Fluoride in drinking water in Madagascar and the development of a strategy for salt fluoridation.

OBJECTIVE: To update current knowledge of the distribution of drinking water fluoride content in Madagascar, in an effort to develop a strategy for the distribution of fluoridated salt to prevent tooth decay. BASIC RESEARCH DESIGN: In accordance with a strict protocol, water samples were collected from all the country's 22 regions. Fluoride concentration in ppm fluoride (F) was determined by use of a F ionselective electrode coupled with a pH/ion meter. RESULTS: A total of 651 sources of drinking water were sampled, of which 94% were found to have fluoride concentrations </= 0.7 ppm. The two regions with the highest number of water supplies with fluoride concentrations ⟩ 0.7 ppm are situated in the south and south-west of Madagascar. 87% of thermal springs have fluoride levels ⟩ 0.7 ppm, with a mean value of 2.21 +/- 1.64 ppm. CONCLUSIONS: These findings confirm that, with the exception of certain districts in the extreme south of Madagascar, fluoridated salt distribution would be appropriate for most regions in the country. This could be achieved by encouraging salt producers in the north and west of Madagascar, who are responsible for over 88% of national salt production, to fluoridate their salt. Most of this salt is distributed throughout the north and centre of the country, whereas very little is distributed to the extreme south.