Is Vitamin D Deficiency the Cause or the Effect of Systemic Lupus Erythematosus: Evidence from Bidirectional Mendelian Randomization Analysis

Table 1

Details on GWAS predictive strength of IVs used in Mendelian randomization analyses.

Study design		Details of GWAS (exposures)		Strength of IVs
Exposure	Outcome	Consortium	Sample size	Model	No. of SNPs		-statistic
Vitamin D	Systemic lupus erythematosus	UK biobank	304,818	Model 1	53	0.585	33.863
				Model 2	46	0.537	30.883
25-Hydroxyvitamin D	Systemic lupus erythematosus	UK biobank	401,460	Model 1	160	0.459	12.452
				Model 2	147	0.431	11.827
Systemic lupus erythematosus	Vitamin D	FinnGen biobank	213,683	Model 1	8	0.088	23.433
				Model 2	7	0.071	21.837
Systemic lupus erythematosus	25-Hydroxyvitamin D	FinnGen biobank	213,683	Model 1	38	0.551	31.152
				Model 2	33	0.463	26.169

Model 1: SNPs associated with any potential confounders were not extracted. Model 2: SNPs associated with any potential confounders were extracted. SNP: single-nucleotide polymorphisms.