47Ca turnover in endemic fluorosis and endemic genu valgum

1. Calcium turnover was determined after intravenous injection of radioactive 47Ca in patients with fluorosis and endemic genu valgum and in age-matched controls. Total Ca turnover in the body, loss of Ca from the body in urine, faeces and sweat (external turnover) and bone mineralization rate were calculated from whole-body retention of 47Ca and specific activity of 47Ca in serum. 2. Total Ca turnover was significantly higher in younger subjects than in older subjects. 3. Total Ca turnover was significantly higher in patients with fluorosis and in those with endemic genu valgum than in age-matched controls, but the external turnover of Ca was lower in both groups of patients than in controls. 4. Bone mineralization rate was significantly higher in patients with fluorosis and in those with genu valgum as compared to age-matched controls. 5. Total body Ca turnover and bone mineralization rates were significantly higher in patients with endemic genu valgum than in those with fluorosis. The differences persited even after adjusting for differences in age between patients with fluorosis and those with genu valgum.