THE EFFECT OF FLUORIDATED DRINKING-WATER ON AXIAL BONE-MINERAL DENSITY - A POPULATION-BASED STUDY

Bone mineral density (BMD) of the spine and femoral neck was measured in a random stratified sample of 3222 perimenopausal women aged 47-59 years. A total of 969 women had used fluoridated drinking water (1.0-1 .2 mg/l) for over 10 years. These women were compared with 2253 women with low levels of fluoride in drinking water (< 0.3 mg/l). BMD of the spine was significantly higher in the fluoride group than in the non- fluoride group (1.138 +/- 0.165 vs. 1.123 +/- 0.156 g/cm(2), P = 0.026 ). Femoral neck BMDs did not differ between the groups. When the BMD v alues were adjusted for confounding factors (age, weight, menopausal s tatus, calcium intake, physical activity level, deliveries, alcohol co nsumption and estrogen use), the differences between the groups increa sed (P < 0.001 for the spine and P = 0.004 for the femoral neck, respe ctively). There was no significant difference between the groups in th e prevalence of self-reported fractures sustained during 1980-1989. We propose that the fluoridation of drinking water has a slight increasi ng effect on axial BMD in women in low fluoride areas.