Fewer bone histomorphometric abnormalities with intermittent than with continuous slow-release sodium fluoride therapy

Addition of monofluorophosphate to estrogen therapy in postmenopausal osteoporosis: a randomized controlled trial

INTRODUCTION

Treatment of osteoporosis with high-dose fluoride alone does not reduce fracture risk. We hypothesized that the antifracture efficacy of fluoride could be optimized by its use in low doses combined with an antiresorptive agent.

EXPERIMENTAL SUBJECTS

Subjects included 80 women with postmenopausal osteoporosis who had been taking estrogen for at least 1 yr.

METHODS

Subjects were randomized to receive monofluorophosphate (MFP) (fluoride content of 20 mg/d) or placebo over 4 yr in a double-blind trial.

RESULTS AND DISCUSSION

There were progressive increases in lumbar spine bone density over the duration of the study (MFP, 22%; placebo, 6%; P < 0.0001). In the trabecular bone of L3, these increases were even greater (MFP, 49%; placebo, 2.5%; P < 0.0001). In the proximal femur, there were smaller but significant treatment effects (P = 0.015). Total body scans and their subregions also showed significantly greater increases in the MFP group. Bone formation markers increased significantly in the MFP group at yr 1. Hyperosteoidosis was present in biopsies from five of seven MFP subjects, with osteomalacia in two of seven. The hazards ratio for vertebral fractures was 0.20 (95% confidence interval, 0.05-1.30), and the incidence rate ratio was 0.12 (95% confidence interval, 0.06-0.23; P < 0.01). The hazards ratio for nonvertebral fractures was 3.3 (95% confidence interval, 0.8-12.0).

CONCLUSIONS

We conclude that fluoride at 20 mg/d produces substantial increases in bone mineral density but still interferes with bone mineralization. This indicates that most previous studies with this ion have used toxic doses and that much lower doses should be assessed to find a safe dose window for the use of this powerful anabolic agent.

Position of the American Dietetic Association: the impact of fluoride on health

Fluoride is an important element for mineralization of body tissues. The use of topical and systemic fluoride for oral health has resulted in major reductions in dental caries and its associated disability. Fluoridation of public water supplies has been endorsed by over 90 professional health organizations as the most effective dental public health measure in existence. Still, about half of the US population fails to receive the maximum benefits possible from community water fluoridation and the use of fluoride products. Fluoride also plays a role in bone health. The role of high doses of fluoride for prevention of osteoporosis is undergoing active study and is considered experimental at this point. Dietetics professionals should routinely monitor and promote the use of systemic and topical fluorides, especially in children and adolescents. The American Dietetic Association strongly reaffirms its endorsement of the use of systemic and topical fluorides, including water fluoridation, at appropriate levels of intake, as an important public health measure. However, clients should be cautioned that experimental use of high intakes of fluoride should be avoided unless they are participating in clinical trials.

Position of the American Dietetic Association: the impact of fluoride on health

Fluoride is an important element for mineralization of body tissues. The use of topical and systemic fluoride for oral health has resulted in major reductions in dental caries and its associated disability. Fluoridation of public water supplies has been endorsed by over 90 professional health organizations as the most effective dental public health measure in existence. Still, about half of the US population fails to receive the maximum benefits possible from community water fluoridation and the use of fluoride products. Fluoride also plays a role in bone health. The role of high doses of fluoride for prevention of osteoporosis is undergoing active study and is considered experimental at this point. Dietetics professionals should routinely monitor and promote the use of systemic and topical fluorides, especially in children and adolescents. The American Dietetic Association strongly reaffirms its endorsement of the use of systemic and topical fluorides, including water fluoridation, at appropriate levels of intake, as an important public health measure. However, clients should be cautioned that experimental use of high intakes of fluoride should be avoided unless they are participating in clinical trials.

Intermittent and continuous administration of the bisphosphonate ibandronate in ovariohysterectomized beagle dogs: effects on bone morphometry and mineral properties

Bisphosphonates have emerged as a valuable treatment for postmenopausal osteoporosis. Bisphosphonate treatment is usually accompanied by a 3-6% gain in bone mineral density (BMD) during the first year of treatment and by a decrease in bone turnover. Despite low bone turnover, BMD continues to increase slowly beyond the first year of treatment. There is evidence that bisphosphonates not only increase bone volume but also enhance secondary mineralization. The present study was conducted to address this issue and to compare the effects of continuous and intermittent bisphosphonate therapy on static and dynamic parameters of bone structure, formation, and resorption and on mineral properties of bone. Sixty dogs were ovariohysterectomized (OHX) and 10 animals were sham-operated (Sham). Four months after surgery, OHX dogs were divided in six groups (n = 10 each). They received for 1 year ibandronate daily (5 out of 7 days) at a dose of 0, 0.8, 1.2, 4.1, and 14 microg/kg/day or intermittently (65 microg/kg/day, 2 weeks on, 11 weeks off). Sham dogs received vehicle daily. At month 4, there was a significant decrease in bone volume in OHX animals (p < 0.05). Doses of ibandronate >/= 4.1 microg/kg/day stopped or completely reversed bone loss. Bone turnover (activation frequency) was significantly depressed in OHX dogs given ibandronate at the dose of 14 microg/kg/day. This was accompanied by significantly higher crystal size, a higher mineral-to-matrix ratio, and a more uniformly mineralized bone matrix than in control dogs. This finding lends support to the hypothesis that an increase in secondary mineralization plays a role in gain in BMD associated with bisphosphonate treatment. Moreover, intermittent and continuous therapies had a similar effect on bone volume. However, intermittent therapy was more sparing on bone turnover and bone mineral properties. Intermittent therapy could therefore represent an attractive alternative approach to continuous therapy.