Table 2

The bidirectional MR analysis of leptin levels and T2D or glycemic traits

Exposure	Outcome	SNPs, n	Simple median		Weighted median		Inverse variance weighted		MR-Egger		MR-Egger
Exposure	Outcome	SNPs, n	β	P value	β	P value	β	P value	β	P value	Intercept	P value
T2D	Leptin (ng/mL)	121	0.015	0.108	0.003	0.785	0.004	0.662	−0.029	0.171	0.003	0.097
FG (mmol/L)		66	−0.002	0.955	−0.011	0.774	−0.021	0.477	−0.095	0.131	0.003	0.181
FI (pmol/L)		12	0.099	0.346	0.092	0.387	0.187	0.017	−0.040	0.873	0.007	0.349
HOMA-IR		14	0.271	0.008	0.267	0.012	0.329	0.001	−0.092	0.793	0.011	0.225
HOMA-β		27	0.087	0.247	0.035	0.633	0.112	0.060	−0.056	0.764	0.004	0.348
Leptin (ng/mL)	T2D	22	0.000	1.000	0.000	1.000	0.046	0.805	0.129	0.861	−0.003	0.907
	FG (mmol/L)	22	−0.024	0.617	−0.017	0.734	0.004	0.947	−0.196	0.418	0.006	0.393
	FI (pmol/L)	22	−0.022	0.655	−0.024	0.637	0.004	0.934	−0.062	0.767	0.002	0.745
	HOMA-IR	22	−0.034	0.518	−0.039	0.447	−0.005	0.933	−0.120	0.599	0.004	0.602
	HOMA-β	22	−0.026	0.498	−0.026	0.534	0.009	0.780	−0.051	0.709	0.002	0.650

The threshold of significance was at the Bonferroni-adjusted level p<0.005 (0.05/10).
Bold represents a significant P value.
FG, fasting glucose; FI, fasting insulin; HOMA-β, β-cell function; HOMA-IR, homeostasis model assessment-insulin resistance; MR, Mendelian randomization; SNPs, single nucleotide polymorphisms; T2D, type 2 diabetes.