Height may increase the risk of diabetic polyneuropathy, but previous studies are inconclusive. Our purposes were to further examine the hypothesis that height (HT) is an independent risk factor for diabetic polyneuropathy and to determine which electrophysiologic measures are influenced by HT in diabetic subjects. We studied 170 Japanese American men (ages 43-73 years, mean 61) including: 69 diabetic men (mean HT 166 cm), 54 normal men (mean HT 167 cm), and 47 men with impaired glucose tolerance (IGT) (mean HT 164 cm), measuring 28 nerve conduction study (NCS) parameters. We used data from normal men in developing regression models to adjust NCS parameters for HT, age, and temperature. Factor analysis was employed to reduce the 28 NCS parameters to five physiologically meaningful factors, one of which, a factor representing median and peroneal sensory amplitudes, was significantly correlated with HT (r = -0.38, P = 0.0011) in diabetic men; taller subjects having smaller sensory nerve amplitudes. No significant correlation was found between this factor and body mass index. This factor had no correlation with HT in normal or IGT men. Our data do not confirm previous reports of associations between HT and slowed motor conduction velocities in diabetic subjects. This study does, however, support the hypothesis that HT is an independent risk factor for sensory polyneuropathy in diabetic subjects.