OBJECTIVE- This cross-sectional study was aimed to investigate the iso
lated influence of obesity on peripheral sensorimotor and autonomic ne
uropathy in patients with long-term non-insulin-dependent diabetes mel
litus (NIDDM). RESEARCH DESIGN IND METHODS- Ninety-one long-term NIDDM
patients with a mean duration of 13.6 +/- 1.0 years and a mean age of
60.4 +/- 1.0 years were divided into two groups according to their bo
dy mass index (BMI) (lean with a BMI <26.5: n = 41, age = 58.6 +/- 1.7
years, BMI = 23.7 +/- 0.3 kg/m(2); and obese with a BMI greater than
or equal to 26.5: n = 50, age = 61.9 +/- 1.2 years, BMI = 30.5 +/- 0.5
kg/m(2)). The two groups were not different in age, duration, gender,
current parameters of glycemic control, number of smokers, cholestero
l, triglycerides, and systolic and diastolic blood pressure. Neuropath
ic late complications were scrutinized by a standardized clinical exam
ination that delivers a neuropathy score, pupillary autonomic neuropat
hy assessed by pupillometry, and cardiovascular autonomic neuropathy u
sing a standardized test battery.RESULTS - One-way analysis of varianc
e revealed that obese patients had poor results in the clinical neurop
athy test (overall score in obese vs. lean: 71.1 +/- 2.9 vs. 80.6 +/-
3.0 points, 2P = 0.0266; 100 points were absolutely normal). This was
particularly true for the discrimination perception (obese vs. lean: 6
7.0 +/- 4.0 vs. 81.7 +/- 3.3 points, 2P = 0.0073) and the reflex statu
s (obese vs. lean: 57.4 +/- 4.0 vs. 71.8 +/- 4.3 points, 2P = 0.0164).
Furthermore, obese patients had a poor result in the respiratory sinu
s arrhythmia (RSA) test, one of six autonomic function tests (RSA: obe
se vs. lean in average RSA percentile: 36.9 +/- 4.9 vs. 54.0 +/- 5.9%,
2P = 0.0264). CONCLUSIONS - Obesity influences sensorimotor and auton
omic neuropathic late complications. The poor result in RSA in obesity
may indicate an interrelation between pathogenesis of obesity and dis
orders of the respiratory and heart rhythm-generating control centers
in the brain stem. Moreover, it could be due to intrathoracic fat depo
sits that alter lung mobility. Body mass control may be an important a
pproach to reduce neuropathic complications. Beyond that, it seems nec
essary to control for body mass when comparing neuropathy in two group
s of patients with NIDDM.