The Association of Pediatric Obesity With Nocturnal Non-Dipping on 24-Hour Ambulatory Blood Pressure Monitoring

Abstract

Background: Obesity has been linked with abnormal nocturnal dipping of blood pressure (BP) in adults, which in turn is associated with poor cardiovascular outcomes. There are few data regarding abnormal dipping status in the obese pediatric population. The goal of this study was to further describe the relationship between obesity and non-dipping status on ambulatory blood pressure monitor (ABPM) in children.

Methods: We conducted a cross-sectional study using a database of patients aged 5-21 years who had undergone 24-hour ABPM at Seattle Children's Hospital from January 2008 through May 2014. Subjects were grouped by body mass index (BMI) into lean (BMI 15th-85th percentile) and obese (BMI >95th percentile) groups.

Results: Compared to lean subjects (n = 161), obese subjects (n = 247) had a prevalence ratio (PR) for non-dipping of 2.15, adjusted for race (95% confidence interval (CI) = 1.25-3.42). Increasing severity of obesity was not further associated with nocturnal non-dipping. Nocturnal non-dipping was not associated with left ventricular hypertrophy (PR = 1.01, 95% CI = 0.71-1.44).

Conclusions: These results suggest that in children, just as in adults, obesity is related to a relatively decreased dipping in nocturnal BP.

Keywords: ABPM; ambulatory blood pressure monitor; blood pressure; hypertension; nocturnal dipping; obesity; pediatrics..

Figure 1.

A total of 1,620 ABPMs were performed between January 2008 and May 2014, of which 1,372 were first-time ABPMs. Ninety eight of these were of inadequate quality to be interpretable. Following application of exclusion criteria, 408 first-time ABPMs were eligible for analysis including 161 in lean subjects and 247 in obese subjects. Ninety overweight subjects were not included. Abbreviations: ABPM, ambulatory blood pressure monitor.

Figure 2.

Mean nocturnal dipping was decreased in the obese group compared to the lean group. ( A ) Mean systolic dip was 15.1% ± 4.6% in lean subjects compared to 12.4 ± 5.6% in obese subjects ( P -value < 0.001). (B) Mean diastolic dip was 22.2 ± 6.0% in lean subjects compared to 18.5 ± 7.0% in obese subjects ( P -value < 0.001).