Body mass index trajectory from childhood to puberty and high blood pressure: the China Health and Nutrition Survey.

Objectives: The prevalence of childhood hypertension is rising in parallel with the increasing prevalence of overweight and obesity in children. How growth trajectories from childhood to puberty relate to high blood pressure (HBP) is not well defined. We aimed to characterise potential body mass index (BMI) dynamic changing trajectories from childhood to puberty and investigate their association with HBP.

Design: A dynamic prospective cohort.

Setting: China Health and Nutrition Survey 1991-2015.

Participants: There were 1907 participants (1027 men and 880 women) in this study.

Outcomes: The primary outcome was HBP defined as systolic blood pressure (SBP)/diastolic blood pressure (DBP) exceeding the standards or diagnosis by medical records or taking antihypertensive medication.

Results: A model of cubic parameters with three groups was chosen, labelled as normal increasing group (85.16%, n=1624), high increasing group (9.81%, n=187) and resolving group (5.03%, n=96). Compared with the normal increasing group, the unadjusted HRs (95% CIs) for the resolving and high increasing groups were 0.91 (0.45 to 1.86) and 1.88 (1.26 to 2.81), respectively. After adjusting for baseline age, region, sex, baseline BMI z-score, baseline SBP and baseline DBP in model 3, the HRs (95% CIs) for the resolving and high increasing groups were 0.66 (0.30 to 1.45) and 1.56 (1.02 to 2.38).

Conclusions: These results indicate that the BMI trajectories from childhood to puberty have significant impact on HBP risk. Puberty is a crucial period for the development of HBP.