To study incident diabetic polyneuropathy (DPN) prospectively during the first 13 years after a screening-based diagnosis of type 2 diabetes and determine the associated risk factors for the development of DPN.
We assessed DPN longitudinally in the Danish arm of the Anglo-Danish-Dutch study of Intensive Treatment of Diabetes in Primary Care (ADDITION) using the Michigan Neuropathy Screening Instrument questionnaire (MNSIQ), defining DPN with scores ≥4. Risk factors present at the diabetes diagnosis associated with the risk of incident DPN were estimated using Cox proportional hazard models adjusted for trial randomization group, sex, and age.
Of the total cohort of 1,533 people, 1,445 completed the MNSIQ at baseline and 189 (13.1%) had DPN at baseline. The remaining 1,256 without DPN entered this study (median age 60.8 years [interquartile range 55.6; 65.6], 59% of whom were men). The cumulative incidence of DPN was 10% during 13 years of diabetes. Age (hazard ratio [HR] 1.03 [95% CI 1.00; 1.07]) (unit = 1 year), weight (HR 1.09 [95% CI 1.03; 1.16]) (unit = 5 kg), waist circumference (HR 1.14 [95% CI 1.05; 1.24]) (unit = 5 cm), BMI (HR 1.14 [95% CI 1.06; 1.23]) (unit = 2 kg/m2), log2 methylglyoxal (HR 1.45 [95% CI 1.12; 1.89]) (unit = doubling), HDL cholesterol (HR 0.82 [95% CI 0.69; 0.99]) (unit = 0.25 mmol/L), and LDL cholesterol (HR 0.92 [95% CI 0.86; 0.98]) (unit = 0.25 mmol/L) at baseline were significantly associated with the risk of incident DPN.
This study provides further epidemiological evidence for obesity as a risk factor for DPN. Moreover, low HDL cholesterol levels and higher levels of methylglyoxal, a marker of dicarbonyl stress, are identified as risk factors for the development of DPN.