Body mass is a poor predictor of peak plantar pressure in diabetic men.

OBJECTIVE: To examine the relationship between peak plantar pressure during walking and body mass in diabetic patients and age-matched control subjects. RESEARCH DESIGN AND METHODS: A volunteer sample of 56 male diabetic veterans (12 insulin dependent, 44 non-insulin dependent) with a mean age of 58.9 yr, mean duration of diabetes of 16.9 yr, and mean vibration perception threshold of 30.8 and 27 age-matched nondiabetic control subjects comprised the study.
RESULTS: Peak plantar pressure was measured with a 1000-element piezoelectric platform during the first step of gait. The correlation between body mass and peak pressure was found to be only 0.37 in the patients with diabetes and 0.36 in the control subjects, indicating that body mass accounts for less than 14% of the variance in peak plantar pressure. The body mass and peak plantar pressure of the 14 patients who experienced plantar ulcers was not significantly different from those who did not ulcerate, but vibration perception thresholds and monofilament perception thresholds of the ulcer patients were significantly higher.
CONCLUSIONS: Although the correlation between body mass and peak plantar pressure is statistically significant, the functional relationship between the two variables is weak. Elevated plantar pressures are as likely to occur in small individuals as they are in those with large body mass. Foot deformity, in the presence of neuropathy and other permissive factors, is itself likely to be an important risk factor for plantar ulceration in diabetes, and this hypothesis deserves further exploration.