BACKGROUND: Opioids influence bone metabolism in several ways and osteoporosis associated with the long-term use of opioids is believed to be multifactorial.OBJECTIVES: To investigate the effect of opioid dependence on conventional and novel biochemical parameters of bone metabolism. To evaluate whether the concomitant HCV infection affects these parameters.METHODS: Fifty-nine opioid-dependent subjects and 23 healthy volunteers participated in the study. Parameters of bone metabolism were determined in serum. The determined parameters were procollagen type I N-terminal propeptide (PINP), serum Beta-Crosslaps Ι (β-CTX), total calcium (Ca), inorganic phosphorus (P), parathormone (PTH) and alkaline phosphatase bone isoenzyme (ALP).RESULTS: The results of our study show that opioid-dependent subjects exhibit higher values in those biochemical markers that are indicative of increased osteoclast activity, such as β-CTX and ALP, compared to healthy subjects. Furthermore, in opioid-dependent subjects the values of PTH were lower, while those of PINP were higher, in comparison to healthy individuals. No significant difference in the studied parameters was found when opioid-dependent subjects positive for anti-HCV antibodies were compared with opioid-dependent subjects negative for anti-HCV antibodies.CONCLUSION: Our findings show that there is increased bone turnover (bone metabolism) in opioid-dependent subjects, compared to healthy individuals. Future research on bone mineral density in these patients will help us evaluate whether the bone remodeling process is balanced or not.