The metabolic syndrome in patients with type 1 diabetes mellitus. Associations with cardiovascular risk factors and cardiovascular morbidity

Background and Purpose: Type 1 diabetes is known to be associated with increased cardiovascular disease in the presence of nephropathy and hypertension. It was the aim of the present study to elucidate whether or not clinical findings of metabolic syndrome (MS) are further increasing cardiovascular morbidity among type 1 diabetics. Methods: In the present cross-sectional study, 1,241 type 1 diabetics were included. These patients attended the Diabetes Clinic Karlsburg, Germany, from February 1, 2002 to December 31, 2003. The presence of the following findings was taken into consideration as clinical features of MS in type 1 diabetes: fasting triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), body mass index (BMI), daily insulin requirement/kg body weight (b.w.), increased blood pressure > 130/85 mmHg, including overt arterial hypertension. In each of the five categories the highest quintile in each sample was assessed: TG 2.9 ± 3.6 mmol/l, HDL-C 1.48 ± 0.46 mmol/l, BMI 29.1 ± 4.98 kg/m2 height, insulin requirement 0.71 ± 0.23 IU/kg b.w., systolic blood pressure 130 ± 12.3 mmHg. MS was defined as the presence of at least three categories. Among 1,241 type 1 diabetics (651 men, 590 women), 226 patients (129 men, 97 women) fulfilled the criteria of MS. The risk of MS was assessed by multiple regression analysis. Risk variables were: age, diabetes duration, sex, glycated hemoglobin (HbA1C), actual smoking, neuropathy, albumin excretion rate (AER), regular alcohol consumption, retinopathy, peripheral vascular disease (PVD), coronary heart disease (CHD), TGs, HDL-C, low-density lipoprotein cholesterol (LDL-C), cholesterol, blood pressure increase, BMI, increased insulin requirement, and foot syndrome. After adjusting for age, the variables were separately included into the mathematical model. The risk of MS was assessed after excluding the variables defining MS. Results: Type 1 diabetics with MS were characterized by higher age (46 vs. 36 years; p < 0.01), and longer diabetes duration (19 vs. 16 years; p < 0.01). The risk of MS was independently associated (odds ratios) with higher age (40-59 years; 4.21; p < 0.01), increased HbA1C (1.41; p < 0.01), PVD (2.28; p < 0.01), CHD (2.19; p < 0.01), and the foot syndrome (4.17; p < 0.01). There were no significant associations of MS with type 2 diabetes heredity (first and second degree). Conclusion: Patients with type 1 diabetes and the presence of findings of MS are suffering from increased cardiovascular morbidity. The risk of MS increases with the age and HbAK. Life style factors such as weight gain and muscular inactivity seem to have an influence on the pathogenesis of MS in type 1 diabetes, thereby increasing cardiovascular morbidity.