The systemic inflammation response index is independently associated with incident fracture risk in older women

This study investigated the link between the systemic inflammation response index (SIRI) and fracture risk in elderly women. Higher SIRI was associated with increased fracture risk, independent of clinical risk factors and bone mineral density, suggesting SIRI may be valuable for enhancing fracture risk assessment models. PURPOSE: The systemic inflammation response index (SIRI), including monocytes, neutrophils, and lymphocytes (SIRI = monocytes x neutrophils/lymphocytes), has been linked to various health outcomes, including osteoporosis. This study aimed to explore the association between SIRI and fracture risk in elderly women. METHODS: In a Swedish prospective cohort of 2965 women aged 75-80 years, baseline examinations included blood analyses, dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), physical function tests, and questionnaires. Cox proportional hazards regression models were used to assess associations between SIRI and incident fracture risk. RESULTS: The median follow-up time was 8 years (IQR 7.2-8.8), during which 230 hip fractures, 790 major osteoporotic fractures (MOF), and 1059 any type of fracture occurred. Higher SIRI was significantly linked to an increased risk of hip fracture (hazard ratio [HR] per 1 SD increase 1.18, 95% CI [1.07-1.32], p < 0.01), MOF (1.10 [1.03-1.18], p < 0.01), and any fracture (1.11 [1.05-1.17], p < 0.001) independent of age, BMI, clinical risk factors (CRFs), and femoral neck bone mineral density (FN BMD). SIRI was related to poorer physical function (timed up-and-go [TUG], 11.8%, p < 0.05, highest [Q5] compared to the lowest [Q1] quintile of SIRI) and lower activity levels (physical activity scale for the elderly [PASE], -28.8%, p < 0.05, Q5 vs. Q1). SIRI was positively associated with cortical porosity and trabecular number, but not with BMD measured by DXA. CONCLUSION: SIRI was positively and independently associated with incident fracture risk. Further studies are needed to establish whether SIRI provides additional value beyond existing risk factors.