Bone and skeletal muscle changes in oldest-old women: the role of physical inactivity

Background Alterations in bone and muscle parameters related to advanced aging and physical inactivity have never been investigated in oldest-old women. Aims To investigate the impact of physical inactivity on bone mineral density (BMD) and body composition at the systemic and regional levels in oldest-old (> 75 years old) women. We hypothesized that, further to aging, alterations in bone and body composition parameters are exacerbated in the locomotor limbs that have experienced physical inactivity. Methods Whole-body and regional (lower limbs and trunk) BMD and fat-free soft tissue mass (FFSTM) were measured by means of dual-energy X-ray absorptiometry in 11 oldest-old wheelchair-bound women (OIW), 11 oldest-old mobile women (OMW), and 11 young healthy women (YW), all matched for weight (+/- 10 kg), height (+/- 10 cm). Results Whole-body BMD was reduced by 15% from YW to OMW and 10% from OMW to OIW. Whole-body FFSTM was also reduced from YW to OIW (- 13%). Lower limb BMD was progressively reduced among YW, OMW and OIW (- 23%). Similarly, lower limb FFSTM was reduced among YW (12,816 +/- 1797 g), OMW (11,999 +/- 1512 g) and OIW (10,037 +/- 1489 g). Trunk BMD was progressively reduced among YW, OMW and OIW (- 19%), while FFSTM was similar among the three groups 19801 g. Conclusions The results of the present study suggest that the alterations in bone and body composition parameters are exacerbated in the physical inactive oldest-old. These negative effects of physical inactivity are not confined to the locomotor limbs, and a systemic decline of bone and muscle parameters are likely associated with the physical inactivity.