Profound vasoconstrictive effect of cigarette smoking in diabetics with autonomic neuropathy.
Changes in leg skin temperature during and after cigarette smoking were examined in 25 diabetics with autonomic neuropathy (au-neuropathy) (mean age 52 +/- 2 years) and 23 without (mean age 49 +/- 2 years), and 15 normal controls (mean age 49 +/- 2 years) using a Thermoviewer JTG 3300. All subjects were habitual smokers. Japanese Seven Star cigarettes (each containing 1.2 mg nicotine) were used for the test. Tender brand cigarettes (0.3 mg) were used additionally to compare the effect of nicotine content on the results. The smoking-stimulated thermographic pattern in the control group was rather flat, with a slight decrease in temperature followed by a slight increase before returning to the baseline level 15-20 min after smoking. The frequency of the typical temperature decreasing pattern, characterized by a profound decrease and gradual return to the baseline level in about 1 h, was significantly higher in the diabetic group than in the control group (33/48 vs 1/15; P less than 0.005). A comparison of the two diabetic subgroups revealed that the frequency was considerably higher in the subgroup with au-neuropathy (23/25 vs 10/23). These results suggest that au-neuropathy affects smoking-induced vasoconstriction in diabetic subjects. The maximum temperature decreases recorded were 1.5 +/- 2.0 and 2.69 +/- 0.24 degrees C in the controls and diabetics with au-neuropathy, respectively. The effect of Tender cigarettes with a low nicotine content was much weaker than that of Seven Star, which further suggests that smoking-induced vasoconstriction was also nicotine-dependent.