Type 2 diabetes in children is a recent phenomenon, and current evidence about diabetes and hypertension is based on adult studies. Adults with diabetes have changes in 24-h ambulatory blood pressure (BP) profiles, including a decrease in sleep dip (the decline in BP that normally occurs during sleep) and increased systolic blood pressure (SBP), that are associated with early cardiovascular disease (1).
This cross-sectional study compared 24-h BP and heart rate (HR) profiles of Hispanic and African-American adolescents recently diagnosed with type 2 diabetes with the profiles of two groups of 10 healthy control subjects matched for age, sex, height, and race/ethnicity (2). BP and HR were monitored every 30 min for 24 h using an ambulatory monitor (model 90207; SpaceLabs, Redmond, Washington). Simultaneous recording of activity was monitored by the Motionlogger actigraph (Ambulatory Monitoring, Ardsley, New York). A mixed-model approach was used to examine differences in individual BP and HR measurements in the study and comparison groups.
The study group consisted of 10 adolescents with type 2 diabetes (6 males and 4 females). Mean age at diagnosis was 13.58 years, mean length of diagnosis was 10 months, and mean blood glucose on the day of monitoring was 149.30 mg/dl (SD 81.99). Mean weight was 82.53 kg (range 62.7–129.3) in the study group and averaged 60.89 kg (43–85) in the comparison groups. Compared with adolescents without diabetes, adolescents with type 2 diabetes had significantly smaller mean sleeping SBP dip even after controlling for weight (P = 0.008).
The model for SBP indicated a significant difference by group, [F (2, 799) = 4.84, P = 0.0082], position [F (2, 799) = 28.28, P < 0.0001], and group by position interaction [F (4, 799) = 4.92, P = 0.0006]. Reclining and sitting positions were associated with lower SBP compared with a standing position in the comparison groups, whereas only reclining was associated with lower SBP in the group with diabetes. The least-squares mean SBP decreased an average 12.5 points while reclining in the comparison groups, but it was only 3.8 points lower in the subjects. The model for HR indicated a significant difference in group-by-activity interaction, [F (2, 801) = 3.55, P = 0.0291], group effect [F (2, 801) = 24.13, P < 0.0001], position [F (2, 801) = 77.62, P < 0.0001], and activity [F (1, 801) = 4.12, P = 0.0428]. HR was significantly lower in the reclining and sitting positions for all subjects, but the group with diabetes had higher HR on average than either comparison group. Activity was unrelated to HR in the group with type 2 diabetes, while it was positively related in the two comparison groups.
This study provided evidence that changes in BP and HR are evident early in the course of type 2 diabetes in adolescents and may predict increased cardiovascular morbidity during young adulthood.
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Address correspondence to Christine A. Brosnan, University of Texas Health Science Center School of Nursing, Systems and Technology, 1100 Holcombe Blvd., Suite 5.518, Houston, TX 77030. E-mail: [email protected].
