot site Prof. Eli Dahi based in Tanzania Bone char filter Constructed
Further Areas of Study
Skeletal fluorosis - April to Sept 09 Helen Jarvis
Results Research results Benefits for village
Research results 56 cases of clinical skeletal fluorosis identified Population of village 1435 Prevalence - 39/1000 (3.9%) Aged 2-30 X-ray changes Bloods, control data awaited
Result for village Pipe reconnected Each household educated on safe water use 13 severest cases referred for surgical correction
The future. Follow up Histology? Using results for practical purposes in other areas of Tanzania/world-wide
Engineering and Geochemistry Feasible low cost measure of fluoride for developing communities. High fluoride levels not a problem 13 years ago why? Change in Rainfall patterns? Change in water usage? Alternative intervention Solar stills Predictive geological model to identify potential problem areas Community education and water resource management
Medical What determines which individuals are affected by skeletal fluorosis? After intervention are there prospects for improvement in skeletal deformities? Foetal affects of high maternal fluoride intake.
Nutrition The affects of low calcium diet NB staple crop is maize (binds calcium in the gut). Can dietary interventions help to prevent/alleviate the problems? How much, if any, of the problem is due to intake of fluoride through diet? What is the affect on domestic animals/crops (no evidence)?
Dental Affects of in-utero exposure. Importance of timing and magnitude of exposure. Affects on other aspects e.g. dental caries