Impaired systolic blood dipping and nocturnal hypertension: an independent predictor of carotid intima-media thickness in type 1 diabetic patients

Objective: Type 1 diabetes in children predicts a broad range of later health problems including an increased risk of cardiovascular morbidity and mortality. This study aimed to evaluate whether nocturnal hypertension and impaired nocturnal dipping affect atherosclerosis in children and adolescents with type 1 diabetes and to investigate the relationship between atherogenic risk factors and carotid intima-media thickness (CIMT). Methods: One hundred fifty-nine type 1 diabetic patients and 100 healthy controls were included in the study. We investigated metabolic and anthropometric parameters such as body mass index (BMI), waist circumference, fasting glucose and insulin, serum lipids, 24 h ambulatory blood pressure monitoring (ABPM), and CIMT and compared these with those in control subjects (CS). Results: No difference was found between type 1 diabetic patients and CS in age, weight, waist/hip ratio, triglyceride, HDL-cholesterol level. However in children with type 1 diabetes, total cholesterol (p = 0.016), and LDL-cholesterol (p = 0.002) levels and CIMT (P < 0.001) were greater than those of controls. It was determined that 10% of type 1 diabetic patients had dyslipidemia. In 23.2% of type 1 diabetic patients, ABPM showed arterial hypertension. CIMT was significantly higher in the hypertensive group than in the nonhypertensive group (P = 0.003). Twenty-three (14.4%) diabetic patients had nocturnal hypertension. CIMT was significantly greater in the nocturnal hypertensive group (p = 0.023). Mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) dipping was significantly different in diabetic patients (P < 0.001). CIMT was correlated positively with Hba1c (r = 0.220, p = 0.037), and negatively with SBP dipping (r = -0.362, p = 0.020) in the diabetic patients. In stepwise regression analysis, Hba1c and SBP dipping emerged as a significant predictor of CIMT (beta = 0.300, p = 0.044, beta = 0.398 p = 0.009) contributing to 15.58% of its variability. Conclusion: These results provide additional evidence for the presence of subclinical cardiovascular disease (CVD) and its relation to hypertension in type 1 diabetic patients. They also indicate a significant relation between nocturnal hypertension, SBP dipping and increased arterial stiffness. It is also important to note that our findings reveal significant relationships between HBA1c cardiovascular changes and underline the importance of glucose control to predict CVD. (C) 2014 Elsevier Inc. All rights reserved.