Background. The aim of the work was to determine how the prolonged opioid addiction influence bone metabolism. In heroin addicts and after one year of methadone maintenance we investigated bone mineral density, biochemical markers of bone metabolism and serum levels of testosterone. Methods and Results. The study involved 37 persons, 31 men and 6 women in average age of 26 years (variation 18 to 39 years). Values of type I collagen cross-linked telopeptide, osteocalcin, propeptide of type I collagen and testosterone in serum were measured by radioimmunoassy and immunoanalysis. Bone mineral density was measured by dual energy absorptiometry. Body Mass Index was calculated. In heroin addicts at the femoral neck and in distal forearm osteopenia was found. After one year of methadone maintenance treatment the bone density remained unchanged. Concentrations of osteoresorption marker (type I collagen cross-linked telopeptide) and osteoformation markers (osteocalcin and propeptide of type I collagen) were in heroin addicts in comparison with control group significantly increased (averages 814 ng/l, 43,1 µ/l, 76,4 µ/l). Testosterone level in serum in addicted men was significantly decreased (3,3 nmol/l). After one year of methadone maintenance treatment biochemical markers of bonemetabolismrestored when compared with the control group, testosterone levels remained unchanged. Statistical measurements were performed by t-test and paired t-test. Conclusions. Prolonged heroin addiction is associated with accelerated bone turnover and osteopenia in cortical bone without evidence of metabolic bone disease. Methadone maintenance treatment restores altered bone turnover only. One possible explanation of high bone turnover in heroin addicts may be the influence of hypopituitary-hypothalamo- gonadal axis. However, it may not be the only mechanism involved.

        Key words: heroin addiction, osteoresorption, osteoformation, testosterone, methadone.