Endocrine Abstracts

Background: In the multifarious etiopathogenesis of skeletal fragility, an intriguing novel element is the possible existence of a crosstalk between autonomic nervous system (ANS) function and bone health. Indeed, sympathetic overactivity might stimulate osteoclastogenesis and inhibit osteoblastic proliferation, whereas opposite effects would be exerted by a prevalent parasympathetic activation. Autonomic Nervous System Index (ANSI) is a percent ranked (0–100) unitary proxy of cardiac autonomic regulation (CAR), derived from the autoregressive spectral analysis of heart rate variability by combining the three most informative indexes. It is a simple and non-invasive method for evaluating ANS function, being by design free of age and gender bias. Notably, this index has also proved to highlight neurovegetative improvements induced by therapeutic strategies such as aerobic endurance exercise. In this respect, physical activity itself is well-known to play a key part in reducing (re)fracture risk.

Aim: To investigate CAR as well as the effects of a structured and personalized exercise program on CAR, skeletal turnover, bone mass and body composition, in postmenopausal women affected with osteopenia/osteoporosis.

Methods: 17 osteopenic/osteoporotic women aged between 50 and 70, referred to the Exercise Medicine Clinic of Istituto Auxologico IRCCS, were enrolled. Several evaluations, including bone turnover markers, CAR (by means of ANSI), body composition, and lifestyle (with ad hoc questionnaires) were performed, and a structured and personalized exercise program was prescribed.

Preliminary results and future perspectives: At the baseline assessment, bone turnover biomarkers were significantly impaired in comparison with reference populations from other studies. High variability in the ANSI score (32.5-79.5%) was observed. It will be interesting to explore CAR in a wider sample, as well as the effects of a customized exercise program both on bone metabolism and ANS function (as evaluated by non-invasive techniques), and their potential mutual correlation/interaction.