Alendronate and Parathyroid Hormone

To the Editor: Black et al. 1 and Cosman et al. 2 (Aug. 11 issue) report that combinations of parathyroid hormone and alendronate are beneficial in the treatment of osteoporosis. However, it appears possible that coexisting subclinical osteomalacia may have clouded both the diagnosis and the interpretation of the results. In a study of elderly subjects in Ireland with vitamin D deficiency, my colleagues and I observed a surprisingly larger number who had low serum levels of 25-hydroxyvitamin D as well as mildly abnormal calcium, phosphorus, and alkaline phosphatase levels. 3 , 4 Cosman and colleagues found a similar pattern of low serum levels . . .