# Obesity and Metabolic Syndrome Predict Polyneuropathy Over 5 Years in Recent‐Onset Type 2 Diabetes and Normal Glucose Tolerance

## TL;DR

Higher weight and metabolic syndrome are linked to nerve damage in people with new type 2 diabetes or normal glucose levels, even without high blood sugar.

## Contribution

The study shows obesity and metabolic syndrome predict nerve damage over 5 years in recent-onset type 2 diabetes and normal glucose tolerance.

## Key findings

- Higher baseline weight is associated with incident distal sensorimotor polyneuropathy in normal glucose tolerance.
- Obesity and metabolic syndrome at baseline predict neuropathic deficits in type 2 diabetes after 5 years.
- Weight is independently linked to early nerve fiber loss and dysfunction, regardless of hyperglycemia.

## Abstract

To evaluate the impact of obesity and metabolic syndrome (MetS) on distal sensorimotor polyneuropathy (DSPN) over 5 years of recent‐onset type 2 diabetes and normal glucose tolerance (NGT).

Individuals with recent‐onset type 2 diabetes and NGT (n = 355/181) matched for age and sex underwent reference tests of DSPN. Intraepidermal nerve fibre density (IENFD) was assessed in a subset (n = 100/117). Subgroups (n = 198/64) were reevaluated 5 years later. MetS was defined by International Diabetes Federation criteria and DSPN by the Toronto consensus criteria.

After adjustment for age, sex, height, smoking history, and HbA1c, IENFD was inversely associated with weight and the number of MetS components in NGT, but not in type 2 diabetes. Lower sural sensory nerve action potential was associated with higher weight in both groups. Higher baseline weight was associated with incident DSPN in NGT. Obesity and MetS at baseline were associated with higher odds of neuropathic deficits at follow‐up in type 2 diabetes (OR [95% CI] for obesity 3.00 [1.06–8.51] and MetS 8.25 [1.02–66.91]).

Higher weight is independently associated with early nerve fibre loss and dysfunction, regardless of hyperglycaemia. In recent‐onset type 2 diabetes, obesity and MetS predict neuropathic deficits 5 years later, suggesting that timely weight management may be critical to prevent DSPN.