National School-Based Health Lifestyles Intervention in Chinese Children and Adolescents on Obesity and Hypertension

Abstract

Introduction: This study aimed to examine the effectiveness of the national school-based intervention on both obesity and high blood pressure in Chinese children and adolescents aged 6-18 years. Methods: The national school-based cluster non-randomized controlled trial was done in seven provinces from September 2013 to February 2014. A total of 23,175 children and adolescents in the control group and 25,702 in the intervention group were included in this trial with a mean follow-up of 6.7 ± 0.9 months. Mixed-effects regression models were used to evaluate the effect of the interventions on body weight and blood pressure (BP). Results: A significant upward in the body mass index (BMI) levels but downward in systolic BP (SBP), diastolic BP (DBP), BMI Z-scores, SBP Z-scores, and DBP Z-scores were witnessed in the intervention group compared to those in the control group (<0.001). Subgroup analyses presented significant intervention effects in children aged 6-12 years for BMI, SBP, DBP, and their standardized values Z-scores, but no effective results were found in adolescents aged 13-18 years. Stratification analyses based on the dynamic weight changes presented non-differential HBP, SHBP, and DHBP prevalence gaps between the control and intervention groups. Children aged 6-12 years with higher BMI percentiles at baseline presented obvious declines in SBP and DBP standardized values Z-scores. Conclusion: A mean 6-month multi-centered school-based comprehensive obesity intervention in China yields a small to null effect on obesity and hypertension with increasing age; the early age before 12 years may be the key period for interventions, and the younger, the better. Precise and high-intensity interventions targeting the population at different stages of childhood and adolescence are urgently needed to be developed. Clinical Trial Registration: https://www.clinicaltrials.gov/, identifier: NCT02343588.

Keywords: blood pressure; children and adolescents; intervention; non-randomized controlled trials; obesity.

Figure 1

Trial profile and the flow of the participants in the trial.

Figure 2

The Health Lifestyles Intervention in Chinese Children and Adolescents (HLI-CCA) intervention model with four strategy designs.

Figure 3

Analysis by age group of the intervention effects on child body mass index (BMI), systolic blood pressure (SBP), and diastolic blood pressure (DBP). β values indicate the effects of interventions for BMI, systolic BP, and diastolic BP using the mixed-effects regression models in each age group adjusting for age, sex (total), and the baseline disequilibrium for socio-demographic indicators. The subfigure (A) reflect the intervention effect in BMI, (B) for BMI Z-Score, (C) for systolic blood pressure, (D) for systolic blood pressure Z-Score, (E) for diastolic blood pressure, and (F) for diastolic blood pressure Z-Score.

Figure 4

Analysis by age group of the intervention effects on overweight and obesity (OWOB), systolic high blood pressure (SHBP), diastolic high blood pressure (DHBP), and high blood pressure (HBP). Odds ratios (ORs) indicate the effect of interventions for BMI, systolic BP, and diastolic BP using the mixed-effects regression models in each age group adjusting for age, sex (total), and the baseline disequilibrium for socio-demographic indicators. The subfigure (A) reflect the intervention effect in overweight and obesity, (B) for high blood pressure, (C) for systolic high blood pressure, (D) for diastolic high blood pressure.

Figure 5

Effect of interventions on high blood pressure (HBP, A for 6-12 years, B for 13-18 years), systolic high blood pressure (SHBP, C for 6-12 years, D for 13-18 years), and diastolic high blood pressure (DHBP, E for 6-12 years, F for 13-18 years) in different BMI Z-score change groups. Three BMI Z-score change groups were defined for the BMI Z-score changes between baseline and post-intervention: BMI Z-score changes between −0.5 and 0.5 as the Stable group, < −0.5 as the Decline group, and more than 0.5 as the Increase group. Red circles represent the prevalence of HBP, SHBP, and DHBP in the control group at baseline and blue circles represent that after the intervention. The prevalence of HBP, SHBP, and DHBP in the intervention group at baseline is represented by red triangles and that after the intervention is represented by blue triangles. Green bars represent the prevalence gaps of HBP, SHBP, and DHBP between the baseline and post-intervention.