The impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease: a randomized controlled trial

Background: How bone properties would change after exercise intervention in patients with comorbidities are largely unknown. This study investigated the impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease (NAFLD). Methods: The study is a part of a large randomized controlled trial. Of the eligible participants, 63 postmenopausal women (aged 50-65 years) with prediabetes and NAFLD participated in either a progressive supervised Nordic walking training (60-75% VO2max intensity), 2-3 times/week, 30-60 min/sessions for 8.6-month (AEx, n=33), or maintained their daily lifestyle during intervention (Con, n=30). Bone mineral content (BMC) and density (BMD) of the whole body (WB), total femur (TF), femoral neck (FN) and lumbar spine (L2-4) were assessed by a dual-energy X-ray absorptiometry. Venous blood samples were analyzed for serum osteocalcin, pentosidine and receptor activator of nuclear factor kappa-B ligand (RANKL) levels by ELISA assay. Results: After 8.6-month intervention, the AEx group maintained their BMC TF , BMD TF , BMC L2-4 and BMD L2-4 , and increased their BMC FN (p<0.016), while the Con group decreased their BMC TF (p<0.008), BMD TF (p<0.001)) and BMD L2-4 (p<0.002). However, no significant group × time interaction was observed, except for BMD L2-4 (p=0.013). Decreased pentosidine was correlated with increased BMC WB (=-0.352, p=0.019).  The intervention has no significant effect on osteocalcin and RANKL.  Conclusions: Our results suggest that Nordic walking is effective in preventing bone loss among postmenopausal women with pre-diabetes and NAFLD. Changing of bone mass is associated with changing of pentosidine. However, this effect is not associated with osteocalcin and RANKL. Trial registration: ISRCTN registry, ISRCTN 42622771, registered 23 April 2013, https://www.isrctn.com/