Water fluoridation, dentition status and bone health of older people in Ireland.

OBJECTIVE To examine some of the potential benefits and risks of water fluoridation for older adults. METHODS This study used 'The Irish Longitudinal Study on Ageing', to access a nationally representative sample of 4977 people aged 50 and older. The sample was used to estimate associations between the percentage of households in a respondent's local area with a currently fluoridated water supply and the probability of two binary outcomes: the respondent having all their own teeth and having normal bone density. Past exposure of individuals to fluoridated water was not assessed; the prevalence of fluoridated water in local supplies was obtained from the 2006 Census of Ireland. The Census data indicated that there was considerable variation in the proportion of households with fluoridated water supplies, especially in rural areas. Bone mineral density was estimated from a heel ultrasound of each respondent, and their number of teeth was self-reported. A range of individual variables, such as educational attainment, housing wealth, age and health behaviours, was controlled for. RESULTS It was found that the greater the percentage of households with a fluoridated water supply in an area, the higher the probability that respondents had all their own teeth. There was no significant relationship between the proportion of households with a fluoridated water supply in an area and bone health. CONCLUSION This study suggests that water fluoridation provides a net health gain for older Irish adults, though the effects of fluoridation warrant further investigation.