Smoking is a Major Contributor of Peripheral Nerve Damage in Diabetic Polyneuropathy

Background & Purpose: So far it remains unclear whether smoking-induced microangiopathic changes contribute to the damage of peripheral nerves in diabetic polyneuropathy (DPN). The aim of this study was to investigate the correlation between cigarette smoking and peripheral nerve damage in diabetic polyneuropathy. Methods: We performed 3 T MR-neurography of the right leg in 77 patients (34 never smokers, 32 ex-smokers, 11 active smokers; female: 32, male: 35). Semi-automated analysis of lesion load and nerve average diameter was performed. In addition, clinical, serological and electrophysiologic parameters were assessed. Results: A significantly higher load of T2w-hyperintense sciatic nerve lesions were found in smokers compared to ex-smokers (20.8% [+ or -] 7.2 vs. 9.% [+ or -] 1.1 respectively 7.4% [+ or -] 0.9, respectively p < 0.001). Also, we identified a significantly larger diameter of sciatic nerve in smokers (162 [mm.sup.2] [+ or -] 18) in comparison to ex-smokers (130.2 [mm.sup.2] [+ or -] 5) and to never smokers (127 [mm.sup.2] [+ or -] 5; p = 0.024). Lesion load and diameter of sciatic nerve also showed a negative correlation between peroneal nerve conduction velocity (r = -0.29; p = 0.008 respectively r = -0.28; p = 0.012) and Neuropathy Disability Score (r = 0.32; und r = 0.33; respectively p < 0.001). We did not find a correlation for HbA1c-values. Conclusion: Our results reveal a significant association of smoking on peripheral nerve damage in diabetic neuropathy. Both peripheral nerve diameter and increased lesion load of sciatic nerve are further associated with a lower nerval conduction velocity.