Table 2.

Positive control two-sample Mendelian randomisation analysis of the relationship between strenuous sport and other exercise (SSOE), and body fat percentage. This analysis was used to chose the best instrument for analysis of the relationship between SSOE and ALS. The liberal instrument appears to produce more precise estimates with smaller standard errors and greater power, due to the larger number of SNPs. Although MR RAPS is significant in both the liberal and conservative analysis, the conservative tool paradoxically identifies a positive relationship between SSOE and body fat percentage.

Positive control instrument	Multiplicative random effects IVW beta	Fixed effects IVW p-value	Multiplicative random effects IVW p-value	Weighted median p-value	MR-Egger p-value	Weighted mode p-value	MR RAPS p-value
Conservative (p<5E-08)	-0.78	0.003	0.01	0.23	0.97	0.37 (falsely positive beta)	0.04 (falsely positive beta)
Liberal (p<1E-06)	-0.64	0.000004	0.00002	0.03	0.85	0.64	0.0004 (correctly identified negative beta)