Fluoride and sugar intake among adults and youth in Mauritius: preliminary results

Community water fluoridation, bone mineral density, and fractures: prospective study of effects in older women

OBJECTIVE

To determine whether fluoridation influences bone mineral density and fractures in older women.

DESIGN

Multicentre prospective study on risk factors for osteoporosis and fractures.

SETTING

Four community based centres in the United States.

PARTICIPANTS

9704 ambulatory women without bilateral hip replacements enrolled during 1986-8; 7129 provided information on exposure to fluoride.

MAIN OUTCOME MEASURES

Bone mineral density of the lumbar spine, proximal femur, radius, and calcaneus plus incident fractures (fractures that occurred during the study) of vertebrae, hip, wrist, and humerus.

RESULTS

Women were classified as exposed or not exposed or having unknown exposure to fluoride for each year from 1950 to 1994. Outcomes were compared in women with continuous exposure to fluoridated water for the past 20 years (n=3218) and women with no exposure during the past 20 years (n=2563). In women with continuous exposure mean bone mineral density was 2.6% higher at the femoral neck (0.017 g/cm(2), P<0.001), 2.5% higher at the lumbar spine (0.022 g/cm(2), P<0.001), and 1.9% lower at the distal radius (0.007 g/cm(2), P=0.002). In women with continuous exposure the multivariable adjusted risk of hip fracture was slightly reduced (risk ratio 0.69, 95% confidence interval 0.50 to 0.96, P=0.028) as was the risk of vertebral fracture (0.73, 0.55 to 0.97, P=0.033). There was a non-significant trend toward an increased risk of wrist fracture (1.32, 1.00 to 1.71, P=0.051) and no difference in risk of humerus fracture (0.85, 0.58 to 1.23, P=0.378).

CONCLUSIONS

Long term exposure to fluoridated drinking water does not increase the risk of fracture.

The association between water-borne fluoride and bone mineral density in older adults

While the benefit of fluoridation in the prevention of dental caries has been overwhelmingly substantiated, the effect of fluoride on bone mineral density is less clear. This cross-sectional study was designed to compare the bone mineral densities of older adults exposed to various levels of fluoride from community water systems. Participants were recruited from 3 rural communities with naturally occurring fluoride in their water systems at 0.03, 0.7, and 2.5 mg/L. All adults, age 60 and over, were eligible if they were ambulatory and had a long-term history (> or = 20 yrs) of ingesting city water. Bone mineral density (BMD) was measured by means of dual-energy x-ray absorptiometry at 3 anatomical sites: lumbar spine, proximal femur, and forearm. A total of 353 white non-Hispanic women and 317 white non-Hispanic men took part in the study. When the data were stratified by city of residence and gender, men and women living in the community with high levels of fluoride in their community water system had significantly higher lumbar spine BMD than their counterparts from the communities with low and moderate fluoride levels. The women in the high-fluoride community had significantly higher proximal femur BMD, but there were no statistically significant differences among men in either proximal femur or forearm BMD. Long-term exposure (> or = 20 yrs) to higher levels of fluoride appears to have a positive impact on lumbar spine and proximal femur BMD. Based on the results of this study, exposure to fluoride at levels considered "optimal" for the prevention of dental caries (from 0.7 to 1.2 mg/L) appears to have no significant impact on bone mineral density. The relationship between higher levels of fluoride exposure and bone mineral density requires further investigation.

Effects of iron salts in sucrose on dental caries and plaque in rats

Anaemia caused by iron deficiency and dental caries are still among the most prevalent diseases in some developing countries. Anaemia can be prevented by iron fortification of food. Previous studies demonstrated that iron-sucrose, which has been used for prevention of anaemia, reduces the incidence of caries in rats. The aim of the present study was to compare the influence of ferrous sulphate and ferric glycerophosphate co-crystallized with sucrose on the incidence of dental caries in rats. Forty-eight desalivated rats were caged in a programmed feeder and received their essential nutrition by gavage. The animals were fed 17 meals per day at hourly intervals of 88 parts/10(6) Fe++ or Fe co-crystallized with sucrose. Plain sucrose and calcium glycerophosphate with sucrose were used as control groups. Both ferric- and ferrous-sucrose meals reduced the incidence of smooth-surface and sulcal caries in rats. Stain formation, organic acid production and acidogenic activity of dental plaque in animals receiving iron-sucrose meals were also investigated. Ferric glycerophosphate did not induce extrinsic staining on the tooth surface. The concentration of organic acids did not differ significantly among the groups. The acidogenic activity of plaque in animals receiving either of the iron-sucrose meals tended to be lower than that of the control groups. The possibility that iron-sucrose might reduce the prevalence of two major public health problems, dental caries and anaemia, makes this preventive approach extremely attractive for additional investigation.