1)
Due to its ability to increase bone
mass, fluoride has been used as a treatment for osteoporosis.
However, despite 40 years of experimentation, fluoride remains
an experimental drug as of 2005, with current use mostly confined
to special research clinics.
2) A well documented side-effect from fluoride
therapy (doses = 20-34 mg/day) is
increased bone fracture. The increased fractures observed
among fluoride-treated patients have been found to occur most
frequently in the appendicular
skeleton region (arms, legs, and hip).
3) One of the most common sites for fluoride-induced
fracture has been the hip
- more specifically, the femoral neck. Several clinical trials
have reported a particularly high rate of spontaneous
fracture in the the femoral neck among fluoride-treated patients.
4) The high rate of spontaneous fracture among
fluoride-treated patients may relate to the increase in incomplete
fractures (i.e. "stress
fractures") well-documented among fluoride-treated patients.
5) Other well documented side effects of fluoride
treatment include: gastrointestinal
disorders, 'lower-extremity pain syndrome' (which may be a
result of stress fracture), and osteomalacia.
"Vertebral fracture rates and peripheral
bone density changes were surprising - and demonstrate that NaF
administration is capable of increasing vertebral fracture rates
and of increasing peripheral (nonspinal) bone loss. Thus our study
demonstrates the potential for an anti-osteoporosis agent, under
certain circumstances, to worsen a patient's clinical state."
SOURCE: Gutteridge DH, et al. (2002). A randomized trial of sodium
fluoride (60 mg) +/- estrogen in postmenopausal osteoporotic vertebral
fractures: increased vertebral fractures and peripheral bone loss
with sodium fluoride; concurrent estrogen prevents peripheral
loss, but not vertebral fractures. Osteoporosis International
13:158-70.
"We conducted an effectiveness meta-analysis to determine
the efficacy of fluoride therapy on bone loss, vertebral and nonvertebral
fractures and side effects in postmenopausal women...[A]lthough
fluoride has an ability to increase bone mineral density at the
lumbar spine, it does not result in a reduction in vertebral fractures.
Increasing the dose of fluoride increases the
risk of nonvertebral fractures and gastrointestinal
side effects without any effect on the vertebral fracture
rate."
SOURCE: Haguenauer D, et al. (2000). Fluoride for the treatment
of postmenopausal osteoporotic fractures: a meta-analysis. Osteoporosis
International 11:727-38.
"In this investigation, we found that after
5 years of fluoride treatment of osteoporotic patients, iliac
crest trabecular bone strength was reduced by 46-56% compared
with pretreatment biopsies. Also, 1 year
of fluoride administration seemed to reduce bone strength by 17-30%,
though this was not a significant finding... [T]he results
of this study support the investigations that have found an increased
rate of nonvertebral fractures, and a reduction in strength could
well be a direct effect of fluoride on trabecular bone."
SOURCE: Sogaard CH, et al. (1994). Marked decrease in trabecular
bone quality after five years of sodium fluoride therapy--assessed
by biomechanical testing of iliac crest bone biopsies in osteoporotic
patients. Bone 15: 393-99.
"Bone fragility during fluoride therapy for osteoporosis
was observed in 24 (37.5%) of 64 patients treated with sodium
fluoride, calcium, and vitamin D for 2.5 years who developed episodes
of lower-limb pain during treatment. Eighteen (28%) of these patients
had clinical and roentgenographic features of 41 stress
fractures and 12 new spinal fractures. There were 26
periarticular, six femoral neck, three
pubic rami, three tibia and fibula, one greater trochanter, and
two subtrochanteric fractures. Vertebral fractures appeared first,
then periarticular, then femoral neck, and lastly long-bone shaft
fractures. All fractures were spontaneous
in onset. The peripheral fracture rate
during treatment was three times that in untreated osteoporosis."
SOURCE: Schnitzler CM, et al. (1990). Bone fragility of the peripheral
skeleton during fluoride therapy for osteoporosis. Clinical
Orthopedics (261):268-75.
Fluoride treatment was "associated
with a significant three-fold increase
in the incidence of nonvertebral fractures, both incomplete and
complete...This increased rate of
fracturing suggests that bone formed
during fluoride therapy has increased fragility."
