INS and diabetes mellitus: After adjusting for all plausible predictors (BMI, educational level, physical activity, presence of chronic comorbidities, early onset of DM, duration of DM, HbA1C%, Insulin as initiation therapy, current insulin therapy, and presence of any diabetic complications), a higher risk of DPN was reported among past and current smokers ([OR = 4.10; 95% CI = 1.84-9.17] and [OR = 2.48; 95% CI = 1.06-5.83], respectively).