It has been postulated that community water fluoridation may prevent skeletal bone loss and reduce the risk of osteoporotic fractures. However, data to support this hypothesis are not available. Three recent studies indicate that women living in communities with 4.0 ppm fluoride in the water system have lower levels of cortical bone and an increased risk of fracture when compared to women living in communities with 1.0 ppm fluoride. Another study indicates that both women and men living in areas with fluoridated water systems are at higher risk of hip fractures than those living in areas with negligible levels of fluoride in the drinking water. The purpose of the proposed study is to clarify the relationship between varying levels of water-borne fluoride and osteopenia as measured by decreased bone mineral density in adults aged 60 or older. Data will be collected on long-term residents of three similar communities in eastern Oregon and Washington. The communities have water fluoride levels of 0.06, 1.0, and 2.5 ppm. Approximately 105 women and 105 men in each of the three communities will be interviewed regarding known confounding variables and have their bone density evaluated via dual energy x-ray absorptiometry. The data will be analyzed to investigate whether bone mineral density differs between the three fluoride levels, when the density is adjusted statistically for values of the confounding variables. Evidence would be provided about whether people consuming fluoridated water have a different level of bone mineral density, which has important implications in regard to the existing public policy of community water fluoridation.
