Implications of nocturnal hypertension in children and adolescents with type 1 diabetes.

OBJECTIVE: Diabetes is associated with atherogenic risk factors. Hypertension has a major influence on cardiovascular disease in diabetic patients. Ambulatory blood pressure monitoring (ABPM) is useful for identifying nocturnal hypertension. Carotid intima-media thickness (cIMT) is a good measure for identifying subclinical atherosclerosis. This study aimed to evaluate whether nocturnal hypertension affects atherosclerosis in children and adolescents with type 1 diabetes and to investigate the relationship between atherogenic risk factors and cIMT.

RESEARCH DESIGN AND METHODS: ABPM and cIMT were measured in 82 diabetic children and adolescents. We reviewed the hemoglobin A(1c) levels, 24-h urine microalbumin excretion, lipid profiles, and duration of diabetes. Nocturnal hypertension was defined as hypertension observed only at night.

RESULTS: Forty-three (52%) subjects were hypertensive, and 30 subjects were classified as having nocturnal hypertension. cIMT was higher in the nocturnal hypertensive group than in the normotensive group (0.44 ± 0.03 vs. 0.42 ± 0.04 mm, P = 0.026). Among children and adolescents with nonhypertensive blood pressure levels in clinic blood pressure monitoring, cIMT and daytime blood pressure were higher in the nocturnal hypertensive group. All ABPM parameters were significantly related to cIMT in multiple linear regression analysis.

CONCLUSIONS: This study showed significantly increased cIMT and daytime blood pressure in diabetic children and adolescents with nocturnal hypertension. ABPM may be a useful method for detecting the macrovascular complications of type 1 diabetes. Longitudinal studies are needed to find the causes of nocturnal hypertension and to evaluate the effect of nocturnal hypertension on atherosclerosis in type 1 diabetes.