Relationship between bone formation markers bone alkaline phosphatase, osteocalcin and amino-terminal propeptide of type I collagen and bone mineral density in elderly men. Preliminary results.

Bone remodeling is altered in all metabolic bone diseases, especially in post-menopausal women and in the elderly. Predicting changes in bone mineral density (BMD) is useful to manage the progression of such diseases and to potentially provide interventions in reducing fracture risk. Continuous bone formation and resorption processes can be monitored by measuring biochemical markers of bone turnover (BTMs) and a relationship between BMD and BTMs has been known for long. The aim of this study was to evaluate the relationship between BMD and serum BTMs bone alkaline phosphatase (BAP), osteocalcin and amino-terminal propeptide of type I collegen (PINP) in elderly (>65 years) men. We prospectively studied 18 elderly men (median age=69, range=65-77 years) with no history of fractures, angina, stroke, myocardial infarction or diabetes mellitus. Patients who had undergone corticosteroid, calcitonin, androgen or bisphosphonate therapy were excluded from the study, as well as those who were vitamin D and calcium supplementation users. All the patients underwent lumbar-spine (L2-L4) dual-energy x-ray absorbtiometry and BMD, BAP, osteocalcin and PINP measurements. The mean BMD and body mass index (BMI) were 0.963±0.04 g/cm(2) and 24.4±1.2 kg/m(2), respectively. BAP, osteocalcin and PINP were 27.8±11.3 U/l, 25.6±7.1 ng/ml and 36.0±7.5 ng/ml, respectively. No correlation was found between BMD and BAP (R=-0.28, p=0.25), osteocalcin (R=-0.18, p=0.48) and PINP (R=-0.21, p=0.39), nor between BMI and both age (R=0.05, p=0.83) and BMD (R=0.10, p=0.67). In conclusion, we did not find any relationship between bone formation markers BAP, osteocalcin and PINP and bone density. Thus, our preliminary data suggest that BTMs are not useful in monitoring the bone mineral status of elderly men.