Background: Altered circadian and ultradian blood pressure (BP) and heart rate (HR) rhythmicity has been described in many diseases with increased cardiovascular risk.
Objective and hypotheses: We tested the hypothesis that rhythmicity in obese children is changed, compared to healthy subjects.
Method: Circadian and ultradian BP and HR rhythmicity was assessed with Fourier analysis from 24-h ambulatory BP measurement (ABPM) in 75 obese children, 45% girls, BMI SDS median 2.79 (interquartile range (IQR) 2.54 to 3.41), median age 11.6 years (IQR 9.0 to 13.6) and compared with an age- and gender matched healthy control group of 150 subjects (45% girls) with BMI SDS median 0.32 (IQR −0.39 to −1.13), median age 11 years (IQR 8.0 to 13.0). Multivariate regression analysis was applied to identify significant independent factors explaining rhythmicity variability in this population. Subgroup analysis of non-hypertensive participants was performed.
Results: Prevalence of 24- and 6-h BP as well as 12-h HR rhythmicity in obese group was lower (P=0.03, P=0.02, and P<0.0001). Prevalence of 8-h HR rhythmicity was higher in obese children (P<0.0001). Prevalence of BP rhythmicity excluding hypertensive participants showed comparable results with lower prevalence for 24- and 6-h BP rhythmicity in obese participants (P=0.02 and P=0.03). 24-h BP and HR acrophase was delayed in obese children (P=0.004 and P<0.0001), 24-h BP amplitude was comparable (P=0.07), 24-h HR amplitude was flattened (P≤0.0001). BP Mesor in obese cohort was higher (P=0.02) and HR Mesor was comparable (P=0.1). Multivariate regression analysis failed to identify anthropometric or blood pressure parameters explaining the variability of BP and HR rhythmicity.
Conclusion: We showed altered prevalence and parameters of circadian and ultradian BP and HR rhythmicity in obese children compared to healthy controls. This was independent of anthropometric and blood pressure values, suggesting other factors being involved in altered cardiovascular rhythmicity.
01 Oct 2015 - 03 Oct 2015