Table 1. BMI-associated known metabolites classified into cause, effect, or bidirectional group based on their IV effect estimate p-values.

Y ~ X, regression of Y on X; B, BMI; M, metabolite; covariate adjustment for B and M described in Methods; β, effect size estimate; SNP, hg19 chromosome:position is shown; EA, effect allele (i.e. metabolite level-increasing allele). IV effect estimate p-values < 0.05 are in bold italic.

Group	Metabolite	Observational Association		Metabolite Instrument			GM IV Estimate (M → B)		GB IV Estimate (B → M)
		β B ~ M	P B ~ M	SNP	EA	P M ~ GM	β	P	β	P
Cause	alpha-hydroxybutyrate	0.235	7.09E-13	11:119745598	T	4.82E-07	−0.040	1.24E-03	−0.036	8.36E-01
	C34:4 PC	0.153	3.45E-06	3:182171263	A	1.42E-07	−0.027	9.90E-03	0.019	9.15E-01
	C6 carnitine	0.207	2.66E-10	1:76224010	C	2.88E-24	−0.010	3.09E-02	−0.076	6.69E-01
	C18:1 CE	−0.215	5.54E-11	20:38984849	T	3.44E-07	−0.016	4.23E-02	−0.018	9.17E-01
	cotinine	−0.169	3.10E-07	10:123918365	C	1.07E-06	0.012	8.03E-02	−0.022	9.02E-01
Effect	valine	0.445	1.20E-47	14:32724292	A	7.01E-08	−0.003	6.94E-01	0.708	1.46E-03
	C22:6 LPC	−0.180	4.38E-08	18:71068347	A	3.26E-07	−0.001	9.52E-01	−0.450	2.25E-02
	C18 carnitine	−0.193	4.65E-09	6:110760008	A	1.27E-07	0.001	9.41E-01	−0.351	6.53E-02
Bidirectional	glycine	−0.308	7.55E-22	2:211540507	A	2.35E-30	0.030	6.03E-10	−0.712	1.59E-03
	tyrosine	0.376	6.22E-33	6:111477887	C	1.12E-07	−0.022	8.77E-03	0.334	7.46E-02