Determinants of age-associated changes in os calcis ultrasonic indices in elderly women: potential involvement of geriatric hyposomatotropism in bone fragility.

OBJECTIVE

ultrasound measures a clinically relevant property of bone strength in addition to and distinct from bone mass. The aim of the present study was to examine the effects of healthy ageing on ultrasound measurements of the calcaneus.

DESIGN

cross-sectional study.

STUDY

PARTICIPANTS

a sample of 177 community-dwelling healthy women aged 70-87 years. Exclusion criteria were diseases or medications known to affect the musculoskeletal system or the somatotrophic axis.

MEASUREMENTS: serum levels of 1,25-dihydroxyvitamin D3 and insulin-like growth factor-I (IGF-I) were measured by radioimmunoassay, serum 25-hydroxyvitamin D3 (25(OH)D3) was determined by competitive binding assay and serum parathyroid hormone was assessed immunochemically. Isometric and isokinetic quadriceps strength were evaluated using a Cybex II system. Calcaneal ultrasound indices--broadband ultrasound attenuation (BUA) and speed of sound (SOS)--were measured with an Achilles system.

RESULTS

we found a significant decrease with ageing in BUA and SOS (-0.5 and -1.3% per year, respectively), suggesting a continuing loss of bone quality. Quadriceps strength, serum IGF-I and 25(OH)D3 constituted the best predictors of BUA, while IGF-I was the only parameter found to be independently associated with SOS.

CONCLUSION

these findings suggest that, among other factors, the activity of the growth hormone-IGF-I axis is of importance for skeletal integrity. Age-related bone fragility may, in part, be related to geriatric hyposomatotropism.