Table 5.

Analysis of DSPN risk factors for confounding bias controlled by multiple models.

Variable	Model 1		Model 2		Model 3		Model 4
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
25(OH)D, ng/mL	0.73 (0.69–0.77)	<0.001	0.72 (0.67–0.76)	<0.001	0.71 (0.67–0.76)	<0.001	0.69 (0.65–0.74)	<0.001

Model 1 was unadjusted. Model 2 was adjusted for age, BMI, and gender. Model 3 was adjusted for age, BMI, gender, smoke, and exercise. Model 4 was adjusted for age, BMI, gender, smoke, exercise, SBP, DBP, DM duration, TG, TC, HbA1c, and IR. 25(OH)D, 25-hydroxyvitamin D; DSPN, distal symmetric polyneuropathy; OR, odds ratio; CI, confidence interval; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; DM, diabetes mellitus; TG, triglycerides; TC, total cholesterol; HbA1c, glycated hemoglobin; IR, insulin resistance.