SOURCE: Riggs BL, et al. (1990). Effect of Fluoride treatment
on the Fracture Rates in Postmenopausal Women with Osteoporosis.
New England Journal of Medicine 322:802-809.
"Using all 61 fluoride-treated patients, femur fractures/patient
were significantly correlated to bone fluoride (p less than 0.05)
and to age (p less than 0.05)... These results
suggest that fluoride therapy may be implicated in the pathogenesis
of hip fractures which may occur in treated patients despite
a rapid, marked increase in bone mass."
SOURCE: Bayley TA, et al. (1990). Fluoride-induced fractures:
relation to osteogenic effect. Journal of Bone and Mineral
Research 5(Suppl 1):S217-22.
"We report clinical and bone morphometric findings in 18
osteoporotic patients who experienced stress fractures during
fluoride therapy... Fluoride appears to be a
key factor in the pathogenesis of stress
fractures, and may be associated with increased trabecular
resorption in some treated patients."
SOURCE: Orcel P, et al. (1990). Stress fractures of the lower
limbs in osteoporotic patients treated with fluoride. Journal
of Bone and Mineral Research 5(Suppl 1): S191-4.
"[T]he six hip fractures occurring in
patients receiving fluoride during 72.3 patient years of treatment
is 10 times higher than would be expected in normal women of the
same age. The probability of observing six fractures in
2 years is extremely small (0.0003). In four of the hip fracture
cases, the history suggested a spontaneous
fracture. These findings suggest that fluoride
treatment can increase the risk of hip fracture in osteoporotic
women."
SOURCE: Hedlund LR, Gallagher JC. (1989). Increased incidence
of hip fracture in osteoporotic women treated with sodium fluoride.
Journal of Bone and Mineral Research 2:223-5.
"Thirteen cases of spontaneous
fissure or fracture of the lower limbs observed in 8 patients
under treatment with sodium fluoride are reported... Fluor
seems to be responsible for the fissures
which cannot be avoided by calcium and/or vitamin D intake...
When such fissures occur, fluoride therapy must be discontinued
and the limb put at rest..."
Orcel P, et al. (1987). [Spontaneous fissures and fractures of
the legs in patients with osteoporosis treated with sodium fluoride].
Presse Med 16:571-5.
"How fluoride can produce stress
microfractures is unclear. That they are complications of
fluoride therapy is clear, as there
were no microfractures in the 101 patients in the calcium-treated
group."
SOURCE: O'Duffy JD, et al. (1986). Mechanism of acute lower extremity
pain syndrome in fluoride-treated osteoporotic patients. American
Journal of Medicine 80: 561-566.
"[T]he increased number of new crush fractures
of the spine during the first year of treatment raise the possibility
of fluoride-induced microfractures."
SOURCE: Dambacher MA, et al. (1986). Long-term fluoride therapy
of postmenopausal osteoporosis. Bone 7: 199-205.
"Two patients with moderate renal failure sustained spontaneous
bilateral hip fractures during treatment with fluoride, calcium,
and vitamin D for osteoporosis....As bilateral
femoral neck fractures are very rare these data suggest a causal
link between fractures and fluoride in patients with renal failure.
Thus fluoride should be given at a lower dosage, if at all, to
patients with even mild renal failure."
SOURCE: Gerster JC, et al. (1983). Bilateral fractures of femoral
neck in patients with moderate renal failure receiving fluoride
for spinal osteoporosis. British Medical Journal (Clin
Res Ed). 287(6394):723-5.
"During treatment bone pain increased
and three further vertebral compression
fractures occurred."
SOURCE: Compston JE, et al. (1980). Osteomalacia developing during
treatment of osteoporosis with sodium fluoride and vitamin D.
British Medical Journal 281: 910-911.
"Fractures and exacerbation of arthrosis were more frequent
in the fluoride group...The many fractures in
the fluoride group, 14 during treatment and the following month
as against 6 among the controls, were surprising. Three
or four of the fractures in the fluoride group appeared to be
spontaneous hip fractures.
In the past fractures have not been regarded as being caused by
fluoride but as resulting from prolonged osteoporosis before treatment.
We believe that the fluoride treatment here
was probably partly responsible for the fractures in our cases."
SOURCE: Inkovaara J, et al. (1975). Phophylactic fluoride treatment
and aged bones. British Medical Journal 3: 73-74.
