Cigarette smoking and free radical activity in young adults with insulin-dependent diabetes.

Cigarette smoke is potentially capable of generating a high free radical load in the body and many patients with diabetes are smokers. This study was designed to investigate the relationship between long-term smoking and free radical activity in young adult insulin-dependent diabetic patients with no evidence of macrovascular disease. Eight-five patients (48 male) aged 17-40 years were studied. Mean duration of diabetes was 10.5 years (0.08-33) and 39 were cigarette smokers. All had normal serum creatinine levels. The free radical markers measured were: thiobarbituric acid reactive substances, glutathione peroxidase, and superoxide dismutase. No significant differences in thiobarbituric acid reactive substances, glutathione peroxidase, or superoxide dismutase, were found between the diabetic smokers and non-smokers. Also no difference was found comparing the diabetic patients with 40 non-diabetic control subjects (20 smokers). Persistent albuminuria was present in 16 patients (10 microalbuminuria) and free radical marker concentrations in these subjects were similar to the normoalbuminuric patients. This data suggests that any increase in free radical activity due to cigarette smoke is adequately scavenged in young adults with diabetes who are free of significant macrovascular disease.