Table 5. Linear regression model for risk factors of participant’s knowledge score about diabetic eye diseases (n = 1972).

	Simple linear regression		Multiple linear regression
	Beta coefficient (95% CI)	P	Beta coefficient (95% CI)	P
Age (years)	-0.03 (-0.04, 0.02)	<0.001	-0.02 (-0.03, -0.01)	<0.001
Males	0.32 (0.11, 0.54)	0.004	-0.001 (-0.19, 0.19)	0.991
Education
None	Reference		Reference
Elementary school	0.51 (0.23, 0.79)	<0.001	0.54 (0.30, 0.78)	<0.001
Junior high school	0.90 (0.59, 1.20)	<0.001	0.97 (0.69, 1.24)	<0.001
High school	1.08 (0.72, 1.43)	<0.001	0.96 (0.64, 1.29)	<0.001
College or above	1.18 (0.58, 1.79)	<0.001	1.28 (0.76, 1.79)	<0.001
Monthly family income (USD)
1–300	Reference		Reference
301–450	0.77 (0.35, 1.18)	<0.001	0.55 (0.21, 0.89)	0.001
451–750	0.87 (0.48, 1.25)	<0.001	0.46 (0.14, 0.78)	0.005
751–1500	0.44 (0.07, 0.81)	0.021	0.08 (-0.25, 0.40)	0.649
>1500	1.10 (0.68, 1.52)	<0.001	0.25 (-0.11, 0.61)	0.168
Yuecheng community (Nanyue community as reference)	0.19 (-0.03, 0.41)	0.090
Type 2 DM (type 1 as reference)	-0.55 (-1.18, 0.08)	0.087
Fasting blood glucose (mmol/L)	0.05 (-0.03, 0.12)	0.227
Using insulin (yes/no)	0.94 (0.57, 1.31)	<0.001	0.28 (-0.03, 0.58)	0.078
History of hypertension (yes/no)	0.25 (0.02, 0.47)	0.030	0.27 (0.09, 0.46)	0.003
Years since DM diagnosed	0.07 (0.04, 0.09)	<0.001	0.04 (0.02, 0.06)	<0.001
Diagnosed as DR (yes/no)	1.08 (0.57, 1.58)	<0.001	0.31 (-0.11, 0.73)	0.149
Used to have eye examinations (yes/no)	0.96 (0.69, 1.23)	<0.001	0.14 (-0.10, 0.38)	0.244
Told regular eye examinations should be done (never vs combined other options, never as reference)	2.75 (2.55, 2.95)	<0.001	2.07 (1.87, 2.28)	<0.001
Concern about vision loss (never vs combined other options, never as reference)	2.56 (2.32, 2.80)	<0.001	1.60 (1.37, 1.83)	<0.001

1 USD = 6.67 RMB, DM: diabetes mellitus, DR: diabetic retinopathy

^† All variables with P<0.05 in the simple regression analysis were included in the multiple regression analysis.