Bidirectional Mendelian randomization analysis reveals the causal effects of nutrients on arthropathies

Arthropathy was related to macronutrients in an increasing number of studies nowadays. However, the causal effect of macronutrients and micronutrients on them remains unknown. The macronutrient and micronutrient summary statistics from the greatest genome-wide meta-analysis produced by the DietGen and other cohorts and genome-wide association studies statistics of arthropathy from FinnGen were used in this two-sample bidirectional Mendelian randomization investigation. The causal relationship between macronutrients and arthropathy was investigated using inverse variance weighting (IVW), Mendelian randomization (MR)-Egger regression, weighted median, weighted model, and simple mode. IVW estimates suggested that carbohydrates, Iron, Vitamin A, and gamma-tocopherol had casual associations with arthropathy. As for gonarthrosis, the IVW estimate of the carbohydrate (OR: 2.11, 95% CI: 1.20–3.73, P _IVW  = 9.70E−3); as for adhesive capsulitis of shoulder, the IVW estimate of Iron (OR: 1.29, 95% CI: 1.16–1.43, P _IVW = 2.80E−6); as for rheumatoid arthritis, the IVW estimate of Iron (OR: 1.17, 95% CI: 1.06–1.30, P _IVW = 3.00E−3); as for Coxarthrosis, the IVW estimate of Vitamin A (OR: 0.95, 95% CI: 0.94–0.97, P _IVW = 2.70E−8); as for adhesive capsulitis of shoulder, the IVW estimate of gamma-tocopherol (OR: 0.36, 95% CI: 0.29–0.44, P _IVW = 3.50E−21); in the reserve MR analysis, as for carbohydrate, the IVW estimate of juvenile arthritis (OR: 0.99, 95% CI: 0.99–1.00, P _IVW = 4.50E−3); as for protein, the IVW estimate of juvenile arthtitis (OR: 1.01, 95% CI: 1.00–1.01, P _IVW = 2.40E−3). As risk factors, this MR investigation discovered that in macronutrients, carbohydrates were causally linked to gonarthrosis and juvenile arthritis. Protein was related to juvenile arthritis. Iron was obviously associated with adhesive capsulitis of the shoulder and rheumatoid arthritis. Vitamin A was related to Coxarthrosis. Gamma-tocopherol related to adhesive capsulitis of the shoulder and gout. To fully understand how they affect arthropathy, more research is required.