Parathyroidectomy leads to decreased blood lead levels in patients with refractory secondary hyperparathyroidism

Secondary hyperparathyroidism (SHPT) is characterized by high bone turnover and may result in increased release of lead (Pb) from bone stores. Parathyroidectomy (PTX) drastically changes bone remodeling. This study investigated the effects of PTX on the levels of blood lead (blood Pb) in patients with refractory SHPT.

The study included 30 patients on long-term hemodialysis (HD) who underwent PTX in the nephrology units of two Taiwanese hospitals. Changes in serum levels of intact parathyroid hormone (iPTH), bone-specific alkaline phosphatase (BAP), type 5b tartrate-resistant acid phosphatase (TRAP), total calcium (tCa), and blood Pb were analyzed.

After PTX, serum iPTH was markedly decreased while serum BAP was progressively increased and peaked 2weeks after PTX. Serum TRAP levels were progressively decreased during the 4week follow-up period. Serum tCa and blood Pb levels decreased sharply immediately after PTX. There was a positive correlation between the percentage of decrease in tCa and blood Pb at one day after PTX. Further analysis indicated a significant positive correlation between levels of blood Pb and serum iPTH (r=0.378, p<0.001), blood Pb and serum TRAP (r=0.180, p<0.05), and a negative correlation between blood Pb and serum BAP (r=-0.205, p<0.05).

PTX effectively suppressed the elevated levels of blood Pb and serum bone remodeling markers, which are common features of SHPT. In addition to decreased Pb release from bone, an increased store of Pb in bone may play a role in decreasing serum blood Pb levels. These findings suggest that patients undergoing PTX for refractory SHPT should strictly avoid environmental exposure to Pb.