Masked hypertension and correlation between body composition and nighttime blood pressure parameters in children and adolescents with obesity

INTRODUCTION: Masked hypertension is defined as having a normal blood pressure (BP) in the office but elevated BP outside the office. This study aimed to determine the prevalence of masked hypertension in participants with obesity and to examine the correlation between body composition, dietary intake and ambulatory blood pressure parameters. MATERIALS AND METHODS: The cross-sectional study of participants with obesity was conducted in the pediatric nutrition clinic of a University Hospital in Thailand. Demographic and anthropometric data, dietary intake, body composition analysis and ambulatory blood pressure monitoring were assessed in all participants. All parameters were compared between the group with masked hypertension and the normotensive group. Correlations between the parameters were analyzed. RESULTS: Among 49 children with obesity, 23 (47%, 95% confidence interval 34.7, 59.2%) had masked hypertension. Compared with the normotensive group, the group with masked hypertension had a greater mean BMI z-score (4.7 vs. 3.0, P = 0.003), a greater mean of body fat percentage (45 vs. 40, P = 0.012) and a greater total energy intake percentage of dietary reference intake (115 vs. 93, P = 0.034). Multivariate analysis showed that BMI z-score was significantly associated with masked hypertension. Interestingly, mean nighttime SBP positively correlated with BMI z-score and body fat percentage. Moreover, there were negative correlations between fruit intake portion per week and nighttime and 24-h SBP index. However, multivariate linear regression did not show significant correlation between these parameters. CONCLUSIONS: Masked hypertension was frequent in participants with obesity. The greater BMI z-score and percentage of body fat mass correlated with higher nighttime SBP.