Association between dietary inflammatory index and asthmatic patients with sleep disorders in American adults, NHANES 2005-2020

Background Chronic airway inflammation, recognized as the core pathological mechanism of asthma, may disrupt circadian rhythms through neuroimmune modulation mediated by inflammatory mediators. Emerging evidence suggests a markedly elevated prevalence of sleep disturbances among asthma patients, while dietary patterns modulating systemic inflammatory balance present feasible intervention targets. However, the association between Dietary Inflammatory Index (DII) and comorbid sleep disorders in asthma remains underexplored. Method This cross-sectional study analyzed data from 4,443 asthmatic adults with sleep disorders in NHANES (2005-2020). DII scores were calculated using 28 food parameters from two 24-h dietary recalls. Weighted multivariable logistic regression models were employed to examine DII-sleep disturbance associations with sequential adjustment for demographic, lifestyle, and clinical confounders. Restricted cubic spline (RCS) analysis evaluated nonlinear relationships and inflection points. Gender heterogeneity and subgroup interactions were assessed through stratified analyses. Result Multivariable analysis demonstrated significant dose-response relationships between elevated DII and sleep disturbance risk (P for trend <0.001). Participants in the highest DII quartile (Q4) demonstrated 47% increased risk compared to Q1 (OR:1.47, 95%CI:1.19-1.83). Full adjustment attenuated this association (Model 2 OR = 1.27, 0.99-1.62; p = 0.06), though borderline significance persisted (P for trend = 0.05). RCS analysis revealed a U-shaped nonlinear association (inflection point: DII = 1; p < 0.05) with significant gender heterogeneity. Males exhibited pronounced U-shaped trends (p < 0.05), contrasting with linear patterns in females (p > 0.05). Poverty-income ratio demonstrated significant interaction (p < 0.05), while other subgroups showed no significant interaction (p > 0.05). Conclusion The U-shaped DII-sleep disturbance underscores the critical importance of implementing anti-inflammatory dietary strategies in comprehensive asthma management.