Cigarette smoking and plasma total homocysteine levels in young adults with type 1 diabetes

OBJECTIVE - The purposes of this study were to compare plasma total homocys teine (tHcy) levels, a recognized cardiovascular risk factor, in nondiabeti c subjects and type I diabetic patients, and to evaluate whether chronic ci garette smoking had a deleterious effect on plasma tHcy levels in type 1 di abetic patients. RESEARCH DESIGN AND METHODS - Plasma tHcy concentrations were measured in 6 0 young type 1 diabetic patients without clinical evidence of macroangiopat hy and in 30 healthy control subjects who were matched for age, sex, BMI, a nd smoking habit. RESULTS - Plasma tHcy levels were significantly higher in type I diabetic p atients than in control subjects (12.5 +/- 4.8 vs. 10.3 +/- 2.2 mu mol/l, P = 0.01). After stratification by smoking status, diabetic smokers had valu es for age, sex, BMI, lipids, creatinine, blood pressure, glycometabolic co ntrol, diabetes duration, and microvascular complications that were superim posable on their nonsmoking counterparts. Nevertheless, plasma tHcy levels were markedly elevated in diabetic smokers Versus nonsmokers (15.5 +/- 5.7 vs. 10.6 +/- 3 mu mol/l, P < 0.0001) in a dose-dependent fashion (P < 0.000 1, by analysis of variance when subjects were categorized for the number of cigarettes smoked daily). CONCLUSIONS - Chronic cigarette smoking seems to adversely affect plasma tH cy levels in young adults with type I diabetes.