Potential protective role of high Mediterranean diet adherence for systemic lupus erythematosus: mediation by liver and kidney function biomarkers in the UK Biobank cohort

Abstract Objectives Despite advances in the treatment of SLE, the complexity and high mortality of the disease drive the need to explore primary prevention strategies. The Mediterranean diet (MD) has shown benefits for various diseases, but its role in SLE remains controversial, lacking evidence from large prospective studies. This study aims to investigate the association between MD and SLE risk and to analyse the potential mediating role of MD-related biomarkers. Methods We selected 203 119 participants from the UK Biobank (UKB) who were free of SLE at baseline. Their adherence to the MD was assessed using the Mediterranean Diet Adherence Screener (MEDAS) score. Cox proportional hazards regression models were used to analyse the association between MD and SLE risk. Mediation analysis explored the potential mediating role of specific biomarkers. Results During a median follow-up of 10.6 years, 127 cases of SLE were observed. Moderate adherence to the MD did not show a significant association with SLE risk. However, high adherence was significantly associated with a reduced risk of SLE (hazard ratio: 0.61; 95% CI, 0.374–0.995). Mediation analysis revealed that this protective effect might be partially mediated by changes in liver and kidney function biomarkers, with mediation proportions ranging from 0.32% to 4.61%. Conclusion High adherence to the MD is significantly associated with a reduced risk of developing SLE. This beneficial effect may be partially mediated by improvements in liver and kidney function biomarkers, providing a scientific basis for further exploration of dietary interventions in the prevention of SLE.