Table 3.

Mendelian randomization (MR) analysis of air pollution (particulate matter, nitrogen dioxide and nitrogen oxides, exposure) with primary liver cancer outcome in Asian population (East Asia).

Exposures	Methods	Beta	p	Number of SNPs	R2	F	P (Cochran’s Q heterogeneity test)	P (MR-Egger intercept test)	P (MR-PRESSO global test)
PM2.5	IVW	0.074	0.718	4	3.527%	87.086	0.057	0.714	0.133
	Weighted median	−0.050	0.769
	MR-Egger	0.300	0.660
	Simple mode	−0.086	0.706
	Weighted mode	−0.097	0.622
PM2.5–10	IVW	−0.131	0.362	3	3.371%	72.691	0.740	0.675	NA
	Weighted median	−0.116	0.490
	MR-Egger	0.070	0.885
	Simple mode	−0.040	0.865
	Weighted mode	−0.063	0.783
PM10	IVW	−0.026	0.720	5	4.933%	112.709	0.512	0.936	0.984
	Weighted median	−0.033	0.701
	MR-Egger	−0.037	0.814
	Simple mode	−0.037	0.783
	Weighted mode	−0.033	0.735
Nitrogen dioxide	IVW	−0.186	0.101	6	5.536%	126.644	0.308	0.337	0.368
	Weighted median	−0.194	0.171
	MR-Egger	0.569	0.463
	Simple mode	−0.204	0.385
	Weighted mode	−0.218	0.351
Nitrogen oxides	IVW	0.038	0.760	4	4.014%	95.452	0.613	0.412	0.652
	Weighted median	−0.014	0.921
	MR-Egger	−2.936	0.417
	Simple mode	−0.040	0.857
	Weighted mode	−0.038	0.853

PM, Particulate matter; MR: Mendelian randomization; IVW, Inverse variance weighted; SNPs, Single nucleotide polymorphisms.

R²: the percentage of iron status variability explained by each SNP; F statistic to assess the presence of a weak instrumental variable bias.