Dietary magnesium intake and rheumatoid arthritis patients' all-cause mortality: evidence from the NHANES database

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease with all-cause mortality increasing globally. Dietary magnesium (Mg), an anti-inflammatory nutrient, has been proven to be associated with the all-cause mortality. The association of dietary Mg intake and all-cause mortality in RA patients remains unknown. The aim of this study was to assess the association between dietary Mg intake and all-cause mortality in RA patients.

RA patients were extracted from the NHANES 1999-2018, and followed for survival through December 31, 2019. Dietary Mg intake data were obtained from 24-h dietary recall interview. The association between dietary Mg intake and RA patients' all-cause mortality was explored based on weighted univariate and multivariate Cox proportional hazard models and described as absolute risk difference (ARD), hazard ratios (HRs) and 95% confidence intervals (CIs). This association was further explored in subgroup analyses based on different age, gender and body mass index (BMI).

Totally 2,952 patients were included. Until 31 December 2019, a total of 825 deaths were documented. RA patients with higher dietary Mg intake had a 11.12% reduction of all-cause mortality (ARD=-11.12%; HR = 0.74, 95%CI: 0.56-0.99) in the fully adjusted model, especially in female (HR = 0.68, 95%CI: 0.47-0.98), aged < 65 years (HR = 0.59, 95%CI: 0.37-0.94) and BMI ≤ 30 kg/m² (HR = 0.62, 95%CI: 0.42-0.91).

RA patients who consumed adequate dietary Mg from diet as well as supplements may had a lower risk of all-cause mortality.