Abstract
BACKGROUND: Inflammation is a crucial factor in the development of both osteoporosis and sleep disturbances; however, the mechanisms that connect these two conditions are not yet fully understood. This study aims to investigate the relationship among inflammation, osteoporosis, and sleep disturbances, and to assess whether osteoporosis acts as a mediating factor between inflammation and sleep disturbances. METHODS: This study conducted a cross-sectional analysis utilizing data from participants aged 50 and older, sourced from the NHANES database for the years 2005-2010 and 2017-2018. The primary objective was to investigate the associations among inflammatory markers, the Dietary Inflammatory Index (DII), osteoporosis, and sleep disturbances. All participants underwent measurement of inflammatory markers, including C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLR). Additionally, DII scores were computed to assess dietary inflammation. To account for potential confounding variables, such as age, sex, and body mass index (BMI), we conducted multivariable regression analyses. RESULTS: The results demonstrated that the 'osteoporosis with sleep disturbances' group exhibited significantly higher CRP levels and DII scores but lower NLR levels compared to the 'without osteoporosis and sleep disturbances' group. Among the four groups, two groups without sleep disturbances showed notably lower CRP levels. After controlling for potential confounding variables, we found a positive correlation among inflammatory markers, osteoporosis, and sleep disturbances. Notably, sex (with males as the reference group) moderated the relationship between inflammatory markers and sleep disturbances, demonstrating an adjusted effect size of - 0.430 for NLR (interaction p value = 0.008) and - 0.163 for CRP (interaction p value = 0.012). Additionally, a non-linear relationship was observed between NLR and sleep disturbances, as well as between NLR, DII, and osteoporosis. Mediation analysis indicated that osteoporosis partially mediates the effect of DII on sleep disturbances, accounting for 5.4574% of the total effect (p = 0.002). CONCLUSIONS: Men may exhibit a reduced resistance to inflammation-induced sleep disturbances in comparison to women. An increase in the DII may serve as a risk factor for both osteoporosis and sleep disturbances. Furthermore, osteoporosis partially mediates the relationship between the DII and sleep disturbances.