BGLAP and hyperparathyroidism: A similar phenomenon was observed in the studies conducted by Stellbrink et al.,5 Samarawickrama et al.8 and Masiá et al.21 They reported an increase in PTH, ALP, BALP, P1NP and osteocalcin values in participants exposed to TDF treatment which was evidence of increased bone turnover.5 TDF-use was, however, not found to be associated with 25-dihydroxyvitamin D deficiency, hyperparathyroidism, increased BTM or reduced BMD.8