Iron, copper, zinc and magnesium on rheumatoid arthritis: a two-sample Mendelian randomization study

Figures & data

Figure 1. MR analysis results of exposures (iron, copper, zinc, and magnesium) and outcome (rheumatoid arthritis). Five methods: random-effects IVW, MR Egger, weighted median, simple mode, and weighted mode.

Figure 2. Scatter plot. a: iron and rheumatoid arthritis; b: copper and rheumatoid arthritis; c: zinc and rheumatoid arthritis; d: magnesium and rheumatoid arthritis.

Figure 3. Leave one out analysis. a: iron and rheumatoid arthritis; b: copper and rheumatoid arthritis; c: zinc and rheumatoid arthritis; d: magnesium and rheumatoid arthritis.

Figure 4. The normal distribution plot of MR analysis. a: iron and rheumatoid arthritis; b: copper and rheumatoid arthritis; c: zinc and rheumatoid arthritis; d: magnesium and rheumatoid arthritis.

Figure 5. MR analysis results of exposures (iron, copper, zinc, and magnesium) and outcome (rheumatoid arthritis). Three methods: maximum likelihood, penalised weighted median, and IVW (fixed effects).

Table 1. Sensitivity analysis of the MR analysis results of exposure and outcome.

Exposure	Outcome	Heterogeneity Test		Pleiotropy Test	MR-PRESSO		MR-RAPS
		Cochran’s Q Test (P value)	Rucker’s Q Test (P value)	Egger Intercept (P value)	Distortion Test	Global Test	Normal Distribution
		IVW	MR-Egger	MR-Egger	Outliers	P value	P value
Iron	Rheumatoid arthritis	0.025	0.052	0.210	NA	0.061	0.996
Copper		0.947	0.883	0.927	NA	0.955	—
Zinc		0.630	0.590	0.465	NA	0.580	0.135
Magnesium		0.101	0.075	0.954	NA	0.142	0.355

Data availability statement

This study analyzed publicly available datasets that can be accessed via the FinnGen consortium (https://www.finngen.fi/) and the IEU OpenGWAS database (https://gwas.mrcieu.ac.uk/).