[Effect of total parenteral nutrition on bone metabolism]

Total parenteral nutrition (TPN) for a prolonged period of time can be associated with bone pain and osteomalacia. We performed a study on the phosphorus/calcium metabolism and serum levels of osteocalcin (BGP), a protein proposed as constituting the bone turnover index in 31 patients receiving TPN (age 57 +/- 14 years, 22 males and 9 females) diagnosed as suffering from pathology of the digestive tract or geno-urinary pathology. The duration of the TPN was from 9.1 +/- 6.6 days (range 2-31 days). We observed and increase of FA (178 +/- 101 U/l), with a significant decrease of BGP (2.2 +/- 2.0 ng/ml vs. 3.7 +/- 1.3 ng/ml in controls; p less than 0.001). Serum levels of phosphorus and calcium corrected according to proteins were within normal limits. Hypercalciuria was detected in the urine (328 +/- 278 mg/24 hours), and phosphaturia (607 +/- 522 mg/24 hours). Based on the BGP results, we can conclude that patients subjected to TPN for a short period of time undergo a decrease in bone turnover.