A total of 1, 000 patients with non-insulin-dependent diabetes mellitus (467 males 533 females) were the subjects of this study designed to clarify the relationships between diabetic neurophathy and obesity. To determine the presence or absence of neuropathy, we interviewed all the subjects and asked them whether or not they had subjective symptoms such as insensitivity of the limbs and conditions associated with autonomic disorder. Furthermore, so long as situations permitted, a battery of tests were given them for the Achilles-tendon reflex and physiological nerve functions. To evaluate the extent of obesity, we used the body mass index (BMI) in accordance with the method proposed by the Japanese Society of Obesity
Results: In obese patients with BMI in excess of 24, subjective symptoms in the limbs, absence of ankle jerks and abnormality in the perception of vibration were observed with higher frequency than in those normal in weight with BMI from 20 to 24. Between these two groups, there was not much difference in the kind of therapy and blood sugara control they received, but the duration of the disease was shorter in the obese group. These findings made us believe that obesity serves as a promoter of neuropathy from the onset.
Even among the slenderly built subjects with BMI below 20, compared with the subjects normal in weight, a large number of them had subjective symptoms of peripheral neuropathy, absence of ankle jerks and abnormal levels of nerve conduction velocity. Between these two groups, there was not much difference in controlled blood sugar level and the duration of the disease, but the percentage of those treated with insulin was higher in the slender groupo than in the noramal-weight group. This fact suggested that severe diabetes might have contributed to the onset of neuropathy.
From the above, we concluded that there is a close link between diabetic neuropathy and obesity, and that proper weight control is a key to the prevention of this type of neuropathy.