Quantitative tetracycline-based analysis of iliac bone biopsy was performed in 17 patients with endemic skeletal fluorosis. All had lived in endemic fluorosis areas since their birth. The mean age was 25.6 years and duration of symptoms 7.6 years. The mean fluoride content of the drinking water was 17.8 ppm and the mean daily intake of fluoride was 26.2 mg. None of the patients had Vitamin D deficiency, intestinal malabsorption or renal dysfunction.
Pertinent biochemical findings were: raised plasma levels of fluoride, alkaline phosphatase and iPTH, and increased urinary fluoride excretion. Static and dynamic histomorphometric measurements revealed the profiles of osteomalacia and secondary hyperparathyroidism in varying combinations in all cases. Increases in osteoid volume, osteoid surfaces, osteoid seams width, resorption surfaces and mineralization lag time and decreases in corrected apposition rate, bone formation rates and tetracycline labeled surfaces were the variable features recorded in each case.
Dynamic bone histomorphometry has further increased the understanding of the effects of fluoride on intraskeletal mechanisms affecting the structure and metabolism of the bone but it does not allow clear-cut differentiation from metabolic bone disease. Endemic skeletal fluorosis, therefore, may be regarded as a parametabolic bone disease.