Table 4. Associated factors of serum and tears VEGF.

Variables	Regression coefficient (b)	t-stats	p-value	Regression coefficient (b)	t-stats	p-value
	Simple Linear Regression*			Multiple Linear Regression**
Serum VEGF
Age	-3.10	-1.68	0.097	-0.09	-0.80	0.428
Gender	-9.89	-0.26	0.797
Race	186.31	2.11	0.380
Smoking status	-11.64	-0.63	0.533	-0.07	-0.66	0.514
Duration of DM	7.65	1.29	0.202	0.08	0.70	0.487
Hypertension	-38.08	-0.87	0.386
Dyslipidaemia	31.58	0.75	0.454
Severity of DR	54.16	2.43	0.017	0.14	0.91	0.364
Tears VEGF	0.71	2.49	0.015	0.71	2.49	0.015
Tear VEGF
Age	-2.46	-3.94	<0.001	-0.55	-0.72	0.476
Gender	8.71	0.64	0.526
Race	-18.31	-0.56	0.579
Smoking status	0.47	0.07	0.944	1.63	0.34	0.737
Duration of DM	5.11	2.45	0.016	1.51	0.69	0.498
Hypertension	-13.14	-0.84	0.407
Dyslipidaemia	-10.33	-0.69	0.493
Severity of DR	55.23	9.54	<0.001	49.67	5.48	< 0.001
Serum VEGF	0.10	2.49	0.015	0.03	0.93	0.358

*Simple Linear Regression test, p < 0.25, significant

**Multiple Linear Regression test, p < 0.05, significant

Forward, Backward, Stepwise and Enter method were applied

Abbreviation: DM: diabetes mellitus, DR: diabetic retinopathy, VEGF: vascular endothelial growth factor