Endemic fluorosis -a model for studies examining the effect of fluoride on bone
The original publication is available at http://www.samj.org.za
The use of fluoride in the treatment of osteoporosis is complicated by concerns about the integrity of the newly formed bone, as well as the fact that not all patients respond to the drug. In an attempt to broaden insight into the varied skeletal response to fluoride exposure, we studied (clinical, dietary analysis, radiology, biochemistry and genetic markers) all 114 permanent inhabitants of an endemic fluorosis area. Unequivocal radiological evidence of osteofluorosis was present in 26% of subjects, while 48% had normal skeletal radiological results and 4% were found to be osteopenic. Twenty-two per cent were unclassifiable. Individuals with fluorosis were older and predominantly male. Although musculoskeletal symptoms occurred more frequently in patients with osteofluorosis, these subjects did not have an increased fracture prevalence and were, in fact, found to have a higher metacarpal as well as femoral cortical bone mass. In subjects with osteofluorosis, the average fluoride intake and residency in the area were similar to those of unaffected Kenhardt individuals, implying that there are causative factors other than fluoride exposure. Moreover, renal excretion of fluoride was comparable, as was the average energy, protein, mineral and alcohol intake. Mean serum calcium, phosphate, alkaline phosphatase, parathyroid hormone, calcitonin and 25-hydroxyvitamin D levels were unremarkable and similar in subjects with and without osteofluorosis. However, a family tree analysis of the population revealed that 4 very closely related subjects had osteopenia, which suggests that a genetic predisposition may at least partially explain why the skeletal response to fluoride is not determined by fluoride exposure alone.
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