Association of metabolic score for visceral fat with fragility fracture risk: The combined and mediating roles of arterial stiffness.

Abstract

To investigate the combined effect of the metabolic score for visceral fat (METS-VF) and arterial stiffness on fragility fractures, and to further examine whether arterial stiffness, measured by brachial-ankle pulse wave velocity (baPWV), mediates the association between METS-VF and fragility fractures. The study included 42,256 participants (mean age, 49.42 ± 13.05 years, 73.36 % male) from the Kailuan cohort, with complete baPWV and METS-VF data, followed until 2022. METS-VF ≥ 6.86 was defined as the high group and < 6.86 as the low group, while baPWV ≥1800 cm/s was defined as the arterial stiffness group and < 1800 cm/s as the normal group. Participants were further classified into four combined groups, with the low METS-VF and normal baPWV group serving as the reference group. Multiplicative and additive interaction analyses were applied, and Cox regression models estimated hazard ratios (HRs) with 95 % confidence intervals (CIs). Mediation analysis assessed the role of baPWV. During a mean follow-up of 7.47 years, 367 participants experienced fragility fractures. A significant additive interaction between METS-VF and baPWV was observed. (Additive: relative excess risk due to the interaction [RERI] = 0.51, 95 % CI 0.04-0.98; Multiplicative, HR = 0.73, 95 % CI 0.69-1.71). After adjusting for covariates, HRs for incident fractures compared to the reference group were 1.39 (95 % CI, 1.02-1.90) for Group 2, 2.21 (95 % CI, 1.60-3.04) for Group 3, and 3.32 (95 % CI, 2.40-4.57) for Group 4. Additionally, baPWV mediated 13.08 % of the association between METS-VF and fracture risk. Higher METS-VF and arterial stiffness levels were associated with an increased risk of fragility fractures, and arterial stiffness, assessed by baPWV, partly mediated this association.