Distal sensorimotor polyneuropathy (DSPN) is frequently observed in diabetes, and metabolic conditions such as obesity and metabolic syndrome (MetS) may influence early nerve alterations. A study published in Diabetes Metabolism Research and Reviews investigated whether obesity and MetS were associated with measures of neuropathy over five years in individuals with recent-onset type 2 diabetes mellitus (T2DM) and those with normal glucose tolerance (NGT).
The study enrolled 355 individuals with recently diagnosed T2DM and 181 individuals with NGT who were matched for age and sex. All participants underwent standardized reference testing to assess DSPN. Intraepidermal nerve fibre density (IENFD) was measured in a subgroup of participants that included 100 individuals with T2DM and 117 with NGT. Follow-up evaluations after five years were available for subgroups consisting of 198 participants with T2DM and 64 with NGT. MetS was defined according to International Diabetes Federation criteria, and DSPN was determined using the Toronto consensus definition.
After adjusting for age, sex, height, smoking history, and glycated haemoglobin (HbA1c), lower IENFD values were observed with increasing body weight and with a greater number of MetS components among individuals with NGT. This association was not present in the T2DM group. Higher body weight was also linked with reduced sural sensory nerve action potential in both groups. Among individuals with NGT, higher baseline weight was associated with the development of DSPN during follow-up.
Among participants with recent-onset T2DM, baseline obesity and the presence of MetS were associated with increased odds of neuropathic deficits at the five-year assessment. The estimated odds ratio (OR) for neuropathic deficits was 3.00 (95% confidence interval [CI] 1.06-8.51) for obesity and 8.25 (95% CI 1.02-66.91) for MetS. These findings indicate that higher body weight was independently associated with early nerve fibre loss and dysfunction. In individuals with recent-onset T2DM, obesity and MetS present at baseline were associated with neuropathic deficits detected five years later.
