Bone density and quality in prediabetes among postmenopausal Chinese women: the role of fibroblast growth factor 21

Abstract

Introduction: Prediabetes is associated with a worse trabecular bone score (TBS). Fibroblast growth factor 21 (FGF21) has been reported to be implicated in bone metabolism, and its levels are raised in prediabetes and other insulin-resistant states. We compared the bone mineral density (BMD) and TBS between prediabetes and normoglycaemia, and studied the correlation of FGF21 with BMD and TBS. Methods: Chinese postmenopausal women without type 2 diabetes were recruited from the Hong Kong Cardiovascular Risk Factor Prevalence Study between November 2016 and October 2018, and divided into prediabetes (fasting glucose ≥5.6 mmol/L or haemoglobin A1c ≥5.7%) and normoglycaemia. Both BMD and TBS were measured by dual-energy X-ray absorptiometry. Serum FGF21 levels were measured with an in-house enzyme-linked immunosorbent assay kit. Results: A total of 258 participants were included (130 prediabetes and 128 normoglycaemia). Bone mineral density was comparable between prediabetes and normoglycaemia, while TBS was lower in prediabetes (1.27±0.07 vs 1.30±0.07, P=0.007), which remained significant after adjustment for age and body mass index. Fibroblast growth factor 21 did not correlate with BMD but inversely correlated with TBS. On stepwise multiple linear regression models, FGF21 showed an independent inverse correlation with TBS (standardised beta -0.13, P=0.031), and remained significant with the inclusion in the model of homeostasis model assessment of insulin resistance. Conclusion: Among Chinese postmenopausal women, the bone quality was worse in prediabetes despite comparable bone density. Fibroblast growth factor 21 showed a significant independent correlation with TBS, suggesting its potential impact on the deterioration of the bone microarchitecture in prediabetes